OMNI 3000 Flow Computer
Problem Solution Overview
We performed testing between the subject device and our 3150-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 supports Modbus function codes 1, 3, 5, 6, 15, 16 for data movement. In addition, the OMNI 3000 Flow Computer supports several function codes ( 65, 66) which the MCM does not support. These additional codes are not required for a successful connection.
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-232 (3 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
|
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
N10:200 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
|
7101
|
1
|
0
|
0
|
|
N7:60
|
5
|
1
|
5
|
3200
|
1
|
1732
|
0
|
|
N7:70
|
1
|
1
|
1
|
1105
|
10
|
160
|
0
|
|
N7:80
|
5
|
1
|
16
|
210
|
1
|
4837
|
0
|
|
N7:90
|
1
|
1
|
3
|
4837
|
1
|
30
|
0
|
Our test command list performs the following functions.
- N7:50 This command reads Gross Flow-Rate for Meter run 1. Value is stored at N10:0.
- N7:60 This is a conditional command to set the Acknowledge bit for Meter run 1 Alarm.
- N7:70 This command reads the Active Flag for Meter run 1.
- N7:80 This command does a conditional write of the Company Name from N10:210.
- N7:90 This command reads the Company Name from the OMNI 3000 and places it in N10:30.
Cable Connection:
The physical connection which was used during testing was as follows:
|
MCM
Module
|
|
Device
|
|
TXD 2
|
-----------------------
|
7 RXD
|
|
RXD 3
|
-----------------------
|
9 TXD
|
|
GND 5
|
-----------------------
|
10 GND
|
|
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)
|
