Help me FX1S Communication via RS485

[Xuan Tien]

Hello everybody I want to control INVT CHF100A inverter (start/stop, speed ref) use RS485 from FX1N-485BD, with Mitsubishi FX1S PLC. I want to use non-protocol communication (RS/RS2 instruction) but still have no idea how to send command from PLC to inverter's control registers. Please help...

[ace21122112]

Well I got some bad news for you.... As I understand it the FX1S only uses what is called CPU protocol and can only act as a slave... I have a earler post explaining the protocol if it is of any use to you.

[Crossbow]

RS instruction can send any string of text you write in ASCII in the registers. So you need to determine what the command string looks like, write it in ASCII, and then send that ASCII with the RS instruction.

[ace21122112]

Really? Have you done this before with a fx1s? If so do you have a sample code? I have tried and tried with an rs instruction but it never does anything I run a com check program on my laptop and monitor the output of the card (in this case a fx1n-232bd) and it is as dead as a doornail.

[Crossbow]

I have used RS on FX2N, and RS2 on FX3U. I don't use FX1S, so I have not done it there. But it is a supported command, and if you set PLC parameters correctly (or set D8210 in program), it should function fine.

[ace21122112]

Can I ask what you set D8120 to? I set mine to 897 - (0000 0011 1000 0001) as I understand this is 9600,8,n,1 with header and terminator. Command line = no Protocol. No checksum The activity LED's dont do anything. I have the laptop running serial monitoring software connected with null modem cable?

[Crossbow]

I don't set D8120, I do it in PLC parameters. There is a bit by bit breakdown in the FX Communications manual JY997D16901.