Is there also a equivalent for S_OFDT? I need to do a off delay of 12 hours. Thanks in advance!

dchartier

Hello pb01;
I agree that timers you find in the Timer instructions of Step 7 (S-ODT, for example) are limited to the range of the S5Time variable, that is a little ove 2 hours.
However, if you open the SFC/SFB library instructions, you can look at SFB4, "TON", which uses a Time datatype for the preset and accumulated time of the timer,
TIME is an IEC32-bit datatype, actually an integer value reperesenting milliseconds, which makes it very useful for timer math, but also gives you a range of up to 24 days.
So you could call SFB4 (in STL, for illustrative purposes, you can use it in ladder without prtoblem) this way:

Call SFB4, DB 40 // you will need to generate an instance DB for the function block

IN: M10.0 // start counting signal, boolean
PT: T#0D_24H_0M_0S_0ms // Preset time in TIME format T#, set for 24 hours (or T#1D)
Q: Q2.0 // output to be activated when the timer reaches the preset value, boolean
ET: MD100 //double integeraddress for accumulated time of the timer; you can monitor this

Hope this helps,
Daniel Chartier

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Split from S7-300 timer for at least 24 hours.