S7, SFB4 IEC TON Question

Hello,

I'm trying to use the IEC timer, SFB4, for the first time and it seems like it's not working properly.

I've uploaded a picture of the timer, showing the inputs/outputs to the function block. As soon as the IN input turns on the count from ET immediately jumps to the time PT, and the output Q turns on.

Does anyone know what could be the problem?

Thanks.

By the way.. I'm using PLC SIM to test this out. Perhaps it's an issue with PLC SIM?

Yes. There is a hotfix that cures the problem.
You have to contact Siemens support to get it.

Upgrade to PLCSIM V5.4 SP1. Its available for download on the Siemens support site
http://support.automation.siemens.com/WW/view/en/27249219