Output and com port

[krolikbest]

Hi,

 i'm new on this forum so i'd like to say welcome at first. And second ask about some odd issue:

hardware spec : V700+ v200-18-e2b. Having startup display and two additional displays. one for automatic mode and one for manual mode. Every mode has own subroutine. In start-up display one can choose which mode. The PLC controller in automatic mode connects with servo and sends datas via modbus (that works). In manual mode there is simply (as a subroutine):

--/ /--()-

if button pressed (let's say MB 113) then  open (O 0)

 

For a connection I use com1  as a RS232. Watching this online I see I press the button (MB113  makes active-red color) but output remains still off. I started searching what is going on and checked that this happens when com1 is connected to servo but usb cable I use to programm is disconnected from the PC computer.

On the other hand when i disconnect com1 from PLCside or servo side then pressing button (MB113) makes output O0 active. If I connect usb cable to PLC and having connected com1 to plc and servo it works as well. Odd, at least for me. In main routine there is no modbus blocks, but at start-up com init and modbus config.  What can cause this problem?

[krolikbest]

OK i'm almost sure that this issue causes rs232 cable. so please set it as solved.

[Joe Tauser]

If you're connecting via USB then the PLCs COM 1 serial port will be disconnected by design.  The PLC has a built-in USB to serial converter that uses the CPU's COM 1 input, disconnecting the RJ12 port on the side.

Joe T.

[krolikbest]

Hi,

I know but there is not problem with com1-usb.  the question is why with disconnected com1 i can set output (O0) ON but with connected i can't if the

--/ MB113/--(O0)-

is in subroutine?  But if i put this above in the main routine it works regardless of the rs232 cable (connected or disconnected)..

[krolikbest]

Solved. Explanation: previously I loaded Displays and subroutines via ladder (but I don't know what could I do wrong in this way) instead of use jumps and triggers. Now it works excellent.

Martin