GE P485 instruction manual For the MM2, we have, Type Parameter Address Format Read/write

APPLICATION EXAMPLE

SYSTEM SETUP 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	Address	Format	Read/write
Actual values	Phase current Ia	0x0240	F1	Read only
Actual values	Phase current Ib	0x0241	F1	Read only
Actual values	Phase current Ic	0x0242	F1	Read only
Actual values	Average phase current	0x0244	F1	Read only
Actual values	Neutral current	0x0245	F1	Read only
Actual values	Average phase voltage (2 words)	0x0286	F3	Read only
For the MM2, we have:

Type	Parameter	Address	Format	Read/write
Actual values	Motor status	0x0023	F7	Read only
Actual values	Switch input status	0x0010	F100	Read only
Actual values	Motor Load	0x0035	F1	Read only
Actual values	Thermal Capacity	0x0036	F1	Read only
Actual values	Voltage	0x0040	F1	Read only
Commands	Command function code	0x1160	F1	Read/write
Commands	Command operation code	0x1161	F22	Read/write

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.

9–2 P485 MODBUS TO PROFIBUS CONVERTER – USER GUIDE