Problem Solution Overview
We performed testing between the subject device and our 3100-MCM and 3150-MCM product.
Solution Brief
We performed testing between the subject device and our 3150-MCM product. Our testing generated the following results:
- We were able to successfully communicate with the device. (see below for configuration parameters used during the testing)
- The product supports Modbus function codes 3, 6 for data movement.
The purpose of our testing is to assure a level of compatibility in the communications between the two products. Through this testing, we attempt to identify problem areas that may arise when implementing the interface in the field.
Configuration:
The product testing was performed with the following settings.
Baud: 9600
Parity: None
Stop: 1
Mode: RTU Master Mode
Physical Connection: RS-485 (2 wire connection)
The Module Configuration used in our testing was as follows:
|
Address
|
0
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
|
N7:0
|
0
|
0
|
5
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
N7:10
|
0
|
0
|
5
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
N7:20
|
4
|
1
|
2
|
130
|
150
|
0
|
0
|
0
|
4
|
0
|
This configuration, in combination with the example ladder logic referenced below, generates the following memory map:
N10:0 to N10:129 - Slave Data
N10:200 to N10:249 - Write Data
N10:130 to N10:149 - Slave Error Table (Contains revision level information also)
N10:150 to N10:199 - Master Error Table (Contains status of commands for diagnostics)
Command List:
The following command list shows some of the commands which were used to test the communications:
|
Address
|
0
Port
Number
|
1
Slave
Number
|
2
Function
Code
|
3
Source
Address
|
4
Count
|
5
Dest.
Address
|
6
Read
Type
|
|
N7:50
|
1
|
1
|
3
|
0
|
1
|
0
|
0
|
|
N7:60
|
1
|
1
|
3
|
2
|
1
|
1
|
0
|
|
N7:70
|
1
|
1
|
3
|
4
|
1
|
2
|
0
|
|
N7:80
|
5
|
1
|
6
|
200
|
1
|
7
|
0
|
Our test command list performs the following functions.
- N7:50 This command reads analog output current. Value is stored at N10:0.
- N7:60 This command reads status and errors. Value is stored at N10:1
- N7:70 This command reads the unit type. Value stored at N10:2
- N7:80 This command does a conditional write to turn LED on or off.
Cable Connection:
The physical connection which was used during testing was as follows:
|
MCM Module
|
|
Device
|
|
TxRxD 9
|
-----------------------------------
|
MA
|
|
TxRxD 1
|
-----------------------------------
|
MB
|
|
RTS 7
|
----------------|
|
Jumper between RTS/CTS on module must be installed
|
|
CTS 8
|
----------------|
|
|
GND
|
|
|
For ease of installation, termination on the ProSoft module was accomplished using our screw termination adaptor for the DB-9 plug. A similar screw termination plug is also available for the DB-25 required for the 3100-MCM. The part number for these is:
1451-9F: DB-9 to RS-422/RS-485 Screw Terminals (for 3150-MCM)
1452-25M: DB-25 to RS-422/RS-485 Screw Terminals (for 3100-MCM)
|
