FX Communication

[desuhardi]

Hello, I want to control ABB ACS550 inverter (start/stop, speed ref) use RS485 from FX1N-485BD, with Mitsubishi FX1N PLC. I've both manual of them but still have no idea how to send command from PLC to inverter's control registers. Please help...

[kaare_t]

What protocol do the inverter use? What programming software do you use? Do you have the possibility to post up the manual for the inverter?

[desuhardi]

Hi Karee, This is communication manual of inverter. Protocol is standard modbus, via RS485.\ I'm using GX Developer for programming FX PLC. ACS550 Fieldbus.pdf

[kaare_t]

There's no built in functionality for the Modbus protocol in the FX1N. You should consider changing the PLC to a FX3G to be able to use the built in functions of the ADP cards. If you really want, and have the knowledge you can program the protocol yourself using ladder in GX Developer. You could also consider going to GX Works 2 and use freely available function blocks to implement the Modbus protocol in a FX1N.

[desuhardi]

Hi Karee, Do you mean I can use FX1N PLC with FX1N-485BD for modbus protocol, use GX Developer (ladder) or GX Works 2 ?

[kaare_t]

You can program the Modbus protocol yourself using ladder code, but this is not a trivial task. Let me know if you want to program the protocol yourself, I can point you to the correct Modbus protocol specifications. Another alternative is to use GX Works 2. They have made some functionblocks that you can import into your GX Works 2 project, and you can simply link the function block to your desired devices. Check out this link: http://www.beijer.no...12578A100423B88

[Crossbow]

You would need to form a Modbus packet and use the RS instruction to send it. There is no built in command for Modbus in the FX1N.

[desuhardi]

Any documents that explain how to make form of Modbus package or sample of programs ? Thank you

[kaare_t]

Check out www.modbus.org. Here's a driect link to the specifications: http://www.modbus.org/specs.php