Momentum | Modbus Plus 170 PNT Series | 170 PNT Series Modbus Plus Communication Adapters for TSX

170 PNT Series
Modbus Plus Communication Adapters
for TSX Momentum
User Guide
870 USE 103 00
XXXXXX.00
11/97
Breite: 185 mm
Höhe: 230 mm
Breite: 178 mm
Höhe: 216 mm
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ã 1997 Schneider Automation Incorporated. All rights reserved.
Contents
Contents
1.1
1.1.1
1.1.2
1.1.3
1.1.4
1.1.5
1.2
1.3
1.3.1
1.3.2
2.1
2.1.1
2.1.2
2.2
2.2.1
2.2.2
2.2.3
2.3
2.3.1
2.3.2
2.3.3
870 USE 103 00
Breite: 178 mm
Höhe: 216 mm
TSX Momentum
Modbus Plus Communication
Adapters
170 PNT 110 20, 170 PNT 160 20 . . . . . . . . . . . . . . . . . . . . . . .
1
Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Network Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Voltages and Error Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Environmental Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Network Communication Status Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting the Modbus Plus Node Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How Addresses are Assigned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting the Adapter’s Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
2
2
2
2
2
3
4
4
5
Communicating
.......................
7
Using Modbus Plus for Distributed I/O Servicing . . . . . . . . . . . . . . . . . . . . . . . .
Multi-Purpose Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Distributed I/O Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How Communication Adapters Handle Messages . . . . . . . . . . . . . . . . . . . . . . .
How Messages are Defined in the Application . . . . . . . . . . . . . . . . . . . . . . . . . .
How Messages are Transacted on the Network . . . . . . . . . . . . . . . . . . . . . . . .
Mapping Data to I/O Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communication Access Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
8
8
10
10
10
11
12
13
13
14
W ith the Adapter
i
TSX Momentum
Modbus Plus
Communication
Adapters
170 PNT 110 20
170 PNT 160 20
1
These Communication Adapters can be connected to any TSX Momentum I/O
base to create a functional I/O module. They provide direct connection to the
Modbus Plus network, enabling a programmable controller to communicate with
field devices wired to the I/O base terminals. Data bits are transferred in the IEC
format.
Model 170 PNT 110 20 provides one Modbus Plus port for single-cable networks.
Model 170 PNT 160 20 has two ports for single-cable or dual-cable networks.
Figure 1 shows the layout of a typical adapter and I/O base.
Figure
1
Communication
Adapter
Side
V iew
Communication
Adapter
with TSX Momentum
Front
V iew
I/O Base
I/O Base
Modbus Plus Port B
(170 PNT 160 20 only)
Modbus Plus Port A
(both models)
Communication
Adapter
I/O Base
This chapter describes:
H
Product Overview
H
Network Communication Status Indicators
H
Setting the Modbus Plus Node Address
1
Modbus Plus Communication Adapters
1.1
Product
1.1.1
Function
Overview
These adapters are installed on any TSX Momentum I/O base to form a complete
I/O module that communicates on a Modbus Plus network. A programmable
controller on the network can then read from the input terminals and write to the
output terminals of the I/O base using Modbus Plus Peer Cop or MSTR Function
Block messaging. Data bits are transmitted and received in the IEC format.
For information about the application and field wiring of I/O bases, refer to the TSX
I/O Bases User Manual , part number 870 USE 002 00.
Momentum
1.1.2
Physical
Structure
Each adapter connects to the internal communication connector of its I/O base.
Clips lock the adapter in place. The clips can be released with a common
screwdriver to remove the adapter.
Front panel labels are supplied with each I/O base. The user can fill out the label
to identify the field wiring connections and application of the I/O base terminals.
The label can then be affixed to the front panel of the adapter.
1.1.3
Network
Compatibility
Model 170 PNT 110 20 has one Modbus Plus port for connection to a network with
a single trunk cable. Model 170 PNT 160 20 has two ports for connection to either
a single-cable or dual-cable network.
Network port connections are compatible with standard Modbus Plus drop cables.
Drop cables are available from Schneider Automation in three standard lengths:
2.4 m (8 ft), 3 m (10 ft), and 6 m (20 ft).
1.1.4
Operating
Voltages
and Error Control
The adapter receives its operating voltage from the I/O base through its internal
connection to the base. The adapter monitors its voltage and goes offline to the
Modbus Plus network if the voltage is not within tolerance.
1.1.5
Environmental
Specification
The adapter conforms to the environmental specification for the I/O base upon
which it is mounted. For futher information refer to the TSX Momentum I/O Bases
User Manual , part number 870 USE 002 00.
2
Modbus Plus Communication Adapters
1.2
Network
Communication
Status Indicators
Each model has a front panel indicator showing its network communication status.
The dual-cable model has two additional indicators which identify communication
errors on the two cable paths.
Figure
2
Communication
Status
Indicators
Modbus Plus
Communication Active
(Green)
(All models)
MB+
ACT
ERROR
A
Communication Error
Channel A
(Red)
(170 PNT 160 20 only)
B
Communication Error
Channel B
(Red)
(170 PNT 160 20 only)
Table
1
Indicator
Modbus
Pattern
Plus Active Indicator
(Green)
Status
Six flashes/second
One flash/second
Two flashes, then OFF for 2 seconds
Three flashes, then OFF for 1.7 seconds
Four flashes, then OFF for 1.4 seconds
Table
2
Indicator
Modbus
(Red)
Channel A Error
Channel B Error
Plus Channel
Patterns
Normal operating state. All nodes on a
healthy network flash this pattern.
The node is off-line. After being in this state
for 5 seconds, the node attempts to go to its
normal operating state.
The node detects the network token being
passed among other nodes, but it never
receives the token.
The node does not detect any token passing
on the network.
The node has detected another node using
the same address.
Error Indicators
(170 PNT 160 20 only)
Status
Communications error at network port A.
Communications error at network port B.
3
Modbus Plus Communication Adapters
1.3
Setting
the Modbus
1.3.1
How Addresses
Plus Node Address
are Assigned
Modbus Plus nodes are identified by addresses assigned to them by the user.
Each node must have a unique address in the range 1 ... 64. Duplicate addresses
are not allowed.
Starting at address 1, the lowest addresses should be assigned to programmable
controllers. Communication adapters should be assigned the next addresses in
direct sequence. Addresses are assigned logically and are not dependent upon
the physical locations of the node devices.
Figure 3 shows typical address assignments for a network with one controller and
four communication adapters.
Figure
3
Example
of Node Address
Node 1
Assignment
Programmable Controller
with Modbus Plus Port
(Assigned Node Address 1)
Node 3
4
Node 5
Modbus Plus
Communication
Adapters
with
I/O Bases
Node 4
Node 2
Modbus Plus Communication Adapters
1.3.2
Setting
the Adapter ’s Address
The communication adapter’s address is assigned in two locations: in rotary
switches on the adapter’s front panel, and in the Peer Cop table and MSTR
function blocks of the user’s application program.
The address in the adapter’s front panel switches must correspond to the address
defined for that adapter in the application program. This is required to ensure that
messages will be sent and received properly at the intended nodes across the
network.
Figure
4
Setting
the Modbus
Plus Node Address
Do not install any adapter unless you have set
its Modbus Plus address for your application.
MB+
ACT
ERROR
A
B
X10
X1
X10
See your network
administrator to get
the node address for X1
each adapter.
Node
Upper
Lower
Address
Switch
Switch
1 ... 9
10 ... 19
20 ... 29
30 ... 39
40 ... 49
50 ... 59
60 ... 64
0
1
2
3
4
5
6
1 ... 9
0 ... 9
0 ... 9
0 ... 9
0 ... 9
0 ... 9
0 ... 4
This example sets the address to 31.
5
Communicating
W ith the Adapter
H
Using Modbus Plus for Distributed I/O Servicing
H
How Communication Adapters Handle Messages
H
Communication Access Registers
2
7
Communicating With the Adapter
2.1
Using Modbus
Plus for Distributed
I/O Servicing
Modbus Plus networks can be used to service multi purpose control applications,
or they can be organized for the most efficient servicing of distributed I/O devices.
Both approaches are outlined below.
2.1.1
Multi Purpose
Applications
Modbus Plus networks can be used for applications in which programmable
controllers, operator interfaces, and other kinds of devices must communicate.
Message timing is determined by the amount of time each node holds its token.
Timing can vary according to the current processing requirements of each node’s
internal program. For that reason, multi-purpose networks are not recommended
for servicing I/O control applications in which I/O timing must be deterministic.
In general applications, up to five networks can be joined by Bridge Plus devices
to extend the cable length to 2250 m (7500 ft) and the node count to 320 nodes.
2.1.2
Distributed
I/O Applications
Modbus Plus networks can be designed to efficiently service I/O field devices.
In such applications the timing of message transactions must be predictable to
allow deterministic timing of the I/O control process. To ensure this, the network
should consist of just one programmable controller node and the required group of
I/O nodes. Non-I/O devices, such as additional controllers, programmers, or
operator interfaces, should communicate with the I/O network controller through a
separate Modbus Plus network or other type of connection.
In distributed I/O applications, messages are transacted on the local network only.
Bridge Plus devices are not applicable to networks used for distributed I/O.
Table 3 summarizes the Modbus Plus network’s maximum configuration for a
distributed I/O application consisting of Momentum products.
8
Communicating With the Adapter
Table
3
Maximum
Distributed
I/O Configuration
(Momentum
Nodes Only)
Parameter
Specification
max. number of nodes
max. distance between two nodes
min. distance between two nodes
max. length of network
max. number of data words (16-bit words)
max. number of I/O points (16 bits/word)
64 including Controller
450 m (1500 ft)
3 m (10 ft)
450 m (1500 ft)
500 input, 500 output
8000 input, 8000 output
Figure 5 illustrates Modbus Plus network layouts using communication adapters in
a distributed I/O control application. Note that only one programmable controller
and the required I/O nodes are present in this kind of application.
9
Communicating With the Adapter
Figure
5
Communication
Node 1
Adapters
on a Distributed
I/O Network
Programmable
Controller
with
Modbus Plus
Port
Single Cable
Example
Network Trunk Cable
Tap
Drop Cable
Node 3
Node 5
Node 4
Node 2
170 PNT 110 20
with
I/O bases
I/O field device wiring
Dual Cable
Example
Network Trunk Cable A
Network Trunk Cable B
Node 1
10
Programmable
Controller
with
Modbus Plus
Redundant
Network
Option Adapter
Node 2
170 PNT 160 20
with
I/O bases
Node 3
Communicating With the Adapter
2.2
How Communication
Adapters
2.2.1
How Messages
in the Application
are Defined
Handle
Messages
The user defines I/O message transactions in the Peer Cop table of the controller.
Entries to the table are made using panel software, such as Schneider’s Concept
or Modsoft software.
The Peer Cop table specifies the controller registers that are to be used for the I/O
data storage. It also specifies the Communication Adapter node addresses which
will handle that data.
In addition to the use of Peer Cop, I/O data messages can be transacted using
Modbus Plus MSTR function blocks in the controller’s application program.
The user sets each Communication Adapter’s node address in switches on the
adapter’s front panel. The switch setting must match the address defined for that
adapter in the controller’s Peer Cop table. It must also match the address in
MSTR function blocks intended for that adapter.
2.2.2
How Messages
How Nodes Access
are Transacted
on the Network
the Network
Modbus Plus nodes access the network for transmission by acquiring a token
frame that is passed from node to node in a rotating address sequence. The node
currently holding the token has the sole right to transmit. All other nodes monitor
the network and extract messages addressed to them.
Incoming
Messages
from Communication
Adapters
When a Communication Adapter at an Input base module acquires the token, it
transmits its message to the programmable controller node. The message data
describes the current states of the signals at the base’s field input terminals.
The controller reads the message and steers its contents into the data registers
defined for that adapter’s address in the controller’s Peer Cop table.
Outgoing
Messages
to Communication
Adapters
When the programmable controller acquires the token, it transmits its messages to
the Communication Adapters. Messages are sent to the node addresses defined
in the controller’s Peer Cop table, with the message contents taken from the data
registers defined in the table.
11
Communicating With the Adapter
Each Communication Adapter at an Output base module uses its received
message to control the field devices connected to the base’s output terminals.
2.2.3
Mapping
Data to I/O Bases
Mapping of data between the controller’s data registers and the field terminals of
I/O bases is unique to each model of I/O base. Mapping is described in the TSX
Momentum I/O Bases User Manual, part number 870 USE 002 00.
12
Communicating With the Adapter
2.3
Communication
Access
Registers
Each adapter contains three groups of internal registers that enable the application
program to communicate with the I/O base module. The application can access
the registers through the network to transfer input or output data at the module’s
field terminals, to set or retrieve the module’s configuration, or to monitor its status.
The registers are accessed as 4XXXX references in a controller’s application
program. Note that the Data Registers are the only ones that can be accessed by
the controller’s Peer Cop table. All of the registers can be accessed by MSTR
function blocks.
Figure
6
Communication
Adapter
Access
Registers
MODBUS
PLUS
NETWORK
STARTING
REFERENCE
(Hex / Decimal)
LENGTH
(16-Bit Words)
DATA REGISTERS
DATA INPUT
(Read Only)
40001 / 400001
Module
dependent
DATA OUTPUT
(Write Only)
40001 / 400001
Module
dependent
MODULE TIMEOUT
(Read or Write)
4F001 / 461441
1
MODULE OWNERSHIP
(Read or Write)
4F401 / 462465
3
MODULE STATUS
(Read Only)
4F801 / 463489
12
MODULE ASCII HEADER
(Read Only)
4FC01 / 464513
1 ... 32
CONFIGURATION REGISTERS
STATUS REGISTERS
13
Communicating With the Adapter
2.3.1
Data Registers
40001 hex
Data Input or Output
Starting reference 40001 is used to address input data from field inputs and output
data to field outputs. The data field length is determined by the specific I/O base.
This reference is the only one that is accessible through Peer Cop data transfers.
All other registers can be accessed using MSTR blocks.
2.3.2
Configuration
4F001 hex
Registers
Outputs
Holdup
T imeout
Value
Reference 4F001 specifies the amount of time that outputs will be held in their
current state, if they are not updated by a new Modbus Plus Write command.
If the module’s holdup time expires before a new write command is received, all
outputs are set to logical 0 (zero).
The field length is one word. The timeout value is expressed in units of 10
milliseconds, with a minimum register value of 30 (300 milliseconds) and
maximum value of 6000 (60 seconds). The default value is 100 (1 second).
The register’s contents can be read using a Modbus Plus Read command.
4F401 hex
Ownership
of W rite Privilege
Starting reference 4F401 specifies the addresses of up to three nodes which may
concurrently own write privilege to the adapter. The field length is three words.
When the adapter first receives power, it will give sole write privilege to the first
node that writes to it. The adapter maintains an internal 60-second timer for
handling the write privilege, and will reserve sole privilege to that node as long at
the node continues to write within 60-second intervals to the adapter.
A node which currently owns the write privilege may write up to three words to the
adapter starting at reference 4F401. Each of the three words must correspond to
a valid node address in the range 1 ... 64 decimal. With those addresses stored in
the adapter, any of those three nodes may then write to the adapter. This allows
up to three nodes to concurrently own write privilege to the adapter.
If writes continue to occur within the 60 second interval from any of the three
privileged nodes, no other node may write to the adapter. If the timer is allowed to
expire, any node may write to the adapter.
Note that this 60-second Write Privilege timer is separate from the Outputs Holdup
timer, and applies only to the write privilege. Any node may read the input data or
status information from the adapter. The 60-second time is a fixed value and is
not accessible to the application.
14
Communicating With the Adapter
2.3.3
Status Registers
4F801 hex
Module
Status Block
These registers provide information about the module’s revision level and current
operating parameters.
The block’s length is 12 words. The registers can be read, but cannot be written
into.
Table
4
Reference
Module
(hex)
Status Block Layout
Purpose
Contents
4F801
4F802
4F803
4F804
4F805
Length of status block (words)
I/O module quantity of input bytes
I/O module quantiy of output bytes
I/O module ID number
I/O module revision number
4F806
4F807
4F808
ASCII header block length (words)
Last node address to communicate
Remaining ownership reservation time
4F809
Remaining outputs holdup time
4F80A
I/O module health
4F80B
4F80B
I/O module last error value
I/O module error counter
12 decimal
Module dependent
Module dependent
Module dependent
Format: XR
where:
X = upper 4 bits, always 0000
R = lower 12 bits, defining the
revision as 3 hex characters.
Example:
100 hex = Rev. 1..00
200 hex = Rev. 2.00
Module dependent
1 ... 64 decimal
30 ... 6000 decimal, in units of
10 ms (300 ms ... 60 s)
30 ... 6000 decimal, in units of
10 ms (300 ms ... 60 s)
8000 hex = healthy
0000 hex = not healthy
Module dependent
Error count 0000 ... FFFF hex
4FC01 hex
Module
ASCII Header
Block
These registers contain an ASCII text description of the module. The registers
can be read, but cannot be written into.
The block length depends upon the type of I/O base to which the adapter is
connected. The maximum length is 64 bytes of ASCII characters, corresponding
to a length of 8 ... 32 words as specified in word 6 of the module status block (at
reference 4F806).
The following table shows the header block layout as a string of ASCII characters
as they are positioned from the starting reference 4FC01.
15
Communicating With the Adapter
Table
5
Module
ASCII Header
Block Layout
4FC01 +
Byte Offset
ASCII
Characters
0 ... 10
11
12
13 14 15
16
17 18 19
20 21
MODBUS PLUS
20 hex (32 decimal)
20 hex (32 decimal)
I E C
20 hex (32 decimal)
D I G
E X P
A N A
HHLL
22 23
IIOO
Meaning
Modbus Plus network device
space
space
IEC data mode (Data bit order per IEC standard)
space
Digital module (ID range: XX00 ... XX7F hex)
Expert module (ID range: XX80 ... XXBF hex)
Analog module (ID range: XXC0 ... XXFE hex)
Module ID code
(HH = high byte, LL = low byte)
Module I/O words
(II = input words, OO = output words)
Reserved
24 ... 63
Figure
7
Examples:
ASCII Header
170 ADM 350 00 (Discrete
Block
16 Point
Input, 16 Point
Output
Module)
MODBUS PLUS IEC DIG 0002 0101
Data bits transferred
in IEC format
Input words: 1
Output words: 1
Digital
module
170 AAO 120 00 (Analog
Module ID
4 Channel
Output
Module)
MODBUS PLUS IEC ANA 01C3 0005
Data bits transferred
in IEC format
Analog
module
16
Input words: 0
Output words: 5
(includes 1
parameter word)
Module ID
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