siemens plc altivar 61

Hi all. Im having a issue with a dryer and need some help. Im not familiar with siemens at all, but it appears im getting a run signal to the drive thru profibus but for some reason the drive is not staying in run mode. Im thinking it could be a profibus issue but im not getting any bus faults on the plc or drive any suggestions

Firstly, I'm not a Siemens guru. But I do know the altivar drives reasonably well. My experience is all with modbus tcp though.

When you say "not staying in run mode", does it actually start at all? If it does rotate the motor, how long before it stops?

If someone had configured the comms timeout to very short time, as well as setting the response to freewheel stop, then it may look like there is no drive fault when really there is a timeout issue. The drive must keep getting scanned via the io card once a run signal is received otherwise it will take action based on the fault response selected.

Was this machine running normally before?

When looking online the bit comes on for a while but the drive never goes into run. It just stays in nst mode. Then the program looks for a pressure switch to be made but since the motor never starts it faults the process no pressure.

Also we had changed the profibus connectors about 2 weeks ago. But it has been running normal. Problem just started a day or so ago. I almost think it could have something to do with the connectors but I would think you would have a bus fault or the drive would be red instead of green on the side of the display

i not familiar with this stuff,

if running well,not program change/modified or replacement on both side possibility error on inverter,

but if profibus send a command word ,PLC always looking feedback/run signal (if program available).

PLC will activate alarm.

compare with another inverter using same method.

In the project open the hardware, go online, select the drive, select properties. If you suspect it is a bus issue you will see something here. Also check the Plc diagnostic buffer for problems.
do you have ob86 in the project?
If you never get a bus fault it is unlikely the the cabling or connectors.
Hard to tell you what it will be without seeing your code.

let me pull up the program. i have a hard time getting around siemens software. alot more familiar with ab

yes there is a ob86

Check this first before go to PLC