System Setup - GE P485 Instruction Manual

APPLICATION EXAMPLE

SYSTEM SETUP

9–2
This chapter describes how to set up the P485 with MM2 relay and PQMII meter to read
and write parameters. It can also be used as a guideline to setup the P485 Modbus to
Profibus Converter for communication with any GE Multilin relays.
The PQMII and MM2 devices are serially connected (daisy-chained) through RS485. The
following data is set up for the PQMII:
• Read phase current Ia, Ib, and Ic actual values from memory locations 0240h to 0242h
• Read average current from memory location 0244h
• Read neutral current from memory location 0245h
• Read average phase voltage from memory location 0286h to 0287h
The following data is set up for the MM2:
• Read motor status from memory location 0023h
• Read switch input status from memory location 0010h
• Read motor load from memory location 0035h
• Read thermal capacity from memory location 0036h
• Read metered voltage from memory location 0040h
• The START A (command code 0x0005) and STOP (command code 0x0004) commands
using Modbus function 10h: Preset multiple registers.
The memory addresses below are taken from the PQMII and MM2 instruction manuals
available at http://www.GEmultilin.com. For the PQMII, we have:
Type Parameter
Actual values Phase current Ia
Actual values Phase current Ib
Actual values Phase current Ic
Actual values Average phase current
Actual values Neutral current
Actual values Average phase voltage (2 words)
For the MM2, we have:
Type Parameter
Actual values Motor status
Actual values Switch input status
Actual values Motor Load
Actual values Thermal Capacity
Actual values Voltage
Commands Command function code
Commands Command operation code
The write command returns data in the response that should not be visible from the
Fieldbus. Also, the write commands should only be sent if the data from the Profibus
master has changed.
If the P485 detects a timeout while talking to the devices (PQMII and/or MM2), it should try
to re-establish communications before it considers the device in subnet is missing
(Number of retries), and then try again after some time (Reconnect time).
The serial communication parameters are set to 19200 bps, with no parity, 1 stop bit, and
8 data bits. The physical interface is set to RS485.
Address Format
0x0240 F1
0x0241 F1
0x0242 F1
0x0244 F1
0x0245 F1
0x0286 F3
Address Format
0x0023 F7
0x0010 F100
0x0035 F1
0x0036 F1
0x0040 F1
0x1160 F1
0x1161 F22
P485 MODBUS TO PROFIBUS CONVERTER – USER GUIDE
Read/write
Read only
Read only
Read only
Read only
Read only
Read only
Read/write
Read only
Read only
Read only
Read only
Read only
Read/write
Read/write