I have mananged to connect to a Quantum PLC via Modbus using Modsoft on a Windows XP laptop.

Whenever I try to view the status online I get the following error:

984 - Not logged in or a user is logged in on another port. Modbus Error Code 169

What does this error mean and how can I avoid it in the future?

Many thanks.

Damon

 

Problem solved, turned out to be a faulty programming lead.

Thanks.

Damon

 

I have the same problem but with a PLC Modicon Compact 984. Please Tell me how did you solve that problem.

Thank you

 

I have that problem too.
Any suggestions?

 

> I have the same problem but with a PLC
> Modicon Compact 984. Please Tell me how
> did you solve that problem.

The problem was solved with the correct cable connection:<pre>
PC DB9H PLC DB9M
nc 1 1 shield, connect to to 5 also
Rx 2----------3 Tx
Tx 3----------2 Rx
DTR 4----------6 DSR
GND 5----------5 GND
DSR 6----------4 DTR
RTS 7-| |-7 RTS(in both sides connect 7 & 8)
CTS 8-| |-8 CTS
-- 9 9 nc</pre>