RS-485 monitoring net

[John]

Hi,

I have a RS-485 net with one T100MD888 and one E-10, The PC use the 485 converter to connect to the net. The T100 with the E 10 work very well but when I want to monitor the T100 with the autoconverter RS485/232 and I open the monitor in the Trilogi the monitor display is open just for a moment and then it close and the connection is lost, it work only if I stop the T100 by the Dipswitch 4. The net is in a Lab enviroment even though I use the bias resistor. What can you recommend me?

Thank you for your attention.

John

[support]

When the T100MD888+ communicate with the E10 the PLC is the master of the network, and when you connect the PC to the same network then you are interfering with the communication between the two PLCs. TRiLOGI also pick up messages sent between the two PLCs which is not an intended response from a slave, so TRiLOGI has to close the connection and throw an exception. This is perfectly correct behavior.

You can only monitor the T100MD888+ PLC via its RS232 port since its RS232 port is now busy working with the E10.

Alternatively, you can connect a switch to a T100MD888+ digital input, and when you turn ON the switch the T100MD888+ program will stop sending data to the E10-npn+. Then the TRiLOGI software will be able to monitor the PLC properly without facing interference.