S7-1200 - Scheduleplan start a program every monday at 7.00

Hi,

I am working with the TIA and found that there is OB for "Time of Day" that I was thinking to use.

I want to do this.

Every monday at 7.00 I have to start a program, that opens/close some valves for test, while main program is running.

I thougt of only setting a bit ex M0.0 in an OB of "Time of Day". I reset M0.0 in the main program when finished.

Is it the way to do It or should I do compare of day/time in mainprogram?

I can not se how to setup the OB right.
I can choose Execution: Weekly, but how do I setup witch day?

Thank you in advanced

/Dariusch

You choose which day it would run by selecting the "Start Date" right under the "Execution" selection box you've already used to select "Weekly".

What you said about comparing the local time to 7am Monday could also work. I'm personally a fan of using interrupt based programming, but many people would find the time comparison method easier to follow and debug.

Also, make sure you have set the time/date on the PLC in the first place. This can be done via the Online & Diagnostics screen. You might also want to ensure that you have the 1200 time synced to some other device, like a time server, if you need that 7 AM to be maintained accurately. All devices lose/gain time, but I think the 1200 clock is less accurate than average. It does support NTP, however, so you can sync it to a time server very easily, if one is available. I think I've also seen them synced to an HMI or a GPS.