Studio5000 AOI and Latching

Bbarnett · Jan 20, 2021

I am curious why my latches do not work and maybe someone here has some insight.

I have created two AOIs. One AOI latches an output on (ON). The other AOI unlatches an output (OFF).

The same output is set to both AOIs so that one AOI latches the output on and the other AOI unlatches the same output.

The ON AOI is read first.

When I run the routine, the output never turns on.

Is latching/unlatching the same output a shortcoming with AOIs? It's like the AOIs are treating this output as an OTE and not OTL/OTU.

drbitboy · Jan 20, 2021

What happens if you remove the rung with the second AOI, or set the rung to false e.g. put an AFI, (or [XIC output XIO output]) on that rung just before the second AOI?

Alternatively put in a counting rung e.g. [XIC output LES dint_counter 1000000000 ADD dint_counter 1 dint_counter] after the latching AOI and before the unlatching AOI; if the first AOI is not latching the output, then that counter will not change.

Ron Beaufort expained it very well a while back, cf. https://www.plctalk.net/qanda/showthread.php?p=5971#post5971.

Phrog30 · Jan 20, 2021

The way I read your post, it's doing exactly as you programmed it. If the 2nd is turning it off and it's last, it's going to be off.

I_Automation · Jan 20, 2021

In this instance do you want the latching AOI to 'win' or the unlatching AOI?

If latching, then move the unlatching AOI call before the latching AOI.

Rich Wargo · Jan 20, 2021

What form is output instruction in AOIs? If you are using a standard coil (OTE) in AOIs, then it will ALWAYS write input condition to memory location represented by the coil address. That is purpose of OTL and OTU instructions, they only set (or reset) when input condition to coil instruction is ON.

daba · Jan 20, 2021

Bbarnett said:
I am curious why my latches do not work and maybe someone here has some insight.

I have created two AOIs. One AOI latches an output on (ON). The other AOI unlatches an output (OFF).

The same output is set to both AOIs so that one AOI latches the output on and the other AOI unlatches the same output.

The ON AOI is read first.

When I run the routine, the output never turns on.

Is latching/unlatching the same output a shortcoming with AOIs? It's like the AOIs are treating this output as an OTE and not OTL/OTU.

Can you export and zip your AOI's ?

Studio5000 AOI and Latching

Bbarnett

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drbitboy

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Phrog30

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I_Automation

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Rich Wargo

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daba

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