CThornton

Unconfigured I/O Address Used

12 posts in this topic

Hi All, 

I am encountering an issue with my Allen Bradley MLX 1200 processor when trying to use the integrated PLC I/O channels I:0.4 - I:0.13 I am getting the error "Unconfigured I/O Address Used". 

I'm using RSLogix 500 to program the PLC. 

I have tried to configure the I/O however it doesn't seem to allow me to 'Activate/Configure' I/O past I:0.3.

Has anyone seen something like this before? 

 

Thanks

CThornton

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The 1200 doesn't have I/O past I:0.1 on it's base unit.  Are you using expansion I/O?  Can you attached your program?

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I do have expansion I/O however I'm maxed out. 

I'm using the 1762-L24BXB which states that it has Input channels 0-13 and outputs 0-9. 

I've uploaded the image from the manual which shows the channel config. 

Thanks

1762-L24BXB.PNG

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The I/O is addressed as I:S.W/B where S is the slot, W is the word, and B is the bit.  So you Inputs are I:0.0/0 - I:0.0/13 and your outputs are O:0.0/0- O:0.0/9.

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If I enter the address as I:0.0/0 I then get the error "Address must be specified to word level". 

 

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I which ladder instruction are you typing this into?  Some do require word level and will not accept bit level addressing.  If you need the status of that specific bit, you might have to move (MOV) to another integer valve, something like N7:x and use that in the ladder instruction.

Quite often as you type in the address and dropdown window will show you the next available address.  If you don't see it indicating the next available bit, then the instruction is looking for a word level address.

Post you program and we'll know how to better answer your question.

By the same token, the instruction help will tell you the acceptable addressing and format for each element in the instruction.

Edited by pcmccartney1

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Here's the instruction I'm trying to type it into. It works for I:0.0-I:0.3 however past that it doesn't.  I've attached 2 rungs, 1 working and 1 which isn't. 

Logic.PNG

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I looked at your program.  Open the data file I1. It will show you which input words are available. There are 4 words of inputs available at slot 0, 0.0-0.3. These should be the built-in inputs. The next input word is I:1.0, which is part of a 4-channel Thermocouple input module. Are you trying to get information out of the 1762-IT4?

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I've had a eureka moment! I was trying to add a discrete input signal to a register which, now thinking about it, obviously wouldn't work. I have replaced the discrete signal with analogue signals which are introduced earlier in the ladder logic. This has corrected the issue. 

 

Thanks for all the help guys. 

 C

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Glad you got it working. Thanks for letting us know.

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