TIA V13 SP1, IEC_TIMER and TON_TIME not working like expected

Hello,

I have a similar problem maybe you can help me.

I have a 1215C V4.1 with TIA V13 SP1

I treid both the IEC_TIMER and TON_TIME but none working like expected.

In network 4 the signal #Ton1.Q is not raising to trigger P_TRIG

If I do it this way it works perfect:

Any idea what the problem is?

greetings

Jens

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Split from TON timer not working.

Hello,

thank you for the answer but it is not clear to me.
I expect the following:

1. IN is true
2. Timer will set Q to true after 1 sec.
3. next network Q is still true cause it is still the same PLC cycle.
4. P_TRIG will shoot
5. Cycle comes back to TON_1 but will reset it
6. Starts to count again

What do you think?

greetings Jens

Hello.

I don't know the technique of the 12xx, but at the 15xx the IEC-Timer are integrated into the system.

The TON-call ist not a subroutine as by the 3xx/4xx, it is a initialisation call.

So the TON1.Q will not set by the call, it will be set by system exactly wenn time is expired.

In your case TON1.Q is already true when network 3 is executed and will be reset in the same network.

Siemens recommend to use the Q output of the call instead of TON.Q

JoernSchr

Hello.

I don't know the technique of the 12xx, but at the 15xx the IEC-Timer are integrated into the system.

The TON-call ist not a subroutine as by the 3xx/4xx, it is a initialisation call.

So the TON1.Q will not set by the call, it will be set by system exactly wenn time is expired.

In your case TON1.Q is already true when network 3 is executed and will be reset in the same network.

Siemens recommend to use the Q output of the call instead of TON.Q

 I think so too.

The TON.Q is set at any time in the cylcle. But before you whant to use it you reset it. 

regards,

You have nothing connected to the timer outputs (.Q or .ET) in your first example, so the timer will not execute. You need to connect something to make it go. I guess that Siemens thought that if you don't connect anything, you don't want it to do anything so it doesn't need to run.

I don't understand why, but that is how it is.

Brian

brian.grimshaw

You have nothing connected to the timer outputs (.Q or .ET) in your first example, so the timer will not execute. You need to connect something to make it go. I guess that Siemens thought that if you don't connect anything, you don't want it to do anything so it doesn't need to run.

I don't understand why, but that is how it is.

Brian

 thats wrong!

There is no need to connect anything on Q or ET

You can try it by yourself, by simulation on PLCSIM and view the block online. 

regards,

jjjmuniz is very right. The IEC timers in S7-1200 and 1500 don't work as they used to in S7-300/400.

Jensen81, in your first solution in fact the timer is executed twice. That's why you can't register the state change of the Q.

TIA Information System: "The instruction data is updated both when the istruction is called and also each time the outputs Q or ET are accessed."

I have tried it myself, and the results are variable. See this one too:

https://support.industry.siemens.com/tf/ww/en/posts/ton-timer-e-g-behaves-not-like-i-used-to-on-other-systems/140208/?page=0&pageSize=10

There are more on here too stating the same thing. The only way to guarantee operation seems to be to put a coil on the output.

Brian

Oh dear, does it differ per system? Is it a bug or a feature? Programming is becoming an art!

It's somewhat documented wrt self starting timers but amazingly the description of this behavior is longer than that of the timer itself. 

I agree and duly put a extra temporary at the Q output in the hope it will behave I expect. At a 1200 that is.