PLC Cannot Connect to PC

[AVIA]

Cannot connect to plc even after all parameters of transfer setup and com port are matching. I am using serial port. Attached error window

[kaare_t]

So you are using a USB->Serial converter? Are you sure it is compatible with Mitsubishi PLC? Do you have any other converter you can try to use for testing? Which cable are you using between the converter and the PLC?

[AVIA]

Thankyou for your reply. Now I have also tested it without usb to serial convertor by directly connecting it to PC serial port but the error persists. Please help.....

[kaare_t]

What cable are you using between the computer and the PLC? Did you remember to set COM1 when using it directly on the computer? For testing purposes I would definetively use the native port on the computer since some USB converters don't work very well with PLCs...

[AVIA]

There is no Usb cable used for interface also the cable used between is a standard Mitsubishi cable 422 to serial. This is connected between PLC and PC over COM 1 at 9.6 kbps

[kaare_t]

You've used 115200 in the screenshot. Which are you using? Also; what is the exact name of the cable (what is printed on it) and what color does it have? The cable is a RS232 9 pin to a RS422 DIN8 pin correct? Or is it a directly USB->RS422 DIN8 pin?

[AVIA]

Yes it was 115200 earlier but now on both com 1 and GX developer its 9600. I dont know exact name of cable. It is red coloured cable and SC 09 is mentioned on the same The cable is a RS232 9 pin to a RS422 DIN8 pin correct - Correct

[kaare_t]

OK, that sounds correct. And the bit/parity is set to: 7E1 right? You can safely set the speed to 115200 too, FX3U supports that. Do you have any BD cards or ADP cards installed, or is it a "clean" PLC?

[AVIA]

Yes as you said the bit / parity is 7E1 Yes there is a 232-BD card installed on the PLC.

[kaare_t]

Which version of GX Developer are you using? Could you try to remove the BD card just for testing? Are you sure that the cable is functioning (the red SC09 cable has a RS232<->RS422 converter inside it which can fail in some cases, which causes the cable to be defective)?

[AVIA]

it is v8.90U now i have restarted the plc, set the com port to default and it shows communication healthy. Thanks a lot for your support. Now I am stuck with read and write data from RS 232 port to a third party RFID reader. If you have any sample program kindly send the same. AVIA

[kaare_t]

The FX Communication Manual covers NoProtocol communication using BD cards, you should check it out. It has examples for GX Developer, whit read/write instructions and program examples.

[merih1774]

Hi all, I connected to FX3U-64M with SC09 via RS232 USB-to Serial Adapter(MOXA) While I am trying to ``read from plc`` there is an error appears on the screen.It says: Cannot communicate with the PLC. Execute again after checking the connections with the PLC.

[Crossbow]

This error has been discussed on these forums many times. Make sure you are using the proper COM port address based on your USB to serial adapter. This is the most common issue. And some USB to serial adapters just don't work with PLCs. Kayspan USA-19HS always has for me. Software will be set by default to use COM1. I doubt your USB to serial adapter is configured as COM1, most appear somewhere higher than 1.

[quarter20]

I agree with Crossbow. When I installed my sc-09 cable, it was set to comm port 10 in the hardware profile of the pc. I had to go into advanced port properties and manually change it. Then also had to change in on the transfer setup page of GX Developer.