Hello, I'm working with a micrologix 1500 with a 1769 16 point input card. The problem I'm having is that I'm getting an input when there is no signal coming from PX switch. I can remove the input wire off the terminal and I still have the input light lit and when viewing it on the laptop, XIC contact is showing that it is on. The input is sourcing and when I do give it a signal the input stays on. All other inputs are working correctly. Has anyone experienced this problem before. If I down load the code again will it clear it up. Thanks for the help.
Input on without giving plc a signal
- Thread starter Linwo5
- Start date
Bit_Bucket_07
Member
That behavior typically indicates a failed point on the input module.
Steve Bailey
Lifetime Supporting Member + Moderator
I don't know the MicroLogix 1500 well, so this may not be pertinent. Is it possible that there is another input module configured for the same address as the on that shows the problem?
When you replaced the input module did you reuse the wired terminal strip from the original module? It could be that one of the other inputs is shorted to the one you're experiencing problems with. Try removing wires one at a time until the input goes off.
If you remove the terminal strip from the module does the input turn off? Is the terminator cap in place at the last 1769 module?
When you replaced the input module did you reuse the wired terminal strip from the original module? It could be that one of the other inputs is shorted to the one you're experiencing problems with. Try removing wires one at a time until the input goes off.
If you remove the terminal strip from the module does the input turn off? Is the terminator cap in place at the last 1769 module?
What is the state of the input module LED ?
input card
hi, can you get into the program. If so, best thing to do would be to use a spare input and change input in program. Also check other inputs on card, ones you know go to this card, check they go on and off ok, to make sure its not configuration of card.
hi, can you get into the program. If so, best thing to do would be to use a spare input and change input in program. Also check other inputs on card, ones you know go to this card, check they go on and off ok, to make sure its not configuration of card.
TConnolly
Lifetime Supporting Member
I'm glad you got it working, but I wanted to add one more thing that wasn't mentioned to this thread in case someone has a similar problem in the future.
If you have the input image word addressed by an OTE or OTL instruction or a MOV, masked moved, SQO, or any math instruction
then the input bit will appear to true in RSLoigx500, regardless of what the physical state of the wired IO point is. Conversely, if anything is your program clears the bit, it will appear to be off regardless of the physical IO state.
If you have the input image word addressed by an OTE or OTL instruction or a MOV, masked moved, SQO, or any math instruction
I:0/0
----------( )---
or
----------+MOV------+
| N7:0|
| I:0.0|
+---------+
then the input bit will appear to true in RSLoigx500, regardless of what the physical state of the wired IO point is. Conversely, if anything is your program clears the bit, it will appear to be off regardless of the physical IO state.
Similar Topics
I have a numeric input field on my HMI. That field is being focused and written to by a macro keyboard so the operator doesn't actually enter a...
Hi;
In numeric input field in Rs View32 works, after writing a value, if we don't press the Enter button from keyboard, value doesn't load. Is...
I'm trying to take an input signal (boolean, not analog), delay it for a configurable amount of time, then output it via an AOI using as little...
Hi, I have a ControlLogix system with 1756-IF16 analogue inputs. I can't scale the inputs at the card as there is a requirement to facilitate...
I'm having trouble calming down 2 Tempo Sonics. I'm using Studio 5000 CompactLogix my Raw value is jumping around from 8575.0 to 8755.0 at a...