adccommunitymod (AutomationDirect) asked a question.
Output Staying On
Created Date: February 22,2014
Created By: robertkeenan
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I have a problem with the stage in a DL06 PLC. If a stage is active and has an output C325, then after a power cut the stage is off but the output is still on. Should it not be that if the stage is off then everything in the stage will also be off. C325 is then used to turn on a physical output Y106. PLC is D0-06DR and CPU version V2.60
Created Date: February 22,2014
Created by: bcarlton
Zip and post your program. I typically program a rung or subroutine activated by 'First Scan ' to reset stages and outputs as needed.
Created Date: February 22,2014
Created by: BobO
I have a problem with the stage in a DL06 PLC. If a stage is active and has an output C325, then after a power cut the stage is off but the output is still on. Should it not be that if the stage is off then everything in the stage will also be off. C325 is then used to turn on a physical output Y106. PLC is D0-06DR and CPU version V2.60
I don't know precisely how Koyo implemented Stage, but I suspect that since the stage is off following the power failure, the code that would normally run to clear the OUT instruction following the stage turning off will never run and never clear the OUT. Simple answer is that if a stage is not retentive, don't use a retentive parameter in an OUT coil.
Created Date: February 23,2014
Created by: LWgreys
It sounds like you used the SET command to turn C325 on and not the OUT command. SET will turn on any output until the output is reset with RST.
Even if the stage it was turned on is disabled that output will remain ON.
Created Date: February 24,2014
Created by: scott.lawrence
then after a power cut the stage is off but the output is still on.
if you use a lot of set/reset coils, you need a subroutine that fills all output/c-bit words with 0 triggered by First Scan. Think of it as a rest...
Created Date: February 24,2014
Created by: plcnut
It is possible for an OUT coil to remain on after leaving a STAGE. I have dealt with it in the past, but cannot recall the exact fix. I do believe that it had to do with proper structuring of stages.
One fix (as long as you are NOT using SET/RESET's as latches) is to place a RESET in the top of your ladder for each of the outputs. This way, all outputs in the program will remain off, unless explicitly turned on during that ladder scan.
Created Date: February 22,2014
Created by: robertkeenan
I have a problem with the stage in a DL06 PLC. If a stage is active and has an output C325, then after a power cut the stage is off but the output is still on. Should it not be that if the stage is off then everything in the stage will also be off. C325 is then used to turn on a physical output Y106. PLC is D0-06DR and CPU version V2.60