I have a new Micrologix 1400. I have an SCP instruction that should give me a 0-4095 output on O:0.5 address. Problem is it does not ever change the value from 0. If I manually type a value like 4095 into O:0.5 the output will give me 10VDC. I have even tried removing the SCP and replacing with a MOV instruction. The value of the output will not change.
Micrologix 1400 Embedded Analog Problem
- Thread starter dwhit73
- Start date
Bering C Sparky
Lifetime Supporting Member
Hello and Welcome to the forum.
Are you writing this instruction in LAD 2?
If not can you make sure you have a JSR pointed at the LAD that you are writing this instruction on.
If both of these check out, then can you post your program.
Zip it first.
EDIT: OPP's I put rung instead of LAD, fixed it with this EDIT.
Are you writing this instruction in LAD 2?
If not can you make sure you have a JSR pointed at the LAD that you are writing this instruction on.
If both of these check out, then can you post your program.
Zip it first.
EDIT: OPP's I put rung instead of LAD, fixed it with this EDIT.
Last edited:
The instruction is in Lad File 7. I have a JSR for U:7. Other instructions in this Lad File work. The SCP instruction has no permissives and should scale the value of an F:11 register from input 0-100 and output 0-4095. The output is not used anywhere else.
Bering C Sparky
Lifetime Supporting Member
If you can zip and post your file I am sure you will get a solution rather quickly.
Also what is the complete model # of your micrologix.
BCS
Also what is the complete model # of your micrologix.
BCS
dginbuffalo
Member
If your SCP has a destination of O:0.5, and your manually writing 4095 into it without it being overwritten, then "most likely" your SCP is not getting scanned. If it was, your 4095 would be overwrote with whatever the SCP calculated.
Is O:0.5 where the SCP is writing to?
Is O:0.5 where the SCP is writing to?
dginbuffalo
Member
If you tried a move and an SCP, it really seems like that routine isn't getting scanned although you said other logic in it is working.
update- I just looked in the Micrologix instruction help and it says floating point is not supported in the Micrologix 1400 SCP instruction.
scratch update above possibly- it says the "parameters" cannot be floating point.
update- I just looked in the Micrologix instruction help and it says floating point is not supported in the Micrologix 1400 SCP instruction.
scratch update above possibly- it says the "parameters" cannot be floating point.
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dginbuffalo
Member
I'm fuzzy on Micro's because I don't get into much anymore but that's probably why-Your trying to move a 32 bit float into a 16 bit output register. I know you can move into an integer (N) and it will round up or down, but I'm not sure that works into an output? I'm sure somebody can set us straight?
Also - just because the routine is getting scanned, doesn't mean it's getting all the way to that rung. There could be RET or JMP instructions involved, skipping part of the code.
Add a rung directly underneath that one with an XIC OTE. Make sure neither are used anywhere else. Toggle the XIC and the OTE should come on - if it doesn't you know that something's stopping the logic scanning down to that point.
Add a rung directly underneath that one with an XIC OTE. Make sure neither are used anywhere else. Toggle the XIC and the OTE should come on - if it doesn't you know that something's stopping the logic scanning down to that point.
I have several Micrologix 1400 using the SCP instructions with floating points as the input that work fine with the built-in analog outputs. The SCL instruction requires a interger to work. If you are using SCL try replacing with the SCP.
Firejo
Member
I’ve done what you’re trying to do except that the destination from the SCP was to an integer and then I moved the integer’s value to the analog output. To be fair the other difference was that everything was done in LAD 2. If you haven’t yet come up with the fix you might try changing the destination to an integer and then move it to the output. At very least you’ll be able to see if the SCP is being scanned. If the integer value changes but the output doesn’t you’ll know that the SCP is doing what it’s supposed to but something is taking hold of the output. With that said if you’ve got something in LAD 2 that is driving the output you’ll probably need to disable it when the LAD file with the SCP is active.
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