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 1,2,3,4,6,16 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 used for both devices.
Baud: 9600
Parity: None
Stop: 1
Mode: RTU Master Mode
Physical Connection: RS-485 (2 wire connection)
Honeywell Configuration:
Shedtime: 0
Duplex: Half
Loopback: Disable
Shedmode: Last
Shed SP: To LSP
Units: Percent
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
|
350
|
0
|
0
|
0
|
0
|
0
|
0
|
|
N7:10
|
0
|
0
|
5
|
350
|
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
|
|
N7:50
|
1
|
1
|
3
|
64
|
2
|
0
|
0
|
|
N7:60
|
1
|
1
|
3
|
70
|
2
|
2
|
0
|
|
N7:70
|
1
|
1
|
3
|
120
|
2
|
4
|
0
|
|
N7:80
|
5
|
1
|
16
|
200
|
2
|
120
|
0
|
|
N7:90
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
Our test command list performs the following functions.
- N7:50 This command reads the PV in engineering units. This is a floating point value so two words are read and copied to a floating point register in the PLC.
- N7:60 This command reads the Output in engineering units. This is a floating point value so two words are read and copied to a floating point register in the PLC
- N7:70 This command reads the Working Set Point. This is a floating point value so two words are read and copied to a floating point register in the PLC.
- N7:80 This is a conditional write command to UDC 3300 Working Set Point. This command will write two words representing a floating point value.
Cable Connection:
The physical connection, which was used during testing, was as follows:
|
MCM Module
|
|
Device
|
|
TXDRXD A 9
|
-----------------------------
|
Pin 14
|
|
TXDRXD B 1
|
-----------------------------
|
Pin 15
|
|
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 adapter 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)
|
