Power Measurement 7000 Series
Problem Solution Overview
We performed testing between the subject device and our 3100-MCM product.
Solution Brief
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 supported Modbus functions 3 & 16
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 used:
- Baud: 9600
- Parity: None
- Stop: 1
- Mode: RTU Master Mode
- Physical Connection : RS-485
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
|
2
|
0
|
0
|
0
|
0
|
0
|
|
N7:10
|
1
|
1
|
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
N10:130 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
|
7
Polling
Time
Preset
|
|
N7:50
|
1
|
1
|
3
|
4390
|
2
|
0
|
0
|
0
|
|
N7:60
|
1
|
1
|
3
|
5999
|
4
|
5
|
0
|
0
|
|
N7:70
|
1
|
1
|
16
|
200
|
1
|
1999
|
0
|
0
|
|
N7:80
|
1
|
1
|
16
|
201
|
4
|
5999
|
0
|
0
|
|
|
|
N7:100
|
1
|
5
|
3
|
4391
|
2
|
29
|
0
|
0
|
|
N7:110
|
1
|
5
|
3
|
5999
|
4
|
25
|
0
|
0
|
|
N7:120
|
1
|
5
|
16
|
202
|
1
|
1999
|
0
|
0
|
|
N7:130
|
1
|
5
|
16
|
203
|
4
|
5999
|
0
|
0
|
Our test command list perfoms the following functions.
7700 ION Commands
- N7:50 Read registers 4391 & 4392
- N7:60 Read registers 6000 - 6003
- N7:70 Write to access protection register 2000
- N7:80 Write to registers 6000
7300 ION Commands
- N7:100 Read registers 4391 & 4392
- N7:110 Read registers 6000 - 6003.
- N7:120 Write to access protection register 2000
- N7:130 Write to registers 6000
Cable Connection:
The physical connection which was used during testing was as follows:
|
3100-MCM
Module
|
|
7300 ION
|
|
14 TxRxD+
|
----------------------
|
+ Terminal
|
|
25 TxRxD-
|
----------------------
|
- Terminal
|
|
4 RTS
|
------------|
|
|
|
5 CTS
|
------------|
|
|
|
3100-MCM
Module
|
|
7700 ION
|
|
14 TxRxD+
|
-------------------
|
+ Terminal
|
|
25 TxRxD-
|
-------------------
|
- Terminal
|
|
4 RTS
|
---------|
|
|
|
5 CTS
|
---------|
|
|
Additional Comments and Observations:
- On both the 7300 and the 7700 ION units a write to the access protection register must immediately precede a write of any kind. This may apparently be of any value and is a change from the 3000 series where the value must be the password for the unit.
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