Modbus Protocol Guide EM-RS485 154-0023-0A

Modbus Protocol Guide EM-RS485 154-0023-0A
Modbus Protocol Guide
EM-RS485
Senva Sensors
9290 SW Nimbus Ave
Beaverton, OR 97008
154-0023-0A
Rev.
0A
Release Date
11/22/2016
By
DLE
Description of Change
Initial Release
Copyright ©2016. All rights reserved. This document contains Senva Sensors proprietary
information, and may not be reproduced or distributed without written permission.
ECR
---
Table of Contents
Readable .................................................................................................................................. R
Access
Writable .................................................................................................................................... W
Legend
Writable with 0 only (statistics reset, see System Readings) ............................... W0
Saved in non-volatile configuration memory ........................................................... NV
Configuration ................................................................................................................................................ 6
Holding Registers ......................................................................................................................................... 8
System Configuration .......................................................................................................................................................................8
R102
Reset Reason ......................................................................................UINT16 ................... R .............................8
R103
Reset Count ........................................................................................UINT16 ................... R/NV ......................8
R104/05
Up Time ................................................................................................UINT32 ................... R .............................8
R111
Identify Meter ....................................................................................BOOL ....................... R/W ........................8
R112
Auto Protocol .....................................................................................BOOL ....................... R/W/NV ................ 9
R114
Auto Baud Rate .................................................................................BOOL ....................... R/W/NV ................ 9
R116
Auto Parity ..........................................................................................BOOL ....................... R/W/NV ................ 9
R117
Auto Data Bits ....................................................................................BOOL ....................... R/W/NV ................ 9
R118
Auto Stop Bits ....................................................................................BOOL ....................... R/W/NV ............. 10
R122
RS485 Protocol ..................................................................................UINT16 ................... R/W/NV ............. 10
R123
Slave Address .....................................................................................UINT16 ................... R/W/NV ............. 10
R124/25
RS485 Baud Rate ...............................................................................UINT32 ................... R/W/NV ............. 10
R126
RS485 Parity ........................................................................................UINT16 ................... R/W/NV ............. 11
R127
RS485 Data Bits .................................................................................UINT16 ................... R/W/NV ............. 11
R128
RS485 Stop Bits ..................................................................................UINT16 ................... R/W/NV ............. 11
R133
Temperature Units ...........................................................................UINT16 ................... R/W/NV ............. 11
R134
Smoothed Temperature Response Time ................................UINT16 ................... R/W/NV ............. 12
R142
Smoothed Frequency Response Time .....................................UINT16 ................... R/W/NV ............. 12
R144
Smoothed Voltage Response Time ...........................................UINT16 ................... R/W/NV ............. 12
R152
System Current Sensor Technology ..........................................UINT16 ................... R .......................... 12
R153
Angle Units .........................................................................................UINT16 ................... R/W/NV ............. 13
R154
Smoothed Current Response Time ...........................................UINT16 ................... R/W/NV ............. 13
R161
System Phase Selection .................................................................UINT16 ................... R/W/NV ............. 13
R162
Power Spectrum ...............................................................................UINT16 ................... R/W/NV ............. 13
R163
Power Units ........................................................................................UINT16 ................... R/W/NV ............. 14
R164
Smoothed Power Response Time ..............................................UINT16 ................... R/W/NV ............. 14
R170
Energy Data Type .............................................................................BOOL ....................... R/W/NV ............. 14
R173
Energy Units .......................................................................................UINT16 ................... R/W/NV ............. 15
R174/75
Energy Timestamp ...........................................................................FLOAT ..................... R .......................... 15
R181
Demand Window Synchronization ...........................................UINT16 ................... R/W/NV ............. 15
R183
Demand Window Time ..................................................................UINT16 ................... R/W/NV ............. 16
R184/85
Elapsed Demand Window ............................................................UINT32 ................... R/W0 .................. 16
R186/87
Demand Window Count ................................................................UINT32 ................... R/NV ................... 16
R190/91
Reset Meter Configuration ...........................................................UINT32 ................... W ......................... 17
R192/93
Reset Meter Statistics ......................................................................UINT32 ................... W ......................... 17
R194
Energy Reset Count .........................................................................UINT16 ................... R/NV ................... 17
R195
Auto Reset Statistics ........................................................................BOOL ....................... R/W/NV ............. 17
Binary Inputs ..................................................................................................................................................................................... 18
R200
Setup Button ......................................................................................BOOL ....................... R .......................... 18
R201
Binary Input 1 .....................................................................................BOOL ....................... R .......................... 18
R202
Binary Input 2 .....................................................................................BOOL ....................... R .......................... 18
Pulse Inputs ....................................................................................................................................................................................... 18
R208
Pulse Input Debounce Time .........................................................UINT16 ................... R/W/NV ............. 18
R210/11
Pulse Input 1 Count .........................................................................UINT32 ................... R/W/NV ............. 19
R212/13
Pulse Input 1 Active Elapsed Time .............................................UINT32 ................... R/W0 .................. 19
R216/17
Pulse Input 1 Preset .........................................................................UINT32 ................... R/W/NV ............. 19
R218/19
Pulse Input 1 Count Before Preset .............................................UINT32 ................... R/NV ................... 19
R220/21
Pulse Input 2 Count .........................................................................UINT32 ................... R/W/NV ............. 19
R222/23
Pulse Input 2 Active Elapsed Time .............................................UINT32 ................... R/W0 .................. 19
R226/27
Pulse Input 2 Preset .........................................................................UINT32 ................... R/W/NV ............. 19
R228/29
Pulse Input 2 Count Before Preset .............................................UINT32 ................... R/NV ................... 19
PowerPrint ......................................................................................................................................................................................... 20
R240
PowerPrint Alarm .............................................................................BOOL ....................... R .......................... 20
R241
PowerPrint Active .............................................................................BOOL ....................... R/W/NV ............. 20
R242/43
PowerPrint Frequency ....................................................................FLOAT ..................... R/W/NV ............. 20
R244/45
PowerPrint Frequency Tolerance ...............................................FLOAT ..................... R/W/NV ............. 21
R246/47
PowerPrint Voltage Tolerance .....................................................FLOAT ..................... R/W/NV ............. 21
R248/49
PowerPrint Voltage Angle Tolerance .......................................FLOAT ..................... R/W/NV ............. 21
Miscellaneous ................................................................................................................................................................................... 21
R276-91
Location String ..................................................................................ASCII ........................ R/W/NV ............. 21
R292-99
User Data .............................................................................................UINT16 ................... R/W/NV ............. 21
System Readings ............................................................................................................................................................................. 22
R310/11
Temperature .......................................................................................FLOAT ..................... R/W0 .................. 22
R380/81
Power Supply Voltage ....................................................................FLOAT ..................... R/W0 .................. 22
R400
Active Conditions .............................................................................UINT16 ................... R .......................... 23
R401
Previous Conditions ........................................................................UINT16 ................... R/W0 .................. 23
R410/11
Line Frequency ..................................................................................FLOAT ..................... R/W0 .................. 23
R420/21
Phase Average RMS Voltage ........................................................FLOAT ..................... R/W0 .................. 23
R450/51
Phase to Phase Average RMS Voltage ......................................FLOAT ..................... R/W0 .................. 24
R520/21
Phase Average RMS Current ........................................................FLOAT ..................... R/W0 .................. 24
R540/41
Phase Average Current Angle .....................................................FLOAT ..................... R/W0 .................. 24
R550/51
System Power Factor ......................................................................FLOAT ..................... R/W0 .................. 25
R600/09
Total Real Power ...............................................................................FLOAT ..................... R/W0 .................. 25
R610/11
Phase Average Real Power ...........................................................FLOAT ..................... R/W0 .................. 25
R620/21
Net Real Power ..................................................................................FLOAT ..................... R/W0 .................. 25
R640/41
Total Reactive Power .......................................................................FLOAT ..................... R/W0 .................. 25
R650/51
Phase Average Reactive Power ...................................................FLOAT ..................... R/W0 .................. 26
R660/61
Total Apparent Power ....................................................................FLOAT ..................... R/W0 .................. 26
R670/71
Phase Average Apparent Power .................................................FLOAT ..................... R/W0 .................. 26
R700/01
Total Real Energy ..............................................................................FLOAT* ................... R/W0/NV .......... 26
R720/21
System Real Energy .........................................................................FLOAT* ................... R/W0/NV .......... 26
R740/41
Total Reactive Energy .....................................................................FLOAT* ................... R/W/NV ............. 27
R760/61
Total Apparent Energy ...................................................................FLOAT* ................... R/W0/NV .......... 27
R800/01
Demand Real Power ........................................................................FLOAT ..................... R/W0 .................. 27
R820/21
Demand System Real Power ........................................................FLOAT ..................... R/W0 .................. 28
R840/41
Demand Reactive Power ...............................................................FLOAT ..................... R/W0 .................. 28
R860/61
Demand Apparent Power .............................................................FLOAT ..................... R/W0 .................. 28
R Phase Configuration ................................................................................................................................................................... 28
R1010-19 Phase Sensor Serial Number ........................................................ASCII ........................ R .......................... 28
R1020-29 Phase Sensor Model ........................................................................ASCII ........................ R .......................... 28
R1102
Present ..................................................................................................BOOL ....................... R .......................... 28
R1103
Status ....................................................................................................UINT16 ................... R .......................... 28
R1104
PowerPrint Identity Status ............................................................UINT16 ................... R .......................... 29
R1140/41 Voltage Rating ...................................................................................FLOAT ..................... R .......................... 29
R1142/43 Voltage Multiplier .............................................................................FLOAT ..................... R/W/NV ............. 29
R1144/45 PowerPrint Voltage ..........................................................................FLOAT ..................... R/W/NV ............. 29
R1146/47 PowerPrint Voltage Angle ............................................................FLOAT ..................... R/W/NV ............. 30
R1150/51 Current Rating ...................................................................................FLOAT ..................... R .......................... 30
R1152/53 Current Multiplier .............................................................................FLOAT ..................... R/W/NV ............. 30
R1154
Current Sensor Technology ..........................................................UINT16 ................... R .......................... 30
R1161
Power Multiplier Override .............................................................BOOL ....................... R/W ..................... 31
R1162/63 Power Multiplier ...............................................................................FLOAT ..................... R/W/NV ............. 31
R1192/93 Statistics Reset ...................................................................................UINT32 ................... R/W ..................... 31
R Phase Measurements ................................................................................................................................................................. 32
R1400
Active Conditions .............................................................................UINT16 ................... R .......................... 32
R1401
Previous Conditions ........................................................................UINT16 ................... R/W0 .................. 32
R1420/21 Phase RMS Voltage ..........................................................................FLOAT ..................... R/W0 .................. 32
R1440/41 Phase to Phase Voltage Angle .....................................................FLOAT ..................... R/W0 .................. 33
R1450/51 Phase to Phase RMS Voltage ........................................................FLOAT ..................... R/W0 .................. 33
R1520/21 Phase RMS Current ..........................................................................FLOAT ..................... R/W0 .................. 34
R1540/41 Phase Current Angle .......................................................................FLOAT ..................... R/W0 .................. 34
R1550/51 Phase Power Factor .........................................................................FLOAT ..................... R/W0 .................. 35
R1600/01 Phase Real Power .............................................................................FLOAT ..................... R/W0 .................. 35
R1640/41 Phase Reactive Power .....................................................................FLOAT ..................... R/W0 .................. 35
R1660/61 Phase Apparent Power ...................................................................FLOAT ..................... R/W0 .................. 36
R1700/01 Total Phase Real Energy .................................................................FLOAT* ................... R/NV ................... 36
R1740/41 Total Phase Reactive Energy ........................................................FLOAT* ................... R/NV ................... 36
R1760/61 Total Phase Apparent Energy ......................................................FLOAT* ................... R/NV ................... 37
R1800/01 Demand Real Power ........................................................................FLOAT ..................... R/W0 .................. 37
R1840/41 Demand Reactive Power ...............................................................FLOAT ..................... R/W0 .................. 38
R1860/61 Demand Apparent Power .............................................................FLOAT ..................... R/W0 .................. 38
S Phase................................................................................................................................................................................................. 38
R2000 – 2999 ............................................................................................................................................................................... 38
T Phase ................................................................................................................................................................................................ 38
R3000 – 3999 ............................................................................................................................................................................... 38
Functions ..................................................................................................................................................... 39
Data Types ......................................................................................................................................................................................... 39
0x03 Read Holding Registers ...................................................................................................................................................... 40
0x06 Write Single Register ........................................................................................................................................................... 41
0x08 Diagnostics ............................................................................................................................................................................. 42
0x00 | Return Query Data ....................................................................................................................................................... 42
0x10 Write Multiple Registers ..................................................................................................................................................... 43
0x11 Report Server ID .................................................................................................................................................................... 44
Appendix A: Common Registers ................................................................................................................ 45
Appendix B: Condition Flags Decoding ..................................................................................................... 47
Appendix C: Hex Conversions .................................................................................................................... 48
See Also:
152-0291
EM-RS485 Installation Instructions
154-0022
EM-RS485 BACnet Protocol Guide
Configuration
To CVTs
R S T
Line
Status
CVT
Status
POWER
GND
Device
Status
EM-RS485
RS485
Status
A (+)
COM
B (–)
Setup
Button
✓ Get In
✓ Get Out
→ Get Data
Congratulations on installing your new Senva EM-RS485 energy meter! This Modbus Protocol Guide assumes
the first stage of installation is complete, with the meter and any CVTs connected and powered. A green
Device Status indicates the meter is powered and ready. If not, refer to the separate Installation Instructions
before continuing. Now, only the network configuration remains between you and the data.
Each meter ships with a default Slave Address. To identify this address, add “100” to the last two digits of the
unique serial number printed on the label. When installing a meter on a dedicated Modbus network with no
other slave devices, the global address 255 (0xFF) may also be used (see R123).
3456
SN 123456
56
+100
156
Figure 1: Example Default Address
WARNING: Before connecting a meter to an existing network, ensure the default Slave Address will not
conflict! If necessary, select an alternate seed address with the Setup Button interface (see Installation
Instructions). Regardless of whether the default Slave Address, the global address, or an alternate seed
address is used, the meter may be programmed with any supported address after an initial connection is
established (see R123).
Leave the meter in the default factory mode for automatic network configuration:
•
•
•
•
Automatic Baud Rate detection (see R114, R124): 9600 – 115200 baud
Automatic Parity detection (see R116, R126): Even, Odd, No Parity
Automatic Data Bits detection (see R117, R127): 7, 8 Bits
Automatic Protocol detection (see R112, R122): Modbus RTU, ASCII
To begin automatic configuration, simply connect the RS485 terminals to an active Modbus network. An
active Modbus network consists of a Modbus master device that regularly polls at least one Modbus slave
(whether the slave replies or not).
IMPORANT: If a Modbus network has devices communicating with multiple baud rates and/or formats,
the automatic configuration result is unpredictable. Set the configuration manually with the Setup Button
interface (see Installation Instructions) before connecting the meter in such an environment.
Once connected, the meter observes RS485 activity to learn baud rate, serial format, and protocol. Without
activity, the meter cannot learn! The meter will not interfere with existing network traffic during the
observation phase. As configuration proceeds, the RS485 Status LED indicates progress with a combination
of color, blinking, and diagnostic condition codes (see Figure 2, and also the Installation Instructions).
Waiting For
Activity
Detecting
Baud Rate
Detecting
Protocol
Ready
Figure 2: Automatic Configuration Conditions
The RS485 Status LED turns green after at least one full frame successfully passes a CRC* integrity test.
Assuming no conflicts, the master can then use Modbus functions to query or configure registers.
The meter stores any discovered automatic configuration result in non-volatile memory and reloads them
whenever the meter resets (e.g. after power loss). The automatic configuration can be cleared by holding
down the Setup Button while resetting the meter (e.g. removing and reapplying power). User-configured
parameters will not be affected, but the meter must redetect any missing parameters before reestablishing
communication.
For permanent installations, the protocol configuration parameters (see R122 – R128) may be set to lock the
baud rate, format, and protocol. However, this will prevent the meter from adapting to future changes in
the network environment.
The EM-RS485 supports the following Modbus device functions:
•
•
*
0x08 Diagnostics
0x11 Report Server ID
Cyclical Redundancy Check
Holding Registers
The EM-RS485 supports the following Modbus functions:
• 0x03 Read Holding Registers
• 0x06 Write Single Register
• 0x10 Write Multiple Registers
In this document, Modbus addresses (beginning with “R”) represent raw protocol addresses. Some Modbus
conventions offset protocol addresses to form a register ID (e.g. 40001, Modicon notation). Refer to the
relevant controller documentation to determine any required programming offset for each installation.
Constructed registers (see Data Types) span multiple Modbus address. The notation RXX/YY specifies a pair
of aligned registers. RXX-YY specifies a range of consecutive registers, inclusive.
Unless otherwise specified, changes to RS485 parameters are effective after the response (i.e. a client must
maintain the original parameters for the remainder of the current transaction).
System Configuration
R102 Reset Reason
Returns a reason determined at the time of the last reset:
1.
2.
3.
4.
5.
UINT16
R
UINT16
R/NV
Configuration Reset (see R190)
(reserved)
Power Loss
(reserved)
Hardware Watchdog
R103 Reset Count
Returns a lifetime count of meter resets for any reason. The meter maintains this count in a
protected section of non-volatile memory unaffected by Configuration Reset (see R190).
At each reset, the meter restores accumulated energy, demand statistics, and pulse input counts
from non-volatile memory. However, all the analog statistics reset, plus the Up Time (see R104),
Energy Timestamp (see R174), and pulse input Elapsed Active Time (see R212).
R104/05 Up Time
UINT32
R
Returns the time since the last meter reset, in seconds. To determine the cause, read R102.
R111 Identify Meter
Sets the LED status interface into a visually identifiable mode:
0.
1.
BOOL
R/W
Inactive
Active
When set to Active, all status LEDs (see Installation Guide) begin slowly blinking green together.
This pattern is distinct from any other interface pattern the meter may display during normal
operation. The LEDs will remain in identify mode until the reset to Inactive or the Setup Button is
pressed.
This feature may be useful if several meters are connected on a single network and the association
between discovered device IDs and physical meters is uncertain.
Default: Inactive (normal LEDs)
R112 Auto Protocol
Sets the state of automatic protocol detection:
0.
1.
BOOL
R/W/NV
Inactive
Active
When Active, the RS485 receiver initially allows frames of any supported protocol. On establishing
confidence in a particular protocol (about 10 consecutive frames of the same type), this becomes
the preferred RS485 Protocol (see R122).
Generally, having a preferred protocol disallows other protocols. This reduces uncertainty in the
unlikely event that a particular frame or sequence could be interpreted as more than one protocol.
However, should the protocol really change (e.g. by moving the meter to a different network), the
meter will eventually lose confidence in the preferred protocol. After temporarily allowing all
protocols, automatic protocol detection will establish a new preference. To avoid the delays
associated with changing protocol, set the RS485 Protocol to some option that permanently allows
multiple protocols.
When changing this value, the meter keeps the current RS485 Protocol to avoid communication
loss. Setting Inactive disables further automatic protocol changes and only allows the protocol(s)
specifically set in RS485 Protocol.
Default: Active
R114 Auto Baud Rate
Sets the state of automatic baud rate detection:
0.
1.
BOOL
R/W/NV
Inactive
Active
When Active, the meter may automatically change the Baud Rate (see R124) in response to RS485
communication errors. When changing this value, the meter always keeps the current Baud Rate to
avoid communication loss.
Default: Active
R116 Auto Parity
Sets the state of automatic parity detection:
0.
1.
BOOL
R/W/NV
Inactive
Active
When Active, the meter may automatically change the Parity (see R126) in response to RS485
communication errors. When changing this value, the meter always keeps the current Parity to
avoid communication loss.
Default: Active
R117 Auto Data Bits
BOOL
R/W/NV
Sets the state of automatic data bits detection:
0.
1.
Inactive
Active
When Active, the meter may automatically change the Data Bits (see R127) in response to RS485
communication errors. When changing this value, the meter always keeps the current Data Bits to
avoid communication loss.
Default: Active
R118 Auto Stop Bits
Sets the state of automatic stop bits:
0.
1.
BOOL
R/W/NV
UINT16
R/W/NV
Inactive
Active
Returns Active when Stop Bits is Auto (see R128).
Default: Active
R122 RS485 Protocol
Sets the communication protocol(s):
1.
2.
3.
4.
Auto
BACnet
Modbus RTU
Modbus ASCII
5.
6.
7.
8.
BACnet and Modbus RTU
BACnet and Modbus ASCII
Modbus RTU and ASCII
Any Protocol
If Auto Protocol is Active (see R112), returns the auto-detected protocol (typically Modbus RTU or
Modbus ASCII). Otherwise, returns the user-configured protocol option.
Setting any value other than Auto also sets Auto Protocol to Inactive. Setting Auto copies any
previously set protocol option to the automatic protocol detector, and sets Auto Protocol to Active.
Setting an option with multiple protocols (5 – 8) reduces the Auto Protocol re-detection delay.
Default: Auto
R123 Slave Address
UINT16
R/W/NV
Sets the Modbus slave address, 1 – 254.
Assign unique addresses to each Modbus slave device on a network. The Modbus specification
only allows slave addresses 1 – 247. Although the meter supports the assignment of reserved
addresses 248 – 254, undefined network behavior may result.
In the default configuration, returns the factory default slave address (see Configuration).
Otherwise, returns the user-configured slave address. Before setting the address, ensure that the
new address will not conflict with any other slave devices on the Modbus network.
In addition to the assigned slave address, the meter will respond to Modbus commands addressed
to the global address 255 (0xFF). Only use this address if the meter is installed on a dedicated
Modbus network with no other slave devices.
Default: Varies
R124/25 RS485 Baud Rate
UINT32
R/W/NV
Sets the communication baud rate, 1200 – 460800.
When Auto Baud Rate is Active (see R114), returns the auto-detected baud rate (see Configuration).
Otherwise, returns the user-configured baud rate.
Almost by definition, successfully reading baud rate implies a correct value, with no further action
required. However, when transitioning a Modbus network to a new baud rate, it may be useful to
remotely configure the new baud rate before transitioning the gateway/controller. Setting any
user-configured baud rate also sets Auto Baud Rate to Inactive.
WARNING: The meter provides no facility to revert the baud rate remotely. Once written, the
meter will lose communication until the client baud rate matches the new configuration.
Default: Varies
R126 RS485 Parity
UINT16
Sets the communication parity:
1.
2.
3.
4.
R/W/NV
Auto
No Parity
Odd Parity
Even Parity
If Auto Parity is Active (see R116), returns the auto-detected parity (typically Even Parity for Modbus).
Otherwise, returns the user-configured parity option.
Setting any value other than Auto sets Auto Parity to Inactive. Setting Auto sets Auto Parity to Active,
but keeps the current parity option to avoid loss of communication.
Setting Auto copies any previously set parity option to the automatic parity detector and sets Auto
Parity to Active.
Default: Auto
R127 RS485 Data Bits
UINT16
Sets the communication data bits:
1.
2.
3.
R/W/NV
Auto
7 Bits
8 Bits
If Auto Data Bits is Active (see R117), returns the automatically detected number of data bits
(typically 8 Bits for Modbus RTU, 7 Bits for Modbus ASCII). Otherwise, returns the user-configured
data bits option.
Setting any value other than Auto sets Auto Data Bits to Inactive. Setting Auto sets Auto Data Bits to
Active, but keeps the current data bits option to avoid loss of communication.
Default: Auto
R128 RS485 Stop Bits
UINT16
Sets the communication stop bits:
1.
2.
3.
4.
R/W/NV
Auto
1 Bit
1.5 Bits
2 Bits
Always returns the user-configured stop bits option. When set to Auto, Modbus dynamically
provides the most compatible configuration:1 Bit for data receive and 2 Bits for data transmit.
The Auto Stop Bits (see R118) value follows this value. Setting any value other than Auto sets Auto
Stop Bits to Inactive. Setting Auto sets Auto Stop Bits to Active.
Default: Auto
R133 Temperature Units
Sets the preferred units for temperature values:
1.
2.
UINT16
R/W/NV
Degrees Fahrenheit (°F)
Degrees Celsius (°C)
Saved statistical values automatically convert when the selected unit changes.
Default: Degrees Fahrenheit
EM-RS485 Modbus Protocol Guide
Page 11 of 48
154-0023-0A-DRAFT
R134 Smoothed Temperature Response Time
UINT16
Sets the step response time for smoothed temperature (see R312), in seconds.
R/W/NV
Across all groups, the various Smoothed values track the instantaneous measurement after the
application of a first-order exponential function. This low pass filter attenuates fast changes, such
as the inrush current of a large industrial motor. Smoothed values may provide a stable baseline
measurement but will always lag the instantaneous measurement (see Figure 3A).
Formally, response time sets the time required for a Smoothed value to complete 90% of the
transition after an ideal step between two stable values (see Figure 3B).
instantaneous
90%
smoothed
A: General Smoothing
τ
B: Ideal Step Response
Figure 3: Smoothed Response Time
During periods of invalid measurement, Smoothed values return 0 (undefined). The resumption of
valid measurements momentarily suppresses the smoothing function while the value stabilizes.
Default: 30 seconds
R142 Smoothed Frequency Response Time
UINT16
R/W/NV
UINT16
R/W/NV
UINT16
R
Sets the step response time (see R134) for smoothed Frequency (see R412) and Voltage Angle
(e.g. R1442), in seconds.
Default: 60 seconds
R144 Smoothed Voltage Response Time
Sets the step response time (see R134) for smoothed RMS Voltage (e.g. R1422), in seconds.
Default: 10 seconds
R152 System Current Sensor Technology
Returns the overall current sensor technology of the CVT(s) installed with a meter. This value is
provided in anticipation of future CVT technology upgrades:
1.
2.
3.
4.
5.
Unknown Technology
Conflicted Technology
Multiple Technology
Rogowski Coil
Current Transformer
This value derives from the combination of the Current Sensor Technology (see R1154) of each CVT.
All CVTs installed with a single meter must be compatible for proper operation.
Read only. At EM-RS485 launch, all Senva CVTs are based on Rogowski Coil technology. If no CVTs
are installed, returns Unknown Technology.
EM-RS485 Modbus Protocol Guide
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154-0023-0A-DRAFT
R153 Angle Units
Sets the preferred units for angle values:
1.
2.
UINT16
R/W/NV
Degrees
Radians
Saved statistical values automatically convert when the selected unit changes.
Default: Degrees
R154 Smoothed Current Response Time
UINT16
R/W/NV
Sets the step response time (see R134) for smoothed RMS Current (e.g. R1522), Current Angle
(e.g. R1542), and Power Factor (e.g. R1552), in seconds.
Default: 2 seconds
R161 System Phase Selection
Sets the phase selection mask for system measurements:
1.
2.
3.
4.
UINT16
R/W/NV
3 Phase
R Phase and S Phase
S Phase and T Phase
R Phase and T Phase
System measurements, including phase averages (e.g. R420) and accumulations (e.g. R700), are
based on the selected phases only. Set this value in case of a split system (e.g. 2 CVTs measuring a
2-phase system input with a third CVT measuring a separate branch load). There are no equivalent
options for single phase, as individual phase measurements are always accessible.
For consistency, consider resetting the system statistics (see R192) after changing this setting.
Default: 3 Phase
R162 Power Spectrum
UINT16
Sets the bandwidth of real and reactive power and energy measurements:
1.
2.
R/W/NV
Wideband
Fundamental
Generally, harmonic components are the result of non-linear distortions in the generator or the
load. In Wideband mode, measurements include power of all harmonic components (e.g. 3rd, 5th),
up to the cutoff frequency (see Installation Instructions). In Fundamental mode, measurements
include only power in the fundamental Frequency (see R410).
NOTE: Harmonic power requires matched frequency components in the spectrum of both voltage
and current. For example, given a 5th harmonic of current, there must be a corresponding 5th
harmonic of voltage. Otherwise, even though distortion power increases, the real and reactive
components of power cancel leaving only the power in the fundamental.
For consistency, consider resetting accumulated energy (see R192) after changing this setting.
Default: Wideband
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R163 Power Units
UINT16
R/W/NV
Sets the preferred units for power and demand power values:
1.
2.
3.
Kilowatts
Watts
Megawatts
Saved statistical values, included maximum demand power, automatically convert when the
selected unit changes.
The options specify real power units only. Reactive and apparent power always follow the real
power scale, as shown in each column:
Real Power
Reactive Power
Apparent Power
Relative Scale = 1.0
W (Watts)
VAR (Volt-Amps Reactive)
VA (Volt-Amps)
1,000
kW
kVAR
kVA
1,000,000
MW
MVAR
MVA
Default: Kilowatts
R164 Smoothed Power Response Time
UINT16
R/W/NV
BOOL
R/W/NV
Sets the step response time (see R134) for smoothed Power (e.g. R1602), in seconds.
Default: 2 seconds
R170 Energy Data Type
Sets the data type when reading energy accumulators (e.g. R700):
0.
1.
Floating Point
Unsigned Integer
Both modes read from the same internal register, with a fixed capacity of ±1.0 TWh. Changing the
mode does not affect the accumulated energy in any way. Reading a register in either mode always
returns a value scaled to the system Energy Units (see R173).
In Floating Point mode, energy registers return a floating point value, possibly up to the full range of
the accumulator. By automatically scaling the return value, this value cannot overflow unless the
internal register also overflows. However, the resolution will gradually degrade as more energy
accumulates, making it harder to observe small incremental changes.
In Unsigned Integer mode, energy registers return an unsigned integer, 0 – 999999. When the
energy exceeds the upper bound, the value wraps to 0 (modulo arithmetic). This view most closely
corresponds to traditional analog meters, with the primary
advantage that the energy resolution is fixed at 1 Energy Unit.
If energy overflows, the overflow energy may still be read by
setting the next larger Energy Unit. Negative power causes net
accumulators (e.g. R1706) to run backwards; underflow causes
the value to wrap from 0 backwards to 999999.
Default: Floating Point
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R173 Energy Units
Sets the preferred units for accumulated energy values:
1.
2.
3.
UINT16
R/W/NV
Kilowatt Hours
Watt Hours
Megawatt Hours
Accumulated energy automatically converts with no loss when the selected unit changes.
The options specify real energy units only. Reactive and apparent energy always follow the real
energy scale, as shown in each column:
Real Energy
Reactive Energy
Apparent Energy
Relative Scale = 1.0
Wh (Watt hours)
VARh (Volt-Amp Reactive hours)
VAh (Volt-Amp hours)
1,000
kWh
kVARh
kVAh
1,000,000
MWh
MVARh
MVAh
FLOAT
R
Default: Kilowatt Hours
R174/75 Energy Timestamp
Returns a high resolution timestamp, 0 – 4194304 milliseconds (222 – 1, about 1 hour).
The timestamp value updates atomically with the various energy accumulators. If read just before
or after a block of one or more energy measurements, this timestamp may be useful for calculating
accurate average power from differential energy:
𝑃𝐴𝑉𝐺 =
∆𝐸 𝐸2 − 𝐸1
=
𝑡2 − 𝑡1
∆𝑡
R181 Demand Window Synchronization
Sets the synchronization mode for the demand window:
1.
2.
3.
4.
5.
6.
UINT16
R/W/NV
No Synchronization
Setup Button
Binary Input 1 (falling)
Binary Input 1 (rising)
Binary Input 2 (falling)
Binary Input 2 (rising)
Selecting any of the synchronization sources allows the internal window to be aligned to some
external reference (Figure 4B). When a synchronization event is detected, the current window ends
immediately and a new window begins. Synchronization events occur exactly once when the
selected condition is detected. Synchronization cannot re-occur until the condition is removed and
redetected, no matter how long it may be maintained.
In No Synchronization mode, the Elapsed Demand Window (see R184) counts time continuously, only
restarting if the meter itself restarts (Figure 4A). When the counter reaches the full Demand Window
Time (see R183), the current demand window ends and a new window begins.
In Setup Button (see R200) mode, synchronization occurs as soon as the button is pressed. The
Setup Button always performs its normal function. If there are any active conditions, it may be
necessary to press the button a second time to exit diagnostic mode (see Installation Instructions).
In this case, the second press would trigger a second synchronization.
In Binary Input (see R201, R202) mode, Falling Edge synchronization occurs when an external contact
pulls the pulse input to GND (active low, see Figure 6). Rising Edge synchronization occurs in the
opposite condition, when an external contact opens. The Debounce Time (see R208) may delay the
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synchronization up to 250 milliseconds after the transition. This mode may be useful to align
demand windows with a utility meter that provides a regular synchronization pulse.
For Full Synchronization, relying exclusively on an external trigger, disable the internal window time
by setting the Demand Window Time to 0 minutes (Figure 4C).
W
W
W
W
A: No Synchronization
T
S
W
B: Basic Synchronization
S
S
S
S
C: Full Synchronization
Figure 4: Synchronization Modes
NOTE: Consider synchronizing when the average power is typically light. When a synchronization
event is detected, it makes no difference how much or little time has elapsed in the current
window. Average power may be more volatile if the window has only just started, being measured
over a shorter period of time.
Default: No Synchronization
R183 Demand Window Time
UINT16
R/W/NV
Sets the maximum demand window time, 0 – 1440 minutes.
The demand measurements (see R1800) measure average power within a windowed period.
Every time the Elapsed Demand Window time (see R184) reaches this limit, the current window ends
and a new window starts.
If set to 0 minutes, the window time is unlimited (see Error! Reference source not found.). In this
case, new windows are only started by external synchronization (see R181) or software
synchronization (see R184).
Default: 15 minutes
R184/85 Elapsed Demand Window
UINT32
Returns the time since the beginning of the current demand window, in minutes.
R/W0
The demand measurements (see R1800) measure average power within a windowed period.
This value resets to 0 at the beginning of each new demand window (see Error! Reference source
not found.). Writing 0 at any time automatically starts a new window (software synchronization).
R186/87 Demand Window Count
UINT32
R/NV
Returns the number of completed demand windows. Any demand window at least 1 second long
counts, regardless of whether the window was defined by external synchronization (see R181),
software synchronization (see R184), or elapsed time (see R183). Resetting all or a portion of the
demand statistics (see R192, R1192) does not automatically start a new demand window.
The system and all phase demand values update together (e.g. R1800), so this count can serve as a
unique key to identify each new batch of demand statistics (e.g. for logging).
Resets to 0 only when the system and all phase demand statistics are reset together (see R192).
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R190/91 Reset Meter Configuration
UINT32
W
Always returns 0. Write the reset key to reset the meter to factory defaults.
WARNING: The entire non-volatile configuration will be permanently lost; previous configurations
cannot be recovered. This includes accumulated energy, demand statistics, and pulse input counts.
This also includes the current RS485 serial format and Slave Address. The only parameters not
affected are the Reset Count (see R103) and the Energy Reset Count (see R194).
After a configuration reset, the meter itself will reset and re-learn the current baud rate, serial
format, and protocol (see Configuration).
Write 9699690 to reset the meter to factory defaults.
R192/93 Reset Meter Statistics
UINT32
W
Always returns 0. Write one of the following keys to reset some or all of the phase statistics. Writing
any other value results in an error response.
WARNING: Selected statistics will be permanently lost; previous records cannot be recovered.
System statistics ONLY:
•
•
•
•
Write 4765089 to reset analog statistics (R410 – R678: Minimum, Maximum, Average)
Write 5338209 to reset demand statistics (R800 – R866: Minimum, Maximum)
Write 6647201 to clear accumulated energy (R700 – R766: All Registers)
Write 5811297 to reset all system statistics
System and all phases R/S/T:
•
•
•
•
Write 7648701 to reset all analog statistics
Write 7566461 to reset all demand statistics
Write 6909373 to clear all accumulated energy
Write 4762749 to reset all statistics
Phase R/S/T statistics may also be reset individually (see R1192). Analog statistics automatically
reset whenever the meter itself resets (see R103). Individual analog and demand statistics may also
be automatically reset when Auto Reset Statistics is Active (see R195).
Resetting any subset of accumulated energy increments the Energy Reset Count (see R194).
R194 Energy Reset Count
UINT16
R/NV
Returns the number of times accumulated energy has been reset. Counts “1” for every full or partial
energy reset key written (see R192, R1192), regardless of the actual energy accumulation.
This value may be useful for auditing, since the meter maintains this count in a protected section of
non-volatile memory unaffected by Configuration Reset (see R190)
R195 Auto Reset Statistics
BOOL
R/W/NV
Setting “1” activates Reset After Read mode, where reading an individual statistical measurement
also resets it, as if it had been followed by a write of 0 (see System Readings).
Auto reset mode may be useful in some low-overhead remote logging installations.
WARNING: When using Auto Reset Statistics as part of a periodic process, ensure there are no extra
reads generated between logging intervals. Otherwise, the resulting records may reflect only a
portion of the intended interval.
Default: Inactive
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Binary Inputs
R200 Setup Button
BOOL
Returns “1” when the Setup Button (see Installation Instructions) is pressed.
R
This value may be useful for protocol testing. Regardless of the value returned, the Setup Button
always performs its normal function for diagnostics and configuration.
R201 Binary Input 1
R202 Binary Input 2
Returns the current stable state of the corresponding
pulse input (active low; see Installation Instructions). The
Pulse Input Debounce Time (see R208) sets the minimum
stability requirement for each transition.
BOOL
BOOL
This value may be useful if the pulse input is connected to
a discrete contact, such as an alarm, to trigger additional
controller actions. If so, the corresponding Pulse Input
count (see R210, R220) may be ignored.
Pulse
Input
One of the binary inputs may be selected as the source for
Demand Window Synchronization (see R181).
GND
R
R
Remote
Contact
Figure 5: Binary Input Wiring
Pulse Inputs
R208 Pulse Input Debounce Time
UINT16
R/W/NV
Sets the delay time for each input transition before registering a new state, 0 – 255 milliseconds.
This suppresses glitches in the input, such as might be generated by a mechanical relay or electrical
interference (see Figure 6). Affects both the Pulse Inputs (see R210, R220) and corresponding Binary
Inputs (see R201, R202).
Raw Input
Debounced
Figure 6: Debouncing Delay
If possible, set the debounce time to 50% of the expected minimum pulse time. Setting 0 disables
debouncing: new input states register immediately, but the count may be noisy.
IMPORTANT: Because each pulse must have both a high and low interval, the maximum pulse rate
will be 1/2 the equivalent rate of a single debounce time. For example, a 1 millisecond debounce
time permits a maximum pulse rate of 500 Hz. Reduce the maximum pulse rate further when the
duty cycle of the input is not 50%.
Default: 10 milliseconds (50 Hz)
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R210/11 Pulse Input 1 Count
UINT32
R/W/NV
Returns the count of pulses received at the respective pulse terminal (see Installation Instructions).
NOTE: The corresponding Binary Inputs (R201/R202) track the instantaneous state of the terminal.
Each count represents a pair of input edges (active low), registered on the leading (falling) edge.
At each transition, the input delays by the Debounce Time (see R208).
1
2
3
4
Figure 7: Pulse Input Counting
The maximum count is 4294967295 (232 – 1) before the value overflows to 0.
R212/13 Pulse Input 1 Active Elapsed Time
UINT32
R/W0
R216/17 Pulse Input 1 Preset
UINT32
R/W/NV
Returns the total time, in seconds, that the pulse input has been active (active low) since the last
meter reset. Write 0 to reset the count.
Write this register to initialize the pulse input counter. This may be useful for continuity when the
EM-RS485 replaces an existing meter.
When written, the meter first copies the original Pulse Input Count (see R210) to Count Before Preset
(see R218). Then, the meter sets both Pulse Count and Preset (this register) to the new value. These
steps are performed atomically, which allows the Pulse Count to be modified while accurately
accounting for every input pulse.
Default: 0
R218/19 Pulse Input 1 Count Before Preset
UINT32
R/NV
UINT32
UINT32
UINT32
UINT32
R/W/NV
R/W0
R/W/NV
R/NV
Returns the Pulse Count (see R200) saved during the last write to Pulse Input Preset (see R216).
Default: 0
R220/21
R222/23
R226/27
R228/29
Pulse Input 2 Count
Pulse Input 2 Active Elapsed Time
Pulse Input 2 Preset
Pulse Input 2 Count Before Preset
Pulse Input 2 holding register functions match Pulse Input 1.
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PowerPrint
R240 PowerPrint Alarm
Returns “1” when any of the PowerPrint conditions are active:
•
•
•
•
•
BOOL
R
Frequency Drift (see R242, R400)
Phase Angle Drift (see R1146, R400)
Brown Out Voltage (see R1144, R1400)
Surge Voltage (see R1144, R1400)
Unexpected Sensor (see R1104, R400)
Review associated conditions and measurements to determine the source of any anomaly and
appropriate actions. Once triggered, the Alarm remains Active for as long as any PowerPrint
condition remains active, plus an additional 10 seconds.
R241 PowerPrint Active
Sets the overall state of the PowerPrint feature:
0.
1.
BOOL
R/W/NV
Inactive
Active
Returns Active if at least one of the PowerPrint reference parameters has been set.
•
•
•
•
Frequency (see R242)
Voltage (see R1144)
Voltage Angle (see R1146)
Identity (see R1104)
Setting Inactive clears all of the reference parameters at once. Setting Active while Inactive
initializes PowerPrint (if already Active, setting Active has no effect). When activated this way,
PowerPrint initializes all of the reference parameters at once:
•
•
•
•
Sets the expected frequency to exactly 50 Hz or 60 Hz if the measured Frequency (see R410) is
within the Frequency Tolerance (see R244); otherwise leaves expected frequency undefined.
Sets the expected voltage for each phase equal to the measured RMS Voltage (see R1420) if the
measured voltage is not detecting the Phase Loss condition.
Sets the expected voltage angle between each phase and the next equal to the measured
angle (see R1440) if neither phase is detecting the Phase Loss condition.
Sets the reference identity for each phase CVT if the Status (see R1103) is No Fault Detected.
May return a BACnet Internal Error if no PowerPrint parameters could be set (e.g. no CVTs installed).
Default: Inactive
R242/43 PowerPrint Frequency
FLOAT
R/W/NV
Sets the expected PowerPrint frequency. If set to any non-zero value, and the Frequency (see R410)
differs from expected by more than the Frequency Tolerance (see R244), then the Frequency Drift
condition (see R400) will be set.
Set the expected frequency by writing this value directly, or by initializing PowerPrint (see R241).
Default: 0 Hz (undefined)
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R244/45 PowerPrint Frequency Tolerance
FLOAT
R/W/NV
FLOAT
R/W/NV
FLOAT
R/W/NV
ASCII
R/W/NV
Sets the tolerance of the PowerPrint Frequency (see R242), 0 – 10 Hz.
Default: 0.2 Hz
R246/47 PowerPrint Voltage Tolerance
Sets the tolerance of the PowerPrint Voltage (see R1144) for all phases, 0 – 100% as a ratio of the
target voltage. For example, given a target voltage of 240 V and a tolerance of 10%, PowerPrint
expects voltages of 216 – 264 V.
Default: 10%
R248/49 PowerPrint Voltage Angle Tolerance
Sets the tolerance of the PowerPrint Voltage Angle (see R1146) for all pairs of phases, 0– 180°.
The default units are Degrees (see R153).
Default: 30°
Miscellaneous
R276-91 Location String
Null terminated ASCII string to be appended to the Server ID, 0 – 31 characters. Consecutive
characters are appended to the fixed portion of the Server ID until the first null (0) is found.
Although registers after the first null won’t print, they may still be used for arbitrary storage.
Default: “<location>”
R292-99 User Data
UINT16
R/W/NV
Arbitrary data storage, 0 – 65535.
Any value written may be read back later.
Default: 0
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System Readings
For statistical purposes, input values are organized into groups. By convention, the primary value topping
each group provides the most accurate, up-to-date reading possible. Secondary values within a group
provide derivative measurements updated over time that may partially replace some simple logging
functions with less setup and bandwidth overhead. Typical secondary values include:
•
•
•
•
Smoothed: Returns the value after applying a first-order exponential filter (see R134).
Minimum: Returns the single lowest valid reading taken since last reset.
Maximum: Returns the single highest valid reading taken since last reset.
Average: Returns the average of all valid readings taken since last reset.
Once recorded, there are a few methods to reset statistics records (Minimum, Maximum, Average):
•
•
•
Manually for a single value, by writing 0 to the register (W0 in the Access Legend).
Manually for multiple value, by writing one of the Statistics Reset keys (see R192, R1192).
Automatically for single values, by configuring Auto Reset Statistics (see R195).
Regardless of method, general value record(s) revert to the primary value (see Figure 8) on reset.
Demand record(s) (Minimum, Maximum) remain 0 until the current window ends (see R1800, R186).
Maximum
Reset 1
Reset 2
Minimum
Figure 8: Reset Behavior
R310/11 Temperature
FLOAT
R/W0
Returns the approximate ambient temperature at the meter’s installed location. The default units
are °F (see R133). The meter compensates small drifts in CVT voltage and current measurements
(the meter assumes CVT temperature is similar to meter temperature, see Installation Instructions).
If the temperature is beyond the meter’s rated specifications, the Device Status LED will indicate the
corresponding Temperature Limit warning condition (see Installation Instructions).
The default smoothed value response time is 30 seconds (see R134).
R312/13 Instantaneous ● R314/15 Minimum ● R316/17 Maximum ● R318/19 Average
R380/81 Power Supply Voltage
FLOAT
R/W0
Returns the approximate working voltage provided to the meter’s low voltage power supply, in V.
The voltage reported is an internal voltage after rectification and reverse input protection (typically
1.0 – 2.0 V less than the peak supply voltage).
The meter requires 12.0 VDC minimum for full operation. If the supply voltage drops below this
threshold, the meter anticipates a power loss and saves the configuration and accumulated energy
to non-volatile memory. However, if the power loss proves only partial, the meter may continue to
operate at the reduced voltage. In this state, accumulating energy may be lost if the meter has
insufficient reserve power if/when power loss finally occurs. The Device Status LED will indicate the
corresponding Low Supply Voltage warning condition (see Installation Instructions).
R382/83 Instantaneous ● R384/85 Minimum ● R386/87 Maximum ● R388/89 Average
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R400 Active Conditions
UINT16
Returns an encoded set of flags representing active system conditions:
•
•
•
•
•
Mismatched Voltage (see R1450)
Reverse RST Order (see R1440)*
Not 3-Phase (see R1440)*
Frequency Drift (see R1420)**
Phase Drift (see R1440)**
BIT [5]
BIT [6]
BIT [7]
BIT [12]
BIT [15]
R
32
64
128
4096
32768
The conditions reflect the near-real-time system status observed over the previous 1 – 2 seconds.
The Line Status LED also indicates the active conditions (see Installation Instructions).
If no CVTs are installed, always returns “0”. To decode a set of condition flags, see Appendix B.
*Conditions only reported when the PowerPrint Voltage (see R1144) is undefined.
**Conditions only reported after activating the corresponding PowerPrint feature(s).
R401 Previous Conditions
UINT16
R/W0
Returns an encoded set of flags representing all active and historical system conditions. Equivalent
to Active Conditions (see R400), except that conditions remain in the set until manually cleared.
Write “0” to clear historical flags (set in R401 but no longer set in R400). Flags are also cleared when
the meter resets. Active flags (still set in R400) cannot be effectively cleared, since they will be
immediately re-set.
R410/11 Line Frequency
FLOAT
R/W0
Returns the fundamental AC line frequency 𝒇, in Hz. If there are no CVTs connected, or all of the
CVTs measure Phase Loss conditions (see R1420), returns 0 Hz.
With a PowerPrint Frequency target set (see R242), frequency variations may set the Frequency Drift
condition (see R400).
The default smoothed value response time is 60 seconds (see R142).
R412/13 Instantaneous ● R414/15 Minimum ● R416/17 Maximum ● R418/19 Average
R420/21 Phase Average RMS Voltage
FLOAT
R/W0
Returns the average 𝑽 of the RMS Voltage (see R1420) of all valid system phases. If there are no
valid phases, returns 0 V.
For average calculations in general, a valid system phase must:
•
•
•
Be included in the System Phase Selection (see R161),
Have a CVT Status of No Error (see R1103), and
Not be detecting the Phase Loss condition (see R1420).
The default smoothed value response time is 10 seconds (see R144).
R422/23 Instantaneous ● R424/25 Minimum ● R426/27 Maximum ● R428/29 Average
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R450/51 Phase to Phase Average RMS Voltage
FLOAT
R/W0
Returns the average 𝑽𝑷𝑷 of the Phase to Phase RMS Voltage (see R1450) between valid system
phases (as defined by R420). If there are exactly two valid phases, the average collapses to the
single reading between them. If there are less than two valid phases, returns 0 V.
As with individual phase to phase voltages measurements, the average is valid only when CVTs
share a common neutral connection and all phases have the same frequency (the meter does not
check either condition).
The default smoothed value response time is 10 seconds (see R144).
R452/53 Instantaneous ● R454/55 Minimum ● R456/57 Maximum ● R458/59 Average
R520/21 Phase Average RMS Current
FLOAT
R/W0
Returns the average 𝑰 of the RMS Current (see R1520) of valid system phases (as defined by R420). If
there are no valid phases, returns 0 A.
The default smoothed value response time is 2 seconds (see R154).
R522/23 Instantaneous ● R524/25 Minimum ● R526/27 Maximum ● R528/29 Average
R540/41 Phase Average Current Angle
FLOAT
R/W0
Returns the average 𝝋 of the Current Angle (see R1540) of valid system phases. The default units
are Degrees (see R153), normalized between –180 and +180°.
In addition to the standard criteria (as defined by R420), valid system phases must have sufficient
load power to give a stable measurement (see R1600, No Load condition). Returns 0° if there are no
valid phases.
The average of angles with a total sweep approaching 180° or more (see Figure 9) is indeterminate.
In such cases, also returns 0°.
An indeterminate average often indicates that the CVT voltage leads or current sensor loop were
installed backwards. If so, a negative multiplier (see R1142, R1152) may restore the result.
+Real
–Real
+Reactive
+Real
–Real
+Real
+Reactive
–Real
+Reactive
–Reactive
–Reactive
–Reactive
A: Sweep = 60° ✔
B: Sweep = 135° ✔
C: Sweep = 205° ✘
Figure 9: Swept Current Angle
The default smoothed value response time is 2 seconds (see R154).
R542/43 Instantaneous ● R544/45 Minimum ● R546/47 Maximum ● R548/49 Average
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R550/51 System Power Factor
FLOAT
R/W0
� of the valid system phases (as defined by R420).
Returns the true (apparent) power factor 𝒑𝒇
Unlike an arithmetic average, the system power factor weights
the Real Power (see R620) and Apparent Power (see R660) of
each phase (see Figure 11). This definition keeps lightly loaded
phases with relatively poor power factor from introducing
excessive distortion in the result.
� =
𝒑𝒇
R
S
𝑷𝑵𝑬𝑻
𝑺
T
If negative, the system export power exceeds the import power.
If the power in two phases flows in opposite directions, the
real components cancel, reducing the overall power factor.
Figure 10: System Power Factor
The default smoothed value response time is 2 seconds (see R164).
R552/53 Instantaneous ● R554/55 Minimum ● R556/57 Maximum ● R558/59 Average
R600/09 Total Real Power
FLOAT
R/W0
Returns the absolute sum 𝚺𝑷 of the Real Power (see R1600) of valid system phases (as defined by
R420). The default units are kW (see R163).
The default smoothed value response time is 2 seconds (see R164).
R602/03 Instantaneous ● R604/05 Minimum ● R606/07 Maximum ● R608/09 Average
R610/11 Phase Average Real Power
FLOAT
R/W0
Returns the absolute average 𝑷 of the Real Power (see R1600) of valid system phases (as defined by
R420). The default units are kW (see R163).
The default smoothed value response time is 2 seconds (see R164).
R612/13 Instantaneous ● R614/15 Minimum ● R616/17 Maximum ● R618/19 Average
R620/21 Net Real Power
FLOAT
R/W0
Returns the signed sum 𝑷𝑵𝑬𝑻 of the Real Power (see R1600) of valid system phases (as defined by
R420). The default units are kW (see R163). Negative values indicate that overall export power
exceeds import power.
The default smoothed value response time is 2 seconds (see R164).
R622/23 Instantaneous ● R624/25 Minimum ● R626/27 Maximum
R628/29 Overall Average ● R630/31 Import Average ● R632/33 Export Average
R640/41 Total Reactive Power
FLOAT
R/W0
Returns the absolute sum 𝚺𝑸 of the Reactive Power (see R1640) of valid system phases (as defined
by R420). The default units are kVAR (see R163).
The default smoothed value response time is 2 seconds (see R164).
R642/43 Instantaneous ● R644/45 Minimum ● R646/47 Maximum ● R648/49 Average
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R650/51 Phase Average Reactive Power
FLOAT
R/W0
Returns the absolute average 𝑸 of the Reactive Power (see R1640) of valid system phases (as defined
by R420). The default units are kVAR (see R163).
The default smoothed value response time is 2 seconds (see R164).
R652/53 Instantaneous ● R654/55 Minimum ● R656/57 Maximum ● R658/59 Average
R660/61 Total Apparent Power
FLOAT
R/W0
Returns the absolute sum 𝚺𝑺 of the Apparent Power (see R1660) of valid system phases (as defined
by R420). Always positive. The default units are kVA (see R163).
The default smoothed value response time is 2 seconds (see R164).
R662/63 Instantaneous ● R664/65 Minimum ● R666/67 Maximum ● R668/69 Average
R670/71 Phase Average Apparent Power
FLOAT
R/W0
Returns the absolute average 𝑺 of the Apparent Power (see R1660) of valid system phases (as
defined by R420). The default units are kVA (see R163).
The default smoothed value response time is 2 seconds (see R164).
R672/73 Instantaneous ● R 674/75 Minimum ● R676/77 Maximum ● R678/79 Average
R700/01 Total Real Energy
FLOAT*
R/W0/NV
FLOAT*
R/W0/NV
Returns the combined energy of the system phases (see R161). The default type is Floating Point
(see R170). The default units are kWh (see R173). For a 3 Phase installation:
Total = R1700 + R2700 + R3700
Import = R1702 + R2702 + R3702
Export = R1704 + R2704 + R3704
Net = R1706 + R2706 + R3706
R702/03 Import ● R704/05 Export ● R706/07 Net
R720/21 System Real Energy
Returns the combined energy of the system phases (see R161). The default type is Floating Point
(see R170). The default units are kWh (see R173).
Unlike Total Real Energy (above), these accumulators derive from Net Real Power (see R620). For a
3 Phase installation,
System = ∫|𝑷𝑵𝑬𝑻 | ∙ 𝑑𝑡 = ∫|𝑷𝑹 + 𝑷𝑺 + 𝑷𝑻 | ∙ 𝑑𝑡
Compare the order of the absolute value operations in this example with the Total Real Energy
derived from the Total Real Power (see R600):
Total = ∫ 𝚺𝑷 ∙ 𝑑𝑡 = ∫(|𝑷𝑹 | + |𝑷𝑺 | + |𝑷𝑻 |) ∙ 𝑑𝑡
When the individual Real Power (see R1600) of all system phases flows in the same direction
(import or export), the System accumulators track the corresponding Total accumulations exactly.
However, the System calculation allows opposite phase powers to cancel before accumulation.
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𝑃𝑅
|𝑃𝑅|
+ 𝑃𝑇
+ |𝑃𝑇|
|𝑃𝑆|
𝑃𝑆
|𝑃𝑁|
∫=7
∫=15
𝚺𝑃
Figure 11: System vs. Total Energy
The Import and Export accumulations follow the sign of Net Real Power:
|𝑷 | ∙ 𝑑𝑡
Import = � � 𝑵𝑬𝑻
0
|𝑷 | ∙ 𝑑𝑡
Export = � � 𝑵𝑬𝑻
0
𝑖𝑓 𝑷𝑵𝑬𝑻 > 0
𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
𝑖𝑓 𝑷𝑵𝑬𝑻 < 0
𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
Net Real Energy (see R706) equals any possible System Net accumulator, as the calculation does not
take absolute values.
R722/23 Import ● R724/25 Export
R740/41 Total Reactive Energy
FLOAT*
R/W/NV
FLOAT*
R/W0/NV
Returns the combined energy of the system phases (see R161). The default type is Floating Point
(see R170). The default units are kVARh (see R173). For a 3 Phase installation:
Total = R1740 + R2740 + R3740
Import = R1742 + R2742 + R3742
Export = R1744 + R2744 + R3744
R742/43 Import ● R744/45 Export
R760/61 Total Apparent Energy
Returns the combined energy of the system phases (see R161). The default type is Floating Point
(see R170). The default units are kVAh (see R173). For a 3 Phase installation:
Total = R1760 + R2760 + R3760
Import = R1762 + R2762 + R3762
Export = R1764 + R2764 + R3764
R762/63 Import ● R764/65 Export
R800/01 Demand Real Power
FLOAT
R/W0
Returns the absolute sum 𝚺𝑷𝑫 of the Demand Real Power (see R1800) of valid system phases
(as defined by R420). The default units are kW (see R163).
R802/03 Previous ● R804/05 Minimum ● R806/07 Maximum
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R820/21 Demand System Real Power
FLOAT
R/W0
FLOAT
R/W0
FLOAT
R/W0
Returns the signed sum 𝚺𝑷𝑫∙𝑵𝑬𝑻 of the Demand Real Power (see R1800) of valid system phases
(as defined by R420). The default units are kW (see R163).
R822/23 Previous ● R824/25 Minimum ● R826/27 Maximum
R840/41 Demand Reactive Power
Returns the absolute sum 𝚺𝑸𝑫 of the Demand Reactive Power (see R1840) of valid system phases
(as defined by R420). The default units are kVAR (see R163).
R842/43 Previous ● R844/45 Minimum ● R846/47 Maximum
R860/61 Demand Apparent Power
Returns the absolute sum 𝚺𝑺𝑫 of the Demand Apparent Power (see R1860) of valid system phases
(as defined by R420). The default units are kVA (see R163).
R862/63 Previous ● R864/65 Minimum ● R866/67 Maximum
R Phase Configuration
R1010-19 Phase Sensor Serial Number
Returns the unique serial number of the CVT.
ASCII
R
ASCII
R
BOOL
R
UINT16
R
With no CVT installed, returns “000000”.
R1020-29 Phase Sensor Model
Returns the full model of the CVT.
With no CVT installed, returns “NO SENSOR”.
R1102 Present
Returns “1” when the meter detects a connected CVT.
R1103 Status
Returns general CVT status:
1.
2.
3.
4.
5.
6.
7.
No Sensor
No Error
Detection Error
Communication Error
Configuration Error
Version Error
Technology Error
If a CVT returns any condition other than No Error, the phase measurements (see R1420 ff.) are set
invalid. In addition, the phase carries no weight in the system average calculations (see R420 ff.).
Previous phase statistics and energy accumulations are preserved.
Typically, errors result from an unreliable cable connection between the EM-RS485 and a CVT.
Disconnect the CVT from the meter and inspect the cable and connector for damage. If an error
persists when the CVT is reconnected, please contact technical support.
At EM-RS485 launch, all Senva CVTs are based on Rogowski Coil technology; Technology Error is
provided in anticipation of future CVT technology upgrades.
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R1104 PowerPrint Identity Status
Sets the status of the CVT’s PowerPrint identity:
1.
2.
3.
UINT16
R
No Identity
Identity Saved
Identity Error
The PowerPrint identity captures the digital identity of the installed CVT for reference. To initialize
or update the PowerPrint identity, activate PowerPrint (see R241) or write Identity Saved. To clear
any saved identity, write No Identity or disable PowerPrint.
Returns Identity Saved when the CVT identity matches the reference identity. Returns Identity Error
when it appears that the CVT has been removed or swapped with a different one. In the latter case,
PowerPrint also sets the Unexpected Sensor condition (see R1400).
Default: No Identity
R1140/41 Voltage Rating
FLOAT
R
Returns the CVT’s maximum rated RMS voltage. This always applies to the raw input voltage,
measured between the CVT voltage leads without considering the Voltage Multiplier (see R1142).
If the direct input voltage exceeds this rating, the Over Voltage condition (see R1400) will be set. In
Over Voltage conditions voltage, power, and energy measurements may have reduced accuracy.
WARNING: Exceeding the rated RMS voltage may result in hazardous operating conditions.
R1142/43 Voltage Multiplier
FLOAT
R/W/NV
Sets a multiplier to scale from raw input voltage to effective line voltage. Set equal to the ratio of
any potential transformer used to step down voltages higher than the maximum rating. For
example, set 35.0 when using a 4200:120 V potential transformer.
The RMS Voltage (see R1420) always returns the effective line voltage including the multiplier.
Power and energy measurements scale by the same factor.
Negative multipliers can correct installations where CVT voltage leads are installed backwards:
•
•
•
•
Has no effect on RMS Voltage (see R1420), which is always positive.
Reverses the direction (import/export) of Power Factor (see R1550), Real Power (see R1600), and
Reactive Power (see R1640).
Adds 180° to Current Angle (see R1540), unless the Current Multiplier (see R1152) is also
negative, in which case the signs cancel.
Adds 180° to both Phase to Phase Voltage Angles (see R1440) that include this phase, unless the
other phase Voltage Multiplier (see R2142, R3142) in the pair is also negative.
Default: 1.0
R1144/45 PowerPrint Voltage
FLOAT
R/W/NV
Sets the expected PowerPrint voltage. If set to any non-zero value, and RMS Voltage (see R1420)
differs from expected by more than the PowerPrint Voltage Tolerance (see R246), then either the
Brown Out Voltage or Surge Voltage conditions (see R1400) will be set.
Set the expected voltage by writing this value directly, or by initializing PowerPrint (see R241).
Default: 0 (undefined)
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R1146/47 PowerPrint Voltage Angle
FLOAT
R/W/NV
Sets the expected PowerPrint relative voltage angle between this phase and the “next” (as defined
for Voltage Angle, see R1440). If both phases have a non-zero PowerPrint Voltage (see R1144), and
the relative Voltage Angle differs from the expected angle by more than the Voltage Angle Tolerance
(see R248), then the Phase Drift condition (see R1400) will be set.
Set the expected angle by writing this value directly, or by initializing PowerPrint (see R241).
Default: 0 (undefined)
R1150/51 Current Rating
FLOAT
R
Returns the CVT’s rated RMS current. This always applies to the raw input current measured in the
Rogowski Coil loop without considering the Current Multiplier (see R1152). The rating applies only
at 60 Hz; ratings at other frequencies are inversely proportional (see R1520).
If the raw input current exceeds this rating, the Over Current condition (see R1400) may be set.
However, this condition reflects the technology capability of the current sensing loop, which may
be higher than rating in some cases. In Over Current conditions the current, power, and energy
measurements may have reduced accuracy.
R1152/53 Current Multiplier
FLOAT
R/W/NV
Sets a multiplier to scale from raw input current to effective line current. Set the inverse of the
number of times the conductor passes through the current sensor loop. For example, set 0.2 when
the conductor wraps 5 times.
WARNING: Never deform the Rogowski Coil! Wrapping a conductor may increase accuracy when
measuring very low currents, but may also reduce accuracy by deviating from the recommended
installation procedure (see Installation Instructions). Performance specifications not guaranteed.
The RMS Current (see R1520) always returns the effective line current including the multiplier.
Power and energy measurements scale by the same factor.
Negative multipliers can correct installations where a current transducer is installed backwards:
•
•
•
Has no effect on RMS Current (see R1420), which is always positive.
Reverses the direction (import/export) of Power Factor (see R1550), Real Power (see R1600), and
Reactive Power (see R1640).
Adds 180° to Current Angle (see R1540), unless the Voltage Multiplier (see R1142) is also
negative, in which case the signs cancel.
Default: 1.0
R1154 Current Sensor Technology
Returns the current sensor technology of the CVT:
1.
2.
3.
UINT16
R
Unknown Technology
Rogowski Coil
Current Transformer
Read only. If no CVT is installed, returns Unknown Technology.
At EM-RS485 launch, all Senva CVTs are based on Rogowski Coil technology. The combination of
the technology of all installed CVTs gives the System Current Sensor Technology (R152).
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R1161 Power Multiplier Override
BOOL
R/W
Returns the status of the phase Power Multiplier (see R1162). “0” indicates the default multiplier;
“1” indicates an override. Setting “0” resets the Power Multiplier to default.
Default: Inactive
R1162/63 Power Multiplier
FLOAT
R/W/NV
Sets a multiplier to scale from raw input power to reported power. For example, set 3.0 to infer the
other power and energy of all three phases of a balanced load while measuring just one. This way,
the reported measurements have the correct magnitude and scale without any post-calculation.
WARNING: The less balanced the phases, the more this technique reduces measurement accuracy,
especially for reactive power. However, the equipment and installation savings may be worthwhile
when the primary objective is a relative/trend type measurement.
Negative multipliers reverse the direction (import/export) of Power Factor (see R1550), Real Power
(see R1600), and Reactive Power (see R1640).
Setting this value also sets the Power Multiplier Override (R1161) to Active. To restore the default, set
the Power Multiplier Override to Inactive.
Default: 1.0
R1192/93 Statistics Reset
UINT32
R/W
Always returns 0. Write one of the following keys to reset some or all of the phase statistics. Writing
any other value results in an error response.
WARNING: Selected statistics will be permanently lost; previous records cannot be recovered.
NOTE: Each phase has different keys, which are also different from the system reset keys. This
guarantees that statistics cannot be accidentally reset by writing a key to the wrong register.
R Phase (R1192):
•
•
•
•
Write 7779749 to reset analog statistics (R1420 – R1672: Minimum, Maximum, Average)
Write 5207141 to reset demand statistics (R1800 – R1866: Minimum, Maximum)
Write 7564709 to clear accumulated energy (R1700 – R1766: All Registers)
Write 6204517 to reset all R Phase statistics
S Phase (R2192):
•
•
•
•
Write 6600105 to reset analog statistics (R2420 – R2672: Minimum, Maximum, Average)
Write 7173225 to reset demand statistics (R2800 – R2866: Minimum, Maximum)
Write 4287913 to clear accumulated energy (R2700 – R2766: All Registers)
Write 6073449 to reset all S Phase statistics
T Phase (R3192):
•
•
•
•
Write 4240817 to reset analog statistics (R3420 – R3672: Minimum, Maximum, Average)
Write 4813937 to reset demand statistics (R3800 – R3866: Minimum, Maximum)
Write 6516145 to clear accumulated energy (R3700 – R3766: All Registers)
Write 4369521 to reset all T Phase statistics
Phase statistics may also be reset by a System Statistics Reset (see R192). Analog statistics are
automatically reset whenever the meter itself resets (see R103). Individual analog and demand
statistics may also be automatically reset when Auto Reset Statistics is Active (see R195).
Resetting any subset of accumulated energy increments the Energy Reset Count (see R194).
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R Phase Measurements
R1400 Active Conditions
UINT16
Returns an encoded set of flags representing active phase conditions:
•
•
•
•
•
•
•
•
•
•
Negative Power (see R1600)
Phase Loss (see R1420)
Bad Frequency (see R1420)
Low Power Factor (see R1550)
Over Current (see R1150)
Over Voltage (see R1140)
High Harmonics (see R1520)
Unexpected Sensor (see R1104)*
Surge Voltage (see R1144)*
Brown Out Voltage (see R1144)*
BIT [2]
BIT [3]
BIT [4]
BIT [5]
BIT [6]
BIT [7]
BIT [8]
BIT [9]
BIT [11]
BIT [13]
R
4
8
16
32
64
128
256
512
2048
8192
The conditions reflect the near-real-time phase status observed over the previous 1 – 2 seconds.
The CVT Status LED also indicates the active conditions (see Installation Instructions).
If no CVT is installed, always returns “0”. To decode a set of condition flags, see Appendix B.
*Conditions only reported after activating the corresponding PowerPrint feature(s).
R1401 Previous Conditions
UINT16
R/W0
Returns an encoded set of flags representing all active and historical phase conditions. Equivalent
to Active Conditions (see R1400), except that conditions remain in the set until manually cleared.
Write “0” to clear historical flags (set in R1401 but no longer set in R1400). Flags are also cleared
when the meter resets. Active flags (still set in R1400) cannot be effectively cleared, since they will
be immediately re-set.
R1420/21 Phase RMS Voltage
FLOAT
R/W0
Returns the effective line RMS voltage 𝑽 measured between the CVT voltage leads and multiplied
by the Voltage Multiplier (see R1142), in V. Always positive, regardless of the sign of the multiplier.
When voltage exceeds the Voltage Rating (see R1140), the
measurement may have a reduced accuracy.
In Phase Loss condition, the Real Power (see R1600),
Reactive Power (see R1640), and derived measurements
become invalid. Apparent Power (see R1660) remains
valid down to 2% of the Voltage Rating (about 12 V for a
600 V rated CVT), although measurements may have a
reduced accuracy. Below 2%, returns 0 V.
Over Range
Reduced Accuracy
Voltage % of Rating
When the voltage drops below 15% of the Voltage Rating
(about 90 V for a 600 V rated CVT), the Phase Loss
condition (see R1400) may be set. Even at higher RMS
voltages, Phase Loss may still occur if the frequency
exceeds the system limits (see Installation Instructions).
Normal Operation
Full Accuracy
Under Range
Reduced Accuracy
100%
15%
2%
No Operation
0%
Figure
Voltage
Range
Figure
12:13:
Voltage
Range
With a PowerPrint Voltage target set (see R1144),
voltage variations may set the Brown Out Voltage (too low) or Surge Voltage (too high) conditions
(see R400). The default smoothed value response time is 10 seconds (see R144).
R1422/23 Instantaneous ● R1424/25 Minimum ● R1426/27 Maximum ● R1428/29 Average
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R1440/41 Phase to Phase Voltage Angle
FLOAT
R/W0
Returns the relative angle 𝜽 between the voltage of this phase and the “next” (definition below).
The default units are Degrees (see R153), normalized between –180 and +180°.
IMPORANT: Unlike most measurements (intra-phase and independent), the definition of phase to
phase voltage depends on “next” phase. The complete progression:
•
•
•
R1440
R2440
R3440
R Phase to S Phase
S Phase to T Phase
T Phase to R Phase
τ = 360°
R
Positive angles indicate that the “next” phase lags this phase
(see Figure 15). A negative Voltage Multiplier (see R1142) for
one phase rotates the result by 180°, also normalized.
(Negative multipliers on both phases cancel each other)
time
S
This measurement assumes that both phases have the same
frequency (the meter does not check). If the voltage of either
phase drops too low, this value returns 0 V.
θ
Figure 14: Phase Progression
With a PowerPrint Voltage Angle target set (see R1146), angle
variations may set the Phase Drift condition (see R400).
With no PowerPrint Voltage Angle target, the meter substitutes 120°, a standard angle for 3-phase
services. Three angles of approximately –120° will set the Reverse RST Order condition. Three
angles not approximately equal to either –120° or +120° will set the Not Three Phase condition.
Phase Loss on either phase blocks both conditions from being set.
The default smoothed value response time is 60 seconds (see R142).
R1442/43 Instantaneous ● R1444/45 Minimum ● R1446/47 Maximum ● R1448/49 Average
R1450/51 Phase to Phase RMS Voltage
FLOAT
R/W0
Returns the RMS voltage 𝑽𝑷𝑷 between the “hot” leads of this phase and the next (as defined by
R1440), in V. This calculation assumes a common neutral connection (see Figure 15) between
phases and that both phases have the same frequency (the meter does not check for either).
CVT 2
V2
θ
VPP
CVT 1
V1
Figure 15: Phase to Phase Common Neutral
The following equation represents the basic phase to phase voltage calculation:
𝑽𝑷𝑷 = �(𝑽𝟏 − 𝑽𝟐 𝐜𝐨𝐬 𝜽)𝟐 + (𝑽𝟐 𝐬𝐢𝐧 𝜽)𝟐
A negative Voltage Multiplier (see R1142) for exactly one phase rotates the result by 180°, effectively
reversing the polarity of the neutral and “hot” leads.
The default smoothed value response time is 10 seconds (see R144).
R1452/53 Instantaneous ● R1454/55 Minimum ● R1456/57 Maximum ● R1458/59 Average
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R1520/21 Phase RMS Current
FLOAT
R/W0
Returns the effective line RMS current 𝑰 measured with the CVT current sensing loop and multiplied
by the Current Multiplier (see R1152), in A. Always positive, regardless of the sign of the multiplier.
When the current exceeds the Current Rating (see R1150) the measurement may have reduced
accuracy.
Fundamentally, Rogowski coils measure changes in current, not current itself. This is why Rogowski
coils are not well-suited for DC current measurements and also why they may be sensitive to high
frequency harmonics. Even though a particular RMS current may be within the CVT Current Rating,
individual harmonic components may exceed the input range.
If the meter detects that current harmonics may lead to reduced accuracy, the High Harmonics
condition (see R1400) will be set. However, given the wide variation in harmonics between
different loads, the meter cannot detect every possible scenario leading to reduced accuracy.
The default smoothed value response time is 2 seconds (see R154).
R1522/23 Instantaneous ● R1524/25 Minimum ● R1526/27 Maximum ● R1528/29 Average
R1540/41 Phase Current Angle
FLOAT
R/W0
Returns the four quadrant current angle 𝝋. The default units are Degrees (see R153), normalized
between –180 and +180°. A negative Current Multiplier (see R1152) rotates the result by 180°,
effectively reversing the orientation of the current sensor loop.
𝝋 = −atan
𝑸
𝑷
Displacement power factor may be easily derived from
current angle:
𝒑𝒇𝑫 = cos(𝝋) =
Q
–Real
Internally, the meter calculates from the vector formed by
Real Power (see R1600) and Reactive Power (see R1640).
Note the negation required to maintain sign convention
(see Figure 17):
Export
Leading +Reactive
1
2
�1 + �𝑸�
𝑷
Import
Lagging
I
-φ V
P
Export –Reactive
Lagging
+Real
Current angle measures the angle of the phase current
fundamental with respect to the voltage fundamental.
Positive angles represent leading (capacitive) loads.
Import
Leading
Figure 16: Current Angle Quadrants
During Phase Loss conditions (see R1420), Current Angle becomes undefined because Real Power is
undefined. Outside of Phase Loss, very low real power levels with small signal-to-noise ratios can
lead to unstable results. In both cases this register returns 0°.
The default smoothed value response time is 2 seconds (see R154).
R1542/43 Instantaneous ● R1544/55 Minimum ● R1546/47 Maximum ● R1548/49 Average
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R1550/51 Phase Power Factor
FLOAT
R/W0
Returns true (a.k.a. apparent) power factor 𝒑𝒇. A negative value indicates export power.
𝒑𝒇 = 𝑷�𝑺 = 𝑷�𝑽 ∙ 𝑰
When power factor drops below 0.5 (absolute value), the Low Power Factor condition (see R1400) is
set. Low Power Factor may indicate an installation error (see Installation Instructions).
The default smoothed value response time is 2 seconds (see R154).
R1552/53 Instantaneous ● R1554/55 Minimum ● R1556/57 Maximum ● R1558/59 Average
R1600/01 Phase Real Power
FLOAT
R/W0
Returns real power 𝑷, after multiplication by the Power Multiplier (see R1162). The default units are
kW (see R163). A negative value indicates export power.
The Import and Export Averages only update during the respective intervals (see Figure 17). The
Import Average is always positive, and the Export Average is always negative. When power flows
exclusively in one direction, one of these will remain at 0 kW.
Maximum
Import Average
Overall Average
Export Average
Minimum
Figure 17: Real Power Averages
When Real Power drops very low (not always during Phase Loss), the Current Angle (see R1540) and
Power Factor (see R1550) measurements become unstable. In addition, the CVT Status LED indicates
the No Load condition (see Installation Instructions).
During Phase Loss conditions (see R1420), returns 0 kW and the Averages stop updating.
The default smoothed value response time is 2 seconds (see R164).
R1602/03 Instantaneous ● R1604/05 Minimum ● R1606/07 Maximum
R1608/09 Overall Average ● R1610/11 Import Average ● R1612/13 Export Average
R1640/41 Phase Reactive Power
FLOAT
R/W0
Returns reactive power 𝑸, after multiplication by the Power Multiplier (see R1162). The default units
are kVAR (see R163). A negative value indicates a capacitive load (leading power factor).
The Import and Export Averages only update during the respective Real Power (see R1600) intervals.
When Real Power flows exclusively in one direction, one of these will remain at 0 kW. All three
averages may be positive or negative, depending on the mix of capacitive and inductive loads.
During Phase Loss conditions (see R1420), returns 0 kVAR and the Averages stop updating.
The default smoothed value response time is 2 seconds (see R164).
R1642/43 Instantaneous ● R1644/45 Minimum ● R1646/47 Maximum
R1648/49 Overall Average ● R1650/51 Import Average ● R1652/53 Export Average
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R1660/61 Phase Apparent Power
FLOAT
R/W0
Returns apparent power 𝑺, after multiplication by the Power Multiplier (see R1162). The default
units are kVA (see R163). Apparent power is always positive:
𝑺=𝑽∙𝑰
The Import and Export Averages only update during the respective Real Power (see R1600) intervals.
When Real Power flows exclusively in one direction, one of these will remain at 0 kW.
When the RMS Voltage becomes invalid (see R1420), returns 0 kVA and the Averages stop updating.
The default smoothed value response time is 2 seconds (see R164).
R1662/63 Instantaneous ● R1664/65 Minimum ● R1666/67 Maximum
R1668/69 Overall Average ● R1670/71 Import Average ● R1672/73 Export Average
R1700/01 Total Phase Real Energy
FLOAT*
R/NV
Returns the accumulation of Real Power 𝑷 (see R1600). The default type is Floating Point (see R170).
The default units are kWh (see R173).
Note the absolute value operation in the accumulation of Total but not Net:
Total = ∫|𝑷| ∙ 𝑑𝑡
Net = ∫ 𝑷 ∙ 𝑑𝑡
∫A = 4
∫C = 2
∫B = –8
Total =
Import =
Export =
Net =
14
6
8
-2
Figure 18: Real Energy
The Import and Export accumulations follow the sign of Real Power:
|𝑷| ∙ 𝑑𝑡
Import = � �
0
|𝑷| ∙ 𝑑𝑡
Export = � �
0
𝑖𝑓 𝑷 > 0
𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
𝑖𝑓 𝑷 < 0
𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
Accumulation stops during Phase Loss conditions (see R1420).
R1702/03 Import ● R1704/05 Export ● R1706/07 Net
R1740/41 Total Phase Reactive Energy
FLOAT*
R/NV
Returns the accumulation of Reactive Power 𝑸 (see R1640). The default type is Floating Point (see
R170). The default units are kVARh (see R173).
Total = ∫|𝑸| ∙ 𝑑𝑡
The Import and Export accumulations follow the sign of Real Power 𝑷 (see R1600):
|𝑸| ∙ 𝑑𝑡
Import = � �
0
|𝑸| ∙ 𝑑𝑡
Export = � �
0
𝑖𝑓 𝑷 > 0
𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
𝑖𝑓 𝑷 < 0
𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
Accumulation stops during Phase Loss conditions (see R1420).
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154-0023-0A-DRAFT
Although Reactive Power itself is signed, the accumulators capture only the magnitude without
distinguishing between capacitive and inductive modes. Consider calculating this from average
power (one of R1648 – R1652) over an interval instead:
R1742/43 Import ● R1744/45 Export
Net = 𝑸 ∙ Δ𝑡
R1760/61 Total Phase Apparent Energy
FLOAT*
R/NV
Returns the accumulation of Apparent Power 𝑺 (see R1660). The default type is Floating Point
(see R170). The default units are kVAh (see R173).
Total = ∫ 𝑺 ∙ 𝑑𝑡 = ∫ 𝑽 ∙ 𝑰 ∙ 𝑑𝑡
The Import and Export accumulations follow the sign of Real Power 𝑷 (see R1600):
Import = � �
𝑺 ∙ 𝑑𝑡
0
𝑺 ∙ 𝑑𝑡
Export = � �
0
𝑖𝑓 𝑷 > 0
𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
𝑖𝑓 𝑷 < 0
𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
Accumulation stops when the RMS Voltage becomes invalid (see R1420).
R1762/63 Import ● R1764/65 Export
R1800/01 Demand Real Power
FLOAT
R/W0
Returns the average 𝑷𝑫 of Real Power (see R1600) over a windowed interval. The default units are
kW (see R163). Negative values indicate that export energy exceeded import energy over the
course of the demand window.
Demand power bridges a gap between peak power and total energy accumulation. Many peak
power measurements are short-lived and can be absorbed by an electrical utility with minimal side
effects. However, sustained high power usage requires a fixed capacity investment regardless of
the actual consumption (for example, transmission lines). Some utilities bill larger customers for
both total energy consumption and peak demand power, although specific rules vary.
Internally, demand windows run for a fixed interval, with each new window marking the end of the
previous window. The Window Time (see R183) sets the maximum window length, and periodic
Synchronization (see R181) can help align the start of a window with an external reference.
All of the demand power registers follow the same common window schedule.
Previous Demand
Window Average
Instantaneous Power
n=0 (meter reset)
1
2
3
4
Figure 19: Fixed Demand Windows
During each window, demand continuously tracks the flow of energy in the line. When this value
stops changing at the end of the window, it becomes Previous Demand (see Figure 19). At the
same time, the Minimum and Maximum Demand statistics update with any new record(s). Finally,
the demand tracker resets for the next window. The Demand Window Count (see R186) increments
exactly once for each demand window.
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154-0023-0A-DRAFT
Formally, demand power may be defined as measured energy divided by the measurement time:
𝑡𝑛+1
𝚫𝐄 ∫𝑡𝑛 𝑷 ∙ 𝑑𝑡
𝑷𝑫 =
=
𝑡𝑛+1 − 𝑡𝑛
𝚫𝐭
Notwithstanding previous language that describes a fixed window, the primary demand power
value returns a continuously smoothed representation of Current Demand. This value smoothly
transitions between the fixed demand levels as each window develops (see Figure 20). While not a
substitute for a true sliding window calculation, this provides a more timely view of changing
demand without waiting for the end of an interval. In Full Synchronization mode (see R181), the
behavior of Current Demand is undefined.
Instantaneous Power
Current Demand
n=0
Window Average
1
2
3
Figure 20: Current Demand Smoothing
After every reset, the meter restores the non-volatile Minimum and Maximum Demand statistics.
The Current Demand becomes available immediately, but the Previous Demand requires one full
window interval to fully initialize.
R1802/03 Previous ● R1804/05 Minimum ● R1806/07 Maximum
R1840/41 Demand Reactive Power
FLOAT
R/W0
Returns the average 𝑸𝑫 of Reactive Power (see R1640) over a windowed interval. The default units
are kVAR (see R163). Negative values indicate a primarily capacitive load (leading power factor)
over the course of the interval.
R1842/43 Previous ● R1844/45 Minimum ● R1846/47 Maximum
R1860/61 Demand Apparent Power
FLOAT
R/W0
Returns the average 𝑺𝑫 of Apparent Power (see R1660) over a windowed interval. The default units
are kVA (see R163).
R1862/63 Previous ● R1864/65 Minimum ● R1866/67 Maximum
S Phase
R2000 – 2999
S Phase holding registers parallel the R Phase, offset +1000.
As an example, read R2103 for S Phase Status
T Phase
R3000 – 3999
T Phase holding registers parallel the R Phase, offset +2000.
As an example, read R3103 for T Phase Status
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Functions
The EM-RS485 supports the following functions of the Modbus Application Protocol Specification, v1.1b3.
Examples are intended to be representative; refer to the full standard for questions or clarification.
Notes:
•
•
•
The device address 145 (0x64) is arbitrarily selected.
The examples cover RTU usage only; ASCII requires a different encoding.
Refer to the Modbus standard for the CRC calculation procedure.
Data Types
Natively, Modbus holding register functions only support the UINT16 type (2 bytes). The meter constructs
additional types from two or more consecutive registers. Client interface software must support the same
construction for proper communication:
# of Registers
UINT16
BOOL
UINT32
FLOAT
ASCII
Range (hexadecimal)
1
1
2
2
–
0 – 65535 (0xFFFF), unless otherwise noted
0–1
0 – 4294967295 (0xFFFFFFFF), unless otherwise noted
±3.402823 × 1038 (IEEE-754), unless otherwise noted
Variable length, NULL terminated
UINT32 and FLOAT data always occupies two registers (4 bytes) full network byte order (MSB first). Read and
write operations must span both registers, excepting Write Single Register (0x06). FLOAT values are treated
as any other raw sequence of 4 bytes; refer to the IEEE-754 standard to interpret FLOAT contents.
The following examples show UINT32 encodings in a Modbus PDU beginning at byte [n], register [r]:
Value
Decimal
0xAABBCCDD
0x01234567
0x00010000
2864434397
19088743
65536
[n]
[n+1]
[n+2]
[n+3]
0xAA
0x12
0x00
0xBB
0x34
0x01
0xCC
0x56
0x00
0xDD
0x78
0x00
REGISTER
[r]
[r+1]
ASCII data occupies a range of registers, with each register encoding a pair of consecutive characters. Refer
to Appendix C for ASCII character encodings. The MSB of each register encodes the first ASCII character of
the pair. ASCII values support random access read and write operations on any partial register range. The
very last character (the LSB of the last register) must always be ASCII NULL (0). The following example shows
the ASCII encoding of “TESTING” in a Modbus PDU beginning at byte [n], register [r]:
OFFSET
ASCII
HEX
REGISTER
[n]
[n+1]
[n+2]
[n+3]
[n+4]
[n+5]
[n+6]
[n+7]
T
0x54
E
0x45
S
0x53
T
0x54
I
0x49
N
0x4E
G
0x47
NULL
0x00
[r]
EM-RS485 Modbus Protocol Guide
[r+1]
[r+2]
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[r+3]
154-0023-0A-DRAFT
0x03 Read Holding Registers
Returns one or more registers in a contiguous block:
[0]
[1]
[2]
[3]
[4]
Request
Device Address
Function Code
Starting Address
Register Count
CRC
Size
1
1
2
2
2
Notes
Always 0x03
𝑨 = 0 to 65535 (0xFFFF)
𝑵 = 1 to 125 registers
Successful reads return the contents of the requested registers:
[0]
[1]
[2]
[3]
[4]
Response
Device Address
Function Code
Byte Count
Register Data
CRC
Size
1
1
1
2*𝑵
2
Notes
Always 0x03
2*𝑵
Failed reads return an exception code:
Illegal Data
Illegal Address
Server Failure
Improperly formed request or Register Count out of range.
The combination of Starting Address + Register Count exceeds 65536.
Alignment fault: UINT32 and FLOAT reads must request both registers.
This function supports reads from the complete Modbus address space (registers 0 – 65535) without error,
including undefined addresses. This facilitates combined reads spanning multiple non-adjacent registers, which
may be more efficient in some circumstances. Always discard data read from undefined addresses.
Example 1: Read the current RS485 configuration (see R122 – R128), 6 values total. However, because Baud Rate
spans two registers, the Register Count must be 7 to get all the data.
Request = 0x 64 03 00 7A 00 07 2C 24
[0] [1]
[2]
[3]
[4]
Response = 0x 64 03 0E 00 03 00 64 00 01 2C 00 00 04 00 03 00 00 34 B5
[0] [1] [2] [3a]
[3b]
[3c]
[3d]
[3e]
[3f]
[4]
[3a] RS485 Protocol
[3b] Slave Address
[3c] Baud Rate
[3d] RS485 Parity
[3e] RS485 Data Bits
[3f] RS485 Stop Bits
= 0x0003
= 0x0064
= 0x00012C00
= 0x0004
= 0x0003
= 0x0000
= 3 (Modbus RTU)
= 100
= 76800
= 4 (Even Parity),
= 3 (8 Bits),
= 0 (Auto)
Example 2: Read the Frequency statistics (see R414 – R416).
Request = 0x 64 03 01 9E 00 06 AC 2F
[0][1] [2]
[3]
[4]
Response = 0x 64 03 0C 42 6F E7 6D 42 70 48 B4 42 70 0E 56 9F E9
[0] [1] [2]
[3a]
[3b]
[3c]
[4]
[3a] Minimum Frequency = 0x426FE76D
[3b] Maximum Frequency = 0x427048B4
[3c] Average Frequency = 0x42700E56
EM-RS485 Modbus Protocol Guide
= 59.976 Hz (IEEE-754)
= 60.071 Hz (IEEE-754)
= 60.014 Hz (IEEE-754)
Page 40 of 48
154-0023-0A-DRAFT
0x06 Write Single Register
Writes a value to a single register:
[0]
[1]
[2]
[3]
[4]
Request
Device Address
Function Code
Register Address
Register Value
CRC
Size
1
1
2
2
2
Successful writes echo the original request:
[0]
[1]
[2]
[3]
[4]
Response
Device Address
Function Code
Register Address
Register Value
CRC
Size
1
1
2
2
2
Failed writes return an exception code:
Illegal Data
Illegal Address
Server Failure
Notes
Always 0x06
𝑨 = 0 to 65535 (0xFFFF)
𝑿 = 0 to 65535 (0xFFFF)
Always 0x06
𝑨
𝑿
Improperly formed request.
The requested Register Address is undefined.
Write value rejected (e.g. out of range).
For convenience, this function supports direct writes to the first register (low address) of UINT32 register pairs.
Values are of course limited to the range of UINT16, and the meter expands the value internally.
ASCII registers support arbitrary writes to any individual register within the string.
Example 1: Enable PowerPrint (see R241).
Request = Response = 0x 64 06 00 F1 00 01 10 0C
[0] [1]
[2]
[3]
[4]
Example 2: Set Demand Window Time to 1 day = 1440 minutes (see R183).
Request = Response = 0x 64 06 00 B7 05 A0 33 31
[0] [1]
[2]
[3]
[4]
Example 3: Reset Elapsed Demand Window (see R184; note UINT32 register expansion).
Request = Response = 0x 64 06 00 B8 00 00 00 1A
[0] [1]
[2]
[3]
[4]
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0x08 Diagnostics
Performs miscellaneous device management functions. The Modbus protocol specifications defines several
diagnostic sub-functions, but the meter only provides support for the following sub-functions:
0x00 | Return Query Data
Returns response bytes equal to the request (echo):
[0]
[1]
[2]
[3]
[4]
Request
Device Address
Function Code
Sub-Function Code
Request Data
CRC
Size
1
1
2
–
2
Notes
Always 0x08
Always 0x00
Any data, 250 bytes or less
Example:
Request = Response = 0x 64 08 00 00 04 D2 00 00 10 0C
[0] [1]
[2]
[3]
[4]
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154-0023-0A-DRAFT
0x10 Write Multiple Registers
Writes one or more registers in a contiguous block:
[0]
[1]
[2]
[3]
[4]
[5]
[6]
Request
Device Address
Function Code
Starting Address
Write Count
Byte Count
Write Registers
CRC
Size
1
1
2
2
1
2*𝑵
2
Notes
Size
1
1
2
2
2
Notes
Always 0x10
𝑨 = 0 to 65535 (0xFFFF)
𝑵 = 1 to 123 registers
Always 2 * 𝑵
Successful writes echo the Starting Address and Write Count:
[0]
[1]
[2]
[3]
[4]
Request
Device Address
Function Code
Starting Address
Write Count
CRC
Failed writes return an exception code:
Illegal Data
Illegal Address
Server Failure
Always 0x10
𝑨
𝑵
Improperly formed request or Register Count out of range.
The combination of Starting Address + Register Count exceeds 65536.
Write value rejected (e.g. out of range), or
Write to a read-only register, or
Write to an undefined register, or
Alignment error: writes to UINT32 and FLOAT must cover both registers.
A Server Failure exception indicates that the meter rejected a write to one or more registers. Unless exactly one
value was written, it is not possible to determine which portion of the request caused the exception. The meter
attempts to write each register in the request, regardless of failure status.
Example 1: Reset the R Phase accumulated energy (see R1192, key = 7564709 = 0x00736DA5):
Request = 0x 64 10 04 A8 00 02 04 00 73 6D A5 38 4C
[0] [1]
[2]
[3]
[4]
[5]
[6]
Response = 0x 64 10 04 A8 00 02 C8 ED
[0] [1]
[2]
[3]
[4]
Example 2: Change the location string to “Panel 311.5” (see R276):
Request = 0x 64 10 14 00 00 06 0C 50 61 6E 65 6C 20 33 31 31 2E 35 00 EF B5
[0] [1]
[2]
[3]
[4]
[5]
[6]
Response = 0x 64 10 01 14 00 06 08 06
[0] [1]
[2]
[3]
[4]
EM-RS485 Modbus Protocol Guide
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154-0023-0A-DRAFT
0x11 Report Server ID
Returns device information in ASCII string format:
Request
[0] Device Address
[1] Function Code
[2] CRC
Size
1
1
2
Notes
Always 0x11
The request always returns a valid response:
[0]
[1]
[2]
[3]
[4]
[5]
[6]
Response
Device Address
Function Code
Byte Count
Server ID
Run Indicator
Additional Data
CRC
Size
1
1
1
1
1
–
2
Notes
Always 0x11
Total length of fields 3 – 5
Always 0x01
Always 0xFF (run mode)
Varies, see below
The Additional Data field returns an ASCII string with several concatenated values:
[5a]Vendor Name
[5b] Model Name
[5c] Serial Number
[5d] Firmware Version
[5e] Location String
“Senva Sensors”
“EM-RS485”
varies
varies
varies (see R276)
Example: Read the server ID:
Request = 0x 64 11 EB 7C
[0] [1] [2]
Response = 0x 64 11 31 01 FF 53
…
…
…
[0] [1] [2] [3] [4]
[5] Additional Data
65
73
32
30
6E
20
31
20
76
45
30
50
61
4D
31
61
20
2D
34
6E
53 65
52 53
35 20
65 6C
[5]
6E
34
31
20
73
38
2E
33
6F
35
31
31
72
20
2E
31
…
…
…
2E 35 96 CB
[6]
= “Senva Sensors EM-RS485 210145 1.1.0 Panel 311.5”
EM-RS485 Modbus Protocol Guide
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154-0023-0A-DRAFT
Appendix A: Common Registers
This subset of holding registers facilitates efficient bulk transfers between a meter and a logger. Each
alternate address directly maps the value of the base address, with full read and write support.
This subset is organized in 4 planes, each with a unique offset “X”:
•
•
•
•
System
R Phase
S Phase
T Phase
𝑿 = 10000
𝑿 = 11000
𝑿 = 12000
𝑿 = 13000
To calculate the final address of a mapped value, add “X” for the desired plane to the listed address offset.
For example, the R Phase RMS Voltage maps to 11222/23 (11000+222/23). For convenience, the table lists
register equivalents for the System and R Phase planes. S and T Phase registers follow the same pattern.
Address
Description
𝑿 + 200/01
Real Power ............................................... kW* ........... FLOAT .......... R/W0 ......... R600/01 ......... R1600/01
𝑿 + 202/03
Units
Type
Access System
R Phase
Total Real Energy .................................. kWh* ......... FLOAT* ........ R/NV .......... R700/01 ......... R1700/01
𝑿 + 204/05
Reactive Power ...................................... kVAR* ....... FLOAT .......... R/W0 ......... R640/41 ......... R1640/41
𝑿 + 210/11
Total Apparent Energy ....................... kVAh* ....... FLOAT* ........ R/NV .......... R760/61 ......... R1760/61
𝑿 + 216/17
Line Frequency ..................................... Hertz ......... FLOAT .......... R/W0 ......... R410/11 ......... N/A ..........
𝑿 + 222/23
RMS Voltage............................................ Volts .......... FLOAT .......... R/W0 ......... R420/21 ......... R1420/21
𝑿 + 228/29
Power Factor........................................... W/VA ........ FLOAT .......... R/W0 ......... R550/51 ......... R1550/51
𝑿 + 206/07
Total Reactive Energy.......................... kVARh* .... FLOAT* ........ R/NV .......... R740/41 ......... R1740/41
𝑿 + 212/13
(Reserved) .................................................................................................................................................................
𝑿 + 208/09
𝑿 + 214/15
𝑿 + 218/19
𝑿 + 220/21
𝑿 + 224/25
Apparent Power .................................... kVA* .......... FLOAT .......... R/W0 ......... R660/61 ......... R1660/61
(Reserved) .................................................................................................................................................................
Phase to Phase Voltage Angle ......... Degree* ... FLOAT .......... R/W0 ......... N/A .................. R1440/41
Phase to Phase RMS Voltage ............ Volts .......... FLOAT .......... R/W0 ......... R450/51 ......... R1450/51
RMS Current ............................................ Amps ........ FLOAT .......... R/W0 ......... R520/21 ......... R1520/21
𝑿 + 226/27
Current Angle ......................................... Degree* ... FLOAT .......... R/W0 ......... R540/41 ......... R1540/41
𝑿 + 232/33
(Reserved) .................................................................................................................................................................
𝑿 + 230/31
(Reserved) .................................................................................................................................................................
𝑿 + 234/35
Import Real Energy............................... kWh* ......... FLOAT* ........ R/NV .......... R702/03 ......... R1702/03
𝑿 + 240/41
Export Reactive Energy ...................... kVARh* .... FLOAT* ........ R/NV .......... R744/45 ......... R1744/45
𝑿 + 236/37
Export Real Energy ............................... kWh* ......... FLOAT* ........ R/NV .......... R704/05 ......... R1704/05
𝑿 + 242/43
Import Apparent Energy .................... kVAh* ....... FLOAT* ........ R/NV .......... R762/63 ......... R1762/63
𝑿 + 248/49
(Reserved) .................................................................................................................................................................
𝑿 + 238/39
Import Reactive Energy ...................... kVARh* .... FLOAT* ........ R/NV .......... R742/43 ......... R1742/43
𝑿 + 244/45
Export Apparent Energy .................... kVAh* ....... FLOAT* ........ R/NV .......... R764/65 ......... R1764/65
𝑿 + 246/47
(Reserved) .................................................................................................................................................................
(continued on the next page)
EM-RS485 Modbus Protocol Guide
Page 45 of 48
154-0023-0A-DRAFT
Address
Description
Units
Type
Access System
Phase
𝑿 + 250/51
Demand Real Power ............................ kW* ........... FLOAT .......... R/W0 ......... R800/01 ......... R1800/01
𝑿 + 252/53
Demand Reactive Power ................... kVAR* ....... FLOAT .......... R/W0 ......... R840/41 ......... R1840/41
𝑿 + 258/59
(Reserved) .................................................................................................................................................................
𝑿 + 254/55
Demand Apparent Power ................. kVA* .......... FLOAT .......... R/W0 ......... R860/61 ......... R1860/61
𝑿 + 260/61
Min. Phase to Phase Voltage ............ Volts .......... FLOAT .......... R/W0 ......... R454/55 ......... R1454/55
𝑿 + 256/57
(Reserved) .................................................................................................................................................................
𝑿 + 262/63
Max. Phase to Phase Voltage ........... Volts .......... FLOAT .......... R/W0 ......... R456/57 ......... R1456/57
𝑿 + 264/65
Minimum RMS Voltage ....................... Volts .......... FLOAT .......... R/W0 ......... R424/25 ......... R1424/25
𝑿 + 270/71
(Reserved) .................................................................................................................................................................
𝑿 + 266/67
𝑿 + 268/69
Maximum RMS Voltage ...................... Volts .......... FLOAT .......... R/W0 ......... R426/27 ......... R1426/27
(Reserved) .................................................................................................................................................................
𝑿 + 272/73
Minimum Power Factor ...................... W/VA ........ FLOAT .......... R/W0 ......... R554/55 ......... R1554/55
𝑿 + 278/79
Maximum Real Power ......................... kW* ........... FLOAT .......... R/W0 ......... R606/07 ......... R1606/07
𝑿 + 274/75
𝑿 + 276/77
Maximum Power Factor ..................... W/VA ........ FLOAT .......... R/W0 ......... R556/57 ......... R1556/57
Minimum Real Power .......................... kW* ........... FLOAT .......... R/W0 ......... R604/05 ......... R1604/05
* Default factory configuration. Alternate configuration possible.
EM-RS485 Modbus Protocol Guide
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154-0023-0A-DRAFT
Appendix B: Condition Flags Decoding
Reading the condition flag registers (see R400, R1400) always returns some positive integer 𝑹
encoding a set 𝑪 of one or more conditions. Conditions are encoded in binary form, with the
interpretation of bits varying between registers. Undefined bits are reserved.
Follow this iterative procedure to find 𝑪 given any value 𝑹:
1.
2.
3.
4.
5.
6.
7.
Initialize 𝑪 = { } (the empty set)
Initialize 𝑿 = 215 = 32768
If (𝑹 < 𝑋), skip to step 6
Subtract 𝑿 from 𝑹
If the register defines condition 𝑿, add that to 𝑪. Otherwise, skip.
Divide 𝑿 by 2 (move to the next smaller bit)
If (𝑿 > 1), repeat steps 3
For example, if R1400 𝑹 = 3108, then 𝑪 = { Negative Power, Low Power Factor, Surge Voltage }:
Repetition
1.
2.
3.
4.
5.
6.
7.
8.
9.
𝑹 = 3108
𝑹 = 3108
𝑹 = 3108
𝑹 = 3108
𝑹 = 3108
𝑹 = 1060
𝑹 = 36
𝑹 = 36
𝑹 = 36
10. 𝑹 = 36
11. 𝑹 = 36
Step 3
𝑿 = 32768
TRUE
𝑿 = 2048
FALSE
TRUE
𝑿 = 512
TRUE
FALSE
𝑿 = 256
TRUE
𝑿 = 32
FALSE
𝑿 =4
FALSE
𝑿 = 128
𝑿 = 64
TRUE
15. 𝑹 = 0
𝑿 =2
TRUE
16. 𝑹 = 0
𝑹=4
𝑪 = 𝑪 ∪ { Low Power Factor }
𝑹=0
𝑪 = 𝑪 ∪ { Negative Power }
𝑹 = 36
skip { Reserved Condition }
TRUE
𝑿 = 16
14. 𝑹 = 4
𝑪 = 𝑪 ∪ { Surge Voltage }
TRUE
12. 𝑹 = 4
13. 𝑹 = 4
𝑹 = 1060
TRUE
𝑿 = 4096
𝑿 = 1024
Step 5
TRUE
𝑿 = 16384
𝑿 = 8192
Step 4
𝑿 =8
TRUE
𝑿 =1
TRUE
An uncompensated PV array may explain this particular set of conditions:
•
•
•
The Negative Power condition may indicate that real power generation exceeds consumption,
at least momentarily.
The Low Power Factor condition may indicate a large reactive power, at least when compared
to the net real power (assuming that the PV array does not generate reactive power).
The Surge Voltage condition may indicate a too-small PowerPrint Voltage Tolerance (see R246),
not accounting for the voltage boost required to return power back to the grid.
EM-RS485 Modbus Protocol Guide
Page 47 of 48
154-0023-0A-DRAFT
Appendix C: Hex Conversions
HEX
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
0x0A
0x0B
0x0C
0x0D
0x0E
0x0F
0x10
0x11
0x12
0x13
0x14
0x15
0x16
0x17
0x18
0x19
0x1A
0x1B
0x1C
0x1D
0x1E
0x1F
0x20
0x21
0x22
0x23
0x24
0x25
0x26
0x27
0x28
0x29
0x2A
0x2B
0x2C
0x2D
0x2E
0x2F
0x30
0x31
0x32
0x33
0x34
0x35
0x36
0x37
0x38
0x39
0x3A
0x3B
0x3C
0x3D
0x3E
0x3F
DEC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
ASCII
NULL
!
"
#
$
%
&
'
(
)
*
+
,
.
/
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
HEX
0x40
0x41
0x42
0x43
0x44
0x45
0x46
0x47
0x48
0x49
0x4A
0x4B
0x4C
0x4D
0x4E
0x4F
0x50
0x51
0x52
0x53
0x54
0x55
0x56
0x57
0x58
0x59
0x5A
0x5B
0x5C
0x5D
0x5E
0x5F
0x60
0x61
0x62
0x63
0x64
0x65
0x66
0x67
0x68
0x69
0x6A
0x6B
0x6C
0x6D
0x6E
0x6F
0x70
0x71
0x72
0x73
0x74
0x75
0x76
0x77
0x78
0x79
0x7A
0x7B
0x7C
0x7D
0x7E
0x7F
EM-RS485 Modbus Protocol Guide
DEC
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
ASCII
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
[
\
]
^
_
`
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
{
|
}
~
HEX
0x80
0x81
0x82
0x83
0x84
0x85
0x86
0x87
0x88
0x89
0x8A
0x8B
0x8C
0x8D
0x8E
0x8F
0x90
0x91
0x92
0x93
0x94
0x95
0x96
0x97
0x98
0x99
0x9A
0x9B
0x9C
0x9D
0x9E
0x9F
0xA0
0xA1
0xA2
0xA3
0xA4
0xA5
0xA6
0xA7
0xA8
0xA9
0xAA
0xAB
0xAC
0xAD
0xAE
0xAF
0xB0
0xB1
0xB2
0xB3
0xB4
0xB5
0xB6
0xB7
0xB8
0xB9
0xBA
0xBB
0xBC
0xBD
0xBE
0xBF
Page 48 of 48
DEC LATIN-1
128
€
129
130
‚
131
ƒ
132
„
133
…
134
†
135
‡
136
ˆ
137
‰
138
Š
139
‹
140
Œ
141
142
Ž
143
144
145
‘
146
’
147
“
148
”
149
•
150
–
151
—
152
˜
153
™
154
š
155
›
156
œ
157

158
ž
159
Ÿ
160
161
¡
162
¢
163
£
164
¤
165
¥
166
¦
167
§
168
¨
169
©
170
ª
171
«
172
¬
173
­
174
®
175
¯
176
°
177
±
178
²
179
³
180
´
181
µ
182
¶
183
·
184
¸
185
¹
186
º
187
»
188
¼
189
½
190
¾
191
¿
HEX
0xC0
0xC1
0xC2
0xC3
0xC4
0xC5
0xC6
0xC7
0xC8
0xC9
0xCA
0xCB
0xCC
0xCD
0xCE
0xCF
0xD0
0xD1
0xD2
0xD3
0xD4
0xD5
0xD6
0xD7
0xD8
0xD9
0xDA
0xDB
0xDC
0xDD
0xDE
0xDF
0xE0
0xE1
0xE2
0xE3
0xE4
0xE5
0xE6
0xE7
0xE8
0xE9
0xEA
0xEB
0xEC
0xED
0xEE
0xEF
0xF0
0xF1
0xF2
0xF3
0xF4
0xF5
0xF6
0xF7
0xF8
0xF9
0xFA
0xFB
0xFC
0xFD
0xFE
0xFF
DEC LATIN-1
192
À
193
Á
194
Â
195
Ã
196
Ä
197
Å
198
Æ
199
Ç
200
È
201
É
202
Ê
203
Ë
204
Ì
205
Í
206
Î
207
Ï
208
Ð
209
Ñ
210
Ò
211
Ó
212
Ô
213
Õ
214
Ö
215
×
216
Ø
217
Ù
218
Ú
219
Û
220
Ü
221
Ý
222
Þ
223
ß
224
à
225
á
226
â
227
ã
228
ä
229
å
230
æ
231
ç
232
è
233
é
234
ê
235
ë
236
ì
237
í
238
î
239
ï
240
ð
241
ñ
242
ò
243
ó
244
ô
245
õ
246
ö
247
÷
248
ø
249
ù
250
ú
251
û
252
ü
253
ý
254
þ
255
ÿ
154-0023-0A-DRAFT
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