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Schneider Electric LUFP7 User manual
LUFP7
A way to make Masterpact
available on Profibus
Version 1.0
08/2007
Content of the document
OBJECTIVE OF THIS DOCUMENT ................................................................................... 3
SAFETY INFORMATION ..................................................................................................... 4
UNDERSTANDING THE PROFIBUS / MODBUS GATEWAY ....................................... 5
OVERVIEW OF THE LUFP7 GATEWAY.......................................................................... 7
INSTALLATION OF THE GATEWAY ............................................................................... 9
PART NUMBERS ........................................................................................................................ 9
MODBUS .................................................................................................................................. 9
Power Supply..................................................................................................................... 10
Modbus wiring:.................................................................................................................. 10
LUFP7 Modbus connector: ............................................................................................... 11
Wire between LUFP7 and junction box: ........................................................................... 11
Junction Box ...................................................................................................................... 12
PROFIBUS ............................................................................................................................... 13
CONFIGURATION OF THE GATEWAY:........................................................................ 15
WIRING .................................................................................................................................. 15
PC COM PORT: ....................................................................................................................... 16
ABC-LUFP CONFIG TOOL ..................................................................................................... 17
DETAILED PROPERTIES OF THE CONFIG TOOL ......................................................................... 18
GENERIC CONFIGURATIONS ......................................................................................... 20
PROPOSED NODES ................................................................................................................... 21
HOW TO USE THESE NODES - EXAMPLE .................................................................................. 22
PROPOSED CONFIGURATION ................................................................................................... 23
Read only configurations................................................................................................... 23
2 Micrologic: current, voltage, energy, power measures + CCM status + Breaker status
........................................................................................................................................... 24
HOW TO USE THESE CONFIGURATIONS ................................................................................... 27
CREATE CONFIGURATION FROM SCRATCH .............................................................................. 28
LIMITATIONS OF THE GATEWAY ................................................................................ 29
ADDENDUM 1: MORE ON MODBUS PROTOCOL:...................................................... 30
ADDENDUM 2: DATA TIME-RELIABILITY CALCULATION................................... 31
2
Objective of this document
The aim of this document is to explain how to have Masterpact and
Compact NS >630A available on a Profibus network. It does not aim to replace any
user manual (neither Masterpact Communication nor LUFP7 user manuals).
This document is focused on the LUFP7 - V2 gateway, which is available on the
market since beginning 2007.
Please consider the limitations before using the LUFP7 gateway with circuit breakers.
3
Safety information
Notice
Read the device instructions carefully, and look at the equipment to become familiar
with the device before trying to install, operate, or maintain it. The following special
messages may appear throughout this documentation or on the equipment to warn of
potential hazards or call attention to information that clarifies or simplifies a
procedure.
Disclaimer
Please note:
Only qualified personnel should service electrical equipment. No responsibility is
assumed by Schneider Electric for any consequences arising out of the use of this
material or the associated User Manual. This document is not intended as an
instruction manual for untrained persons.
© 2007 Schneider Electric. All Rights Reserved.
4
Understanding the Profibus / Modbus gateway
The LUFP7 gateway allows a master located on a Profibus-DP network to enter into
a dialogue with the slaves on a Modbus RTU network. This is a generic protocol
converter operating in a way which is transparent to the user.
This gateway allows you to interface many products marketed by Schneider Electric
with a Profibus-DP network.
The LUFP7 gateway behaves both as a Profibus-DP slave on the upstream network
and as a Modbus RTU master on the downstream network.
The gateway can carry out its data exchanges (inputs and outputs of all types) with
the Modbus slaves cyclically, aperiodically or in an event-driven way. All of these
Modbus exchanges make up the gateway’s «Modbus scanner» and we use the
«ABC-LUFP Config Tool» software application to configure this scanner’s
exchanges. Every item of data exchanged in this way is made available for the
Profibus-DP master, which can gain access to it in a number of ways (cyclical,
aperiodic or event-driven exchange).
The Profibus-DP network is totally separate from the Modbus network. The frames on
a network are not directly «translated» by the gateway to generate frames on the
other network. Instead, the exchanges between the content of the gateway’s memory
and the Modbus slaves make up a system which is independent of the one which is
entrusted with managing the exchanges between this same memory and the
Profibus-DP master. The system guarantees the coherence of data exchanged within
the shared memory.
5
The following example illustrates the independent management of each of the two
networks:
6
Overview of the LUFP7 gateway
Legend:
1 Detachable power connector for the gateway ( 24V ±10%).
2 Female RJ45 connector to a PC running ABC-LUFP Config Tool configuration software.
3 Female RJ45 connector for the downstream Modbus RTU network.
4 Six diagnostic LEDs.
5 Removable cover for the coding wheels used to configure the gateway. The label describing the LEDs is stuck
onto this cover.
6 Female Profibus-DP connector.
7
The gateway uses its own memory map, in order to make the link between Modbus
and Profibus networks. The inputs data corresponds to the data coming from Modbus
that will be available on the profibus network; the Output data are the one coming
from the Profibus network and will be used on the Modbus network. The general data
are used for the gateway internal purposes.
How does the gateway works?
The gateway has its own internal configuration that creates the link between both
networks and both data space. When configuring the gateway, you create the link by
linking the functions (read and write) and the memory. E.g. I want the current on
phase 1 to be available on profibus, I have to first create the read command in the
LUFP configuration, then the response in which I will indicate where I will write the
answer (in the output data), then from profibus I can read the current by sending a
read request at the specified address.
The important point is that the configuration is fixed, so you have to create offline all
the commands and the mapping. Then to send the configuration to the gateway and
only then you can get data in the profibus network.
8
Installation of the gateway
Part numbers
Part number for purchasing
LUFP7
VW3A8306D30
CSD309 (50964)
CJB306 (50963)
VW3A8106
Description:
This is the commercial name of the gateway
from Profibus to Modbus.
This is a 3 meter RJ45 – strip cable. It can be
use from the gateway to the Modbus network
This is the SubD-9 connector to be used with
the junction box
This is the junction box to be used to link all
the Modbus slave devices
RS232 to RS485 convertor + RJ45 wiring,
used for configuration (required once only for
installation)
Modbus
Modbus and LUFP7
The LUFP7 accepts the Modbus read holding registers command (0x03), preset
single register (0x06) and preset multiple registers (0x10).
You can either use the junction box or make a daisy chaining Modbus network. The
wiring is similar to any Modbus network wiring, with 2 wires.
Masterpact
Masterpact
Masterpact
Masterpact
Masterpact
Masterpact
Masterpact
Link to other
junction box (if any)
9
Please note that the following information details the solution with junction box. The
daisy chain solution can be derived from this.
Power Supply
The LUFP7 gateway shall be externally power supplied with 24V. This 24V power
supply can be common with the BCM Modbus power supply, if the power
consumption is compatible (LUFP7 maximum cunsumption is 95mA with 24V). In any
case, this power supply shall be isolated from the circuit breaker power supply (if
any).
Modbus wiring:
Overview:
Profibus network
24V
Modbus network
RJ45 – strip wire
Junction Bloc
+ SUBD-9 connector
10
LUFP7 Modbus connector:
Wire between LUFP7 and junction box:
B (pin4)
A (pin5)
To LUFP7
B
A
To junction box
Detailed view of the SUBD-9 connector (male part):
9–A
5–B
11
Junction Box
The junction box shall be 24V power supply, either directly its 24V connector or from
one of the Modbus slave connectors.
As the gateway is the Modbus master, it has to be connected to the IN port of the
junction bloc.
The LUFP7 gateway does only provide a Modbus 2 wire network, thus all the
Modbus slaves shall be compliant with a 2 wire Modbus network. For Masterpact, the
BCM is compliant with Modbus 2 wire. If you use the junction box CJB306, then you
just have to put the switch in the “2 wire” position.
Please consider the end of line termination, as in a standard Modbus network.
If you decide to use your own wiring solution, then the Modbus BCM has to be wired
this way:
(Comm+ correspond to B and Comm- correspond to A).
12
Profibus
Wiring
Connect the SUB-D 9-point male plug on the Profibus-DP connector to the ProfibusDP plug on the LUFP7 gateway.
(1) This signal is not mandatory and may be ignored for the LUFP7 gateway.
(2) The “GND” and “+5V” pins are meant to supply the line termination if it is present in the
connector being used.
The wiring is a standard Profibus wiring and shall be done as it.
13
Profibus configuration of the LUFP7
This task is limited to configuring the gateway's Profibus address, as the
communication speed on the Profibus network (9.6 kbits/s to 12 Mbits/s) is
automatically detected by the gateway.
The two coding wheels used for configuring the gateway’s address are hidden behind
the gateway cover. To remove this cover, insert the end of a small flat screwdriver
between the top of the hood and the gateway box and pull it out.
The LUFP7 gateway is identified on the Profibus-DP bus by its
address, ranging from 1 to 99.
This address is the sum of the decimal values given by the
angular positions of the bottom coding wheel (tens) and the top
coding wheel (units).
The LUFP7 gateway has no active line termination. You must use a Profibus-DP
connector with such a termination if you place the gateway at one of the ends of a
bus segment.
Mapping:
The mapping shall be made manually with the ABC config tool with help of its subnetwork monitor function. For this you need to know the content of memory needed
by each slave and each functions. Then by removing/adding on commands, you can
figure out their address.
14
Configuration of the gateway:
ABC-Lufp config tool, which is the configuration software for the LUFP7 gateway can be
downloaded from http://www.hms.se/abc_lufp.shtml among with the Lufp7 user guide. Please
note that this software shall be installed and used in english in order to allow a suitable import
of file (for the example we provide).
Wiring
The LUFP7 gateway is configured in RS485, so if the configuration is made using a PC, a
RS232 to RS485 convertor is required (VW3A8106).
15
In case you are using a different converter, the wiring between PC and LUFP7
configuration port shall be as follow:
NOTE: The inversion of the Rx and Tx signals between the gateway and the PC is
shown on the 9-point SUB-D connectors, because beyond this junction, the RS-232
signals are replaced by the D(A) and D(B) polarizations of the RS-485 signals.
PC Com port:
There is no need to configure the PC’s COM port, as ABC-LUFP Config Tool uses a
specific setup which replaces the one for the port being used. This replacement is
temporary and is cancelled as ABC-LUFP Config Tool stops using this serial port,
that is to say when ABC-LUFP Config Tool is closed.
16
ABC-LUFP config tool
The main window in the ABC Config Tool can be divided in 4 sections as follows:
A: Pull-down Menus & Tool Bar
The second drop-down menu from the left will change depending on the current
context. The Tool Bar provides quick access to the most frequently used functions.
B: Navigation Section
This section is the main tool for selecting and altering different levels of the subnetwork configuration. Entries proceeded by a ‘+’ holds further configuration
parameters or ‘sub menus’. To gain access to these parameters,
the entry must be expanded by clicking ‘+’. There are three main levels in the
navigation window, namely Fieldbus, ABC and Sub-network. Right-clicking on entries
in this section brings out additional selections related to that particular entry.
C: Parameter Section
This section holds a list of parameters or options related to the currently selected
entry in the Navigation Section.
The parameter value may be specified either using a selection box or manually,
depending on the parameter itself.
Values can be specified in decimal form (e.g. ‘42’), or in hexadecimal format (e.g.
‘0x2A’).
D: Information Section
This section holds information related to the currently selected parameter.
Remark: the configuration can be password protected (File properties or when
configuration load), but the password can not be retrieved, so be sure to keep a copy
of it in a safe place…
17
Detailed properties of the config tool
•
Fieldbus settings: the fieldbus type is Profibus-DP, as the
gateway is between Modbus and Profibus-DP
• ABC-LUFP settings:
If you want to have the communication statistics on
the Modbus side, you have to enable the statistics
and give a location for the counter (in the Input data
side of the memory)
•
Sub-Network settings: you have to fill in the communication
parameters of your Modbus network (Speed and Parity). Please note
that 8 data bits, RS485 physical standard and 1 stop bits are
compulsory when you have Micrologic.
The sub-network shall represent the physical reality of your installation (at least what
you want to be available on profibus).
On right click on the Sub-Network, you can manage your
network, either by “sub-network Monitor”, that will display the
gateway memory in link with the created nodes and functions or
by “sub-network status” that will gives you direct information on
your network (available only when gateway is connected). It is
also possible for you to add a new Node (Modbus slave), new
broadcaster (broadcast functions) and load an existing node.
When you add a new node, you have to specify
the Modbus slave address in its settings. Then on
right click on the node name you have various
functions.
- Node monitor is used to see the gateway
memory used by this node, to start or stop this
node and to send any Modbus commands on
you network.
- Add command is used to add command
(query and response), with guided frame (prefilled data)
- Add transactions is use to add a transaction,
which is the same as a command but without
any help (user has to specify all: the size of the request, its request, all the parts of the raw
data…).
18
For each command, you need a query and a response (automatically created when
you create a new command). The query and response represents most of the
Modbus raw data (except the property data as error check start byte) (please check
the annex on Modbus if you need refreshment on this topic).
e.g. read slaves 1’s register 661:
0x01
0x03
0x0294
0x0001
0x0000
CRC
Process for configuration
- Open ABC-LUFP config software
- Create the configuration (either from scratch or with generic configuration)
)
-
Connect the PC to the gateway (wiring + software connection
-
Download configuration to the gateway
Check if the configuration is OK (sub-network monitor or node monitor)
-
Disconnect from the gateway
19
Generic configurations
We provide various configurations that can be used as example in order to
understand more about how the gateway works and how to configure it. These
configurations shall be evolved in order to suit the customer’s needs, while keeping in
mind the restrictions.
2 type of file:
Configuration file, that represent an existing network
Node file, that represent one Modbus slave (Nodes correspond to Modbus slaves)
Using ABC-LUFP config tool software you can either open a configuration file, or in
an existing configuration you can insert a node from file (insert from file).
Whatever your import choice is, you have to be sure the configuration represents the
physical network (check the address in the node and its commands…). Moreover you
have to be sure that all the nodes either created or imported are compatible within
the LUFP7 memory, as each nodes data received or sent are stored in the LUFP
memory (this can be checked using the sub-network monitor: red means collision).
We have to configure the Modbus side and its link with profibus.
If x is the register written in the Micrologic Modbus guide, x-1 has to be written in the
configuration tool.
If you want to change the name of any node, then press F2.
20
Proposed nodes
Name of the
node
Type of
Micrologic
Content
CCM - Device
status
N/A: only CCM
CCM register
661:
- connected
position
- disconnected
position
- Test position
Input Area
address
(Hexadecimal)
000 to 001
Output Area
address
N/A
BCM – CB status All
Node address: 51
002 to 003
BCM register
661
N/A
MM – Currents
Node address: 1
MM registers
1016 to 1022
N/A
MM - Measures
BCM – Control
Command
All
P and H
All
Node address:
201
MM registers
1016 to
1022(currents),
1000 to
1007(voltages),
1034 to
1045(power) and
2000 to
2027(energy)
Node address:
201
Write: 7700 to
7704
004 to 011
004 to 011 (I)
N/A
012 to 021 (U,
V)
022 to 039 (P, Q,
S)
03A to 051 (E)
200 to 209
052 to 054
Trigger 0x210
(command
execution status)
Read: 802 and
803
Node address: 1
In the proposed node, the refresh time for read is 1s. For the control command, you
have to write first the command (E038 0004 0004 0000 (or 0001) and the password),
and then change the trigger byte to anything else than the previous value or 00.
Input Area corresponds to all the data that will comes from Modbus slaves to the
gateway. Output area corresponds to all the data that comes from profibus master to
the gateway.
21
While there are various nodes or various commands in one configuration file, they
are red from up to down (in the ABC-LUFP config tool software view). This is
especially important when you want to write a command, as you have to check the
results after having written the commands.
The commands can be sent cyclically, on trigger or on data changed. It is
recommended to have the read commands sent cyclically and the write command on
action (trigger or data change). The refresh / update time can be changed (query /
update / Update time), please note that the figure written is in 10ms. In case of
modifications, you have to verify that your refresh time is not to high in order to
respect the physical limitations of Modbus networks.
It is possible to have various nodes at the same address, but it is not advisable, as
the software representation will be different from the reality.
How to use these nodes - Example
These node can be used either directly only in case you have only 1 Micrologic. In
case you have more Micrologic, you have to modify:
• The slave address (Node / Slave address); it is recommended to check the
slave address not only for the node but also for each command in order to
ensure a proper address configuration
• The data location (for profibus mapping)
• For read holding register function: in response / data / data location
• For preset multiple register function: in query / data / data location
• The trigger byte if any
It is strongly advised to create a mapping of the profibus address while making the
“translation” from generic node to specific node, as it will be necessary for you to
configure your PLC / profibus Master.
22
Proposed configuration
All the configurations have been made with parity at even and a baud rate of 19200
bps.
Read only configurations
4 Micrologic: current measures + Breaker status
Please keep in mind that each 2 Profibus register has to be concatenated in order to
correspond to 1 Modbus register.
16 bytes and 2 commands per micrologic
Profibus Mapping for Micrologic 1(BCM has slave address 1 and Measurement
module 201):
Address Detail
Circuit breaker status (from Modbus register 661):
0&1
2&3
4&5
6&7
8&9
10 & 11
12 & 13
14 & 15
Bit 0 (0x01) : OF ; Indication contacts
For Compact and Masterpact : 0= Breaker is opened, 1 = Breaker is closed
Bit 1 (0x02) : SD ; Trip indication contact
For Compact : 0 = no trip, 1 = Breaker has tripped due to electrical fault or Shunt trip
For Masterpact : always 0
Bit 2 (0x04) : SDE ; Fault trip indication contact
For Compact and Masterpact : 0 = no trip, 1 = Breaker has tripped due to electrical fault
Bit 3 (0x08) : CH ; Charged (used only with motor mechanism)
For Compact : always 0
For Masterpact : 0 = Spring discharged, 1 = Spring loaded
Bit 4 (0x10) : Reserved (internal use only)
Bit 5 (0x20) : Reserved (internal use only)
Bit 6 (0x40) : Compact / Masterpact differentiation
0 = Compact NS , 1 = Masterpact
Bit 7-15 : Reserved
Nota: A bitmap mask should be used to test the Breaker status.
If a value test is used, the following values should be used for Masterpact :
0x44 Tripped discharged not RTC
0x4C Tripped charged not RTC
0x50 OFF discharged not RTC
0x51 ON discharged not RTC
0x59 ON charged RTC
0x78 OFF charged RTC
RMS current on phase 1 (1016)
RMS current on phase 2 (1017)
RMS current on phase 3 (1018)
RMS current on Neutral (1019)
Max RMS current (1020)
Ground fault current (1021)
Earth leakage current (1022)
For all the other Micrologic, the addresses are just translated by 16 (0x10).
16 to 31
32 to 47
48 to 63
Micrologic 2 (slave address 2 & 202)
Micrologic 3 (slave address 3 & 203)
Micrologic 4 (slave address 4 & 204)
23
2 Micrologic: current, voltage, energy, power measures + CCM status + Breaker status
Profibus Mapping for Micrologic 1(BCM has slave address 1, CCM has address 51
and Measurement module 201):
Address Detail
Device status:
0&1
2&3
4&5
6&7
8&9
0A & 0B
0C & 0D
0E & 0F
10 & 11
12 & 13
14 & 15
16 & 17
18 & 19
Bit 0 (0x01) : OF ; Indication contacts
For Compact and Masterpact : 0= Breaker is opened, 1 = Breaker is closed
Bit 1 (0x02) : SD ; Trip indication contact
For Compact : 0 = no trip, 1 = Breaker has tripped due to electrical fault or Shunt trip
For Masterpact : always 0
Bit 2 (0x04) : SDE ; Fault trip indication contact
For Compact and Masterpact : 0 = no trip, 1 = Breaker has tripped due to electrical fault
Bit 3 (0x08) : CH ; Charged (used only with motor mechanism)
For Compact : always 0
For Masterpact : 0 = Spring discharged, 1 = Spring loaded
Bit 4 (0x10) : Reserved (internal use only)
Bit 5 (0x20) : Reserved (internal use only)
Bit 6 (0x40) : Compact / Masterpact differentiation
0 = Compact NS , 1 = Masterpact
Bit 7-15 : Reserved
Circuit breaker status (from Modbus register 661):
Bit 0 (0x01) : OF ; Indication contacts
For Compact and Masterpact : 0= Breaker is opened, 1 = Breaker is closed
Bit 1 (0x02) : SD ; Trip indication contact
For Compact : 0 = no trip, 1 = Breaker has tripped due to electrical fault or Shunt trip
For Masterpact : always 0
Bit 2 (0x04) : SDE ; Fault trip indication contact
For Compact and Masterpact : 0 = no trip, 1 = Breaker has tripped due to electrical fault
Bit 3 (0x08) : CH ; Charged (used only with motor mechanism)
For Compact : always 0
For Masterpact : 0 = Spring discharged, 1 = Spring loaded
Bit 4 (0x10) : Reserved (internal use only)
Bit 5 (0x20) : Reserved (internal use only)
Bit 6 (0x40) : Compact / Masterpact differentiation
0 = Compact NS , 1 = Masterpact
Bit 7-15 : Reserved
Nota: A bitmap mask should be used to test the Breaker status.
If a value test is used, the following values should be used for Masterpact :
0x44 Tripped discharged not RTC
0x4C Tripped charged not RTC
0x50 OFF discharged not RTC
0x51 ON discharged not RTC
0x59 ON charged RTC
0x78 OFF charged RTC
RMS current on phase 1 (1016)
RMS current on phase 2 (1017)
RMS current on phase 3 (1018)
RMS current on Neutral (1019)
Max RMS current (1020)
Ground fault current (1021)
Earth leakage current (1022)
rms phase-to-phase voltage V12
rms phase-to-phase voltage V23
rms phase-to-phase voltage V31
rms phase-to-neutral voltage V1N
24
1A & 1B
1C & 1D
1E & 1F
20 & 21
22 & 23
24 & 25
26 & 27
28 & 29
2A & 2B
2C & 2D
2E & 2F
30 & 31
32 & 33
34 & 35
36 & 37
38 & 39
3A & 3B
3C & 3D
3E & 3F
40 & 41
42 & 43
44 & 45
46 & 47
48 & 49
4A & 4B
4C & 4D
4E & 4F
50 & 51
52 & 53
54 & 55
00 to 55
60 to B5
rms phase-to-neutral voltage V2N
rms phase-to-neutral voltage V3N
arithmetic mean of the phase-tophase voltages 1/3 x (V12+V23+V31)
arithmetic mean of the phase-toneutral voltages 1/3 x (V1N+V2N+V3N).
active power on phase 1
active power on phase 2
active power on phase 3
Total active power
reactive power on phase 1
reactive power on phase 2
reactive power on phase 3
total reactive power
apparent power on phase 1 with 3 wattmeters
apparent power on phase 2 with 3 wattmeters
apparent power on phase 3 with 3 wattmeters
total apparent power
total active energy part1 (mod10000)
total active energy part2
total active energy part3
total active energy part4
total reactive energy part1 (mod10000)
total reactive energy part2
total reactive energy part3
total reactive energy part4
total apparent energy part1 (mod10000)
total apparent energy part2
total apparent energy part3
total apparent energy part4
Status command register Open
Status command register Close
Micrologic 1 (slave address 1, 51 & 201)
Micrologic 2 (slave address 2, 52 & 202)
The second Micrologic parameters have to be derived from the table above
(translation by 0x55)
Profibus mapping for the out area (to be written by Profibus master - control command)
Address Detail
0&1
0xE038 (57400) (command number for open or close)
2&3
P1 = 0004 (total number of parameters including P1)
4&5
P2 = 0004 (circuit-breaker manager)
6&7
P3 = 0000 for Open or P3 = 0001 for Close
8&9
P4 = Password (default value = 0000)
0A to 0F free
10
Trigger byte for Micrologic 1
11 to 1F free
20 & 21 0xE038 (57400) (command number for open or close)
25
22 & 23
24 & 25
26 & 27
28 & 29
2A to 2F
30
P1 = 0004 (total number of parameters including P1)
P2 = 0004 (circuit-breaker manager)
P3 = 0000 for Open or P3 = 0001 for Close
P4 = Password (default value = 0000)
free
Trigger byte for Micrologic 2
To send the command the various step has to be followed:
- write the command parameters (from 00 to 09)
- change the trigger byte (make it different to 0 and to the previous value)
(These both steps can be achieved through 1 Profibus commands)
26
How to use these configurations
You can use these configurations as they are, or modify them. When you make a
modification, you have to be very careful with the mapping and ensure that there is no
overlapping. This can be verified using sub-network monitor, where no red shall be displayed.
The ABC-LUFP config tool can also be used to check the Modbus value of the registers and
check that the configuration is well done and used.
LUFP7 has some Led that have to be checked for debugging and ensuring the configuration
works fine (only from protocol standpoints).
27
Create configuration from scratch
In order to avoid problems:
•
•
•
Create as many node as needed (one node is a Modbus slave)
Give the Modbus address to all nodes
Create the commands with adequate parameters
• 1 Modbus register corresponds to 4 hexadecimal digits. That is 2 Bytes
• Query and respond correspond to the Modbus raw data (see annex for
more on Modbus raw data)
If you create your own node, you have to be sure that the response is correctly
configured, even if you don’t need to have this response (this is typically the case
when you write a command). In case the response is not the expected one, then the
LUFP7 will decide to re-send the command (this could create problems for “on
trigger” or “on state of data change” commands).
LUFP7 uses register numbers, whereas the Modbus guide for Micrologic gives the
register address. Thus 1 shall be deduct from each address (e.g. 7700 command
register in Modbus guide correspond to 7699 in the LUFP7 gateway).
28
Limitations of the gateway
The gateway will create a bridge between Profibus and Modbus, as this link is hardcoded, it create some memory limitations:
- The sum of Input Data and Output Data is limited to 416 bytes max.
- Maximum slave number is 8 (this is less for Micrologic, as it is composed of
various slave).
- Maximum transactions of 100 (this is 50 Modbus commands)
- Maximum memory of 512 Bytes (244 bytes of inputs data and 244 bytes of output
data)
Moreover, as the gateway will act in the Modbus network as a master and as a slave
in the Profibus network, it is impossible to have another master in the Modbus
network.
As Modbus network will be cyclically polled, keep in mind that every Modbus
command takes time on the bus before asking for a high refresh time. In case the
refresh time is to high, the gateway could not follow it, but will act as fast as possible
(minimum stop time between transactions). As the Lufp7 cyclically polls the
Micrologic, data in its memory that will be given to the profibus master can be
different from the real-time value. This time difference mostly depends on the number
of Micrologic and the number of data requested for each (see addendum for delay
calculation).
If we the time constraints is less real are and if data we want from Micrologic are not
specific (available in the communication profile), we could link the gateway with the
communication profile located in the BCM, then we can have 8 Micrologic connected
to one single LUFP7. Do not forget that communication profile needs to be activated
before use.
You must check that the size of the Profibus-DP data corresponds to the size of the
memory used for the Modbus exchanges, because the gateway configures its
Profibus-DP exchanges on the basis of the memory used by the Modbus frames. If
the sizes do not match, the fieldbus Diag LED n°4 b links at 1 Hertz frequency, cyclic
Modbus exchanges are enabled and write-access Modbus registers are set to 0.
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Addendum 1: More on Modbus protocol:
More on Modbus (function 3 /16): read + Write
Modbus function 3 and 16 are supported by the gateway.
Function 3: read holding registers
Request
2 bits
2 bits
Slave address
Function code
(03)
4 bits
4 bits
st
Address of the 1 Total number of
register requested register required
Response
2 bits
2 bits
2 bits
Slave address Function code Number of
Content of register written
(03)
byte to follow
(1 register = 2
Bytes)
Function 16: preset multiple registers
Request:
2 bits
2 bits
4 bits
4 bits
Slave
Function Data
Number
address
code (16 address of of register
= 0x10)
the 1st
to write
register to
write
Response:
2 bits
Slave address
2 bits
Function code
(16)
4 bits
CRC
4 bits
CRC
2 bits
Number
Value to write
of data
bytes to
follow
(normally
nr of reg *
2)
4 bits
4 bits
st
Address of the 1 Number of
register
registers writen
4 bits
CRC
4 bits
CRC
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Addendum 2: data time-reliability calculation
The following figure comes from average figures and shall be used only as time reference, as
in some specific cases the delay values can be much higher.
The aim is to understand / calculate the maximum time difference between the measures that
have been red and the real/physical value.
After the LUFP7 has send a Modbus read command to Micrologic (measures or protections):
Physical
values
Micrologic
registers
Refresh time:
1second
BCM
registers
Maximum
read time:
200 ms
LUFP7
registers
Profibus
Master
registers
Maximum
read time:
50 ms
In case of a read command to the BCM like breaker status, the delay between the physical
switch value and the Modbus availability is 200ms.
In case of a read command to the BCM without any query to Micrologic, the delay is 50ms.
The LUFP7 will poll continuously on Modbus; this means that as soon as it receives the
answer from a slave it will send the next message.
In case of 4 Micrologic from which you want to read the measures and the breaker status:
The following command will be sent on the bus:
- Read current Micrologic 1 (250ms)
- Read current Micrologic 2 (250ms)
- Read current Micrologic 3 (250ms)
- Read current Micrologic 4 (250ms)
- Read status Micrologic 1 (50ms)
- Read status Micrologic 2 (50ms)
- Read status Micrologic 3 (50ms)
- Read status Micrologic 4 (50ms)
The LUFP7 will then poll the data again after 1.2 seconds. Thus the data in its
memory(available on Profibus) will be maximum 2.2 seconds “old”.
In case of 8 Micrologic from which we read data from the communication profile:
The following commands will be sent on the bus:
- Read data from Micrologic 1 (50ms)
- Read data from Micrologic 2 (50ms)
- Read data from Micrologic 3 (50ms)
- Read data from Micrologic 4 (50ms)
- Read data from Micrologic 5 (50ms)
31
- Read data from Micrologic 6 (50ms)
- Read data from Micrologic 7 (50ms)
- Read data from Micrologic 8 (50ms)
The data comes directly from the BCM, so the answer time is 50ms. The LUFP7 will be able
to poll data every 400ms.
Detailed refresh time for the communication profile:
Registers written in bold s hall be refreshed every 50 ms (events and alarms)
Registers written in bold shall be refreshed every 1.2 s (current & voltage measures)
Registers written in italic shall be refreshed every 5 s (other measures: energy…)
(Refresh here means loaded from the Micrologic to the BCM, thus the Micrologic internal
refresh time shall be added).
Let’s take the current measure example:
- 1 second Micrologic refresh
- 1.2 second BCM refresh
- 400 ms LUFP7 refresh
So the current measure data available on Profibus will be maximum 2.6 seconds “old”.
Worst case: at the gateway limitations: 8 Modbus slave + 50 commands to Micrologic:
Each commands will takes 250ms, thus the gateway will poll the same data every 250*50=
12,5 seconds
Example of the current measure:
- 1 second Micrologic refresh
- 50 ms BCM transfer
- 12.5 second LUFP7 refresh
So the current measure data available on Profibus will be maximum 13,55 seconds “old”.
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