You are not registered yet. Please click here to register!


 
 
plc storereviewsdownloads
This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.
 
Try our online PLC Simulator- FREE.  Click here now to try it.

New Here? Please read this important info!!!


Go Back   PLCS.net - Interactive Q & A > PLCS.net - Interactive Q & A > LIVE PLC Questions And Answers

Reply
 
Thread Tools Display Modes
Old January 14th, 2022, 12:37 PM   #1
lofiwizard
Member
United States

lofiwizard is offline
 
Join Date: Dec 2019
Location: Ferndale
Posts: 1
Micrologix RTD 1762-IR4 Reads as 0 Ohms before correcting

I have a Micrologix 1400 with an 1762-IR4 RTD. I use it to read airbag resistance on seats on an assembly line. I am often getting into a situation where it is reading as a short circuit, when there is not a short. Then it kind of just goes away after minutes. I can't find a rhyme or reason to it. Any ideas would be appreciated. When in this state, any resistance applied across the RTD inputs doesn't read correctly.
  Reply With Quote
Old January 14th, 2022, 07:54 PM   #2
danw
Member
United States

danw is offline
 
danw's Avatar
 
Join Date: Oct 2004
Location: midwest, USA
Posts: 3,247
I am assuming that this used to work properly (no false zero Ohms readings). It sounds like you have tested the resistance module with a known resistance when 'the readings' are acting uip and that the module does not read the correct value of the test resistance.

The highest probablility is that the resistance input module is bad. Then there are far less likely things like intermittent backplane connections, or an intermittent power supply. It is highly unlikely that the PLC program is executing code that reports some other variable unless someone has been working on the program recently,

Replace the resistance input module.
  Reply With Quote
Old January 14th, 2022, 08:31 PM   #3
James Mcquade
Member
United States

James Mcquade is offline
 
Join Date: Oct 2007
Location: Tennessee
Posts: 3,200
Welcome to the forum.

be sure to check the rtd requirements as far as the in series resistance required for testing purposes. you also MUST have multiple resistance masters to check the rtd circuitry for quality assurance. Have you done a gage r & r study?
james
  Reply With Quote
Reply
Jump to Live PLC Question and Answer Forum

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Topics
Thread Thread Starter Forum Replies Last Post
MicroLogix 1400 RTD Module Jason Ozolins LIVE PLC Questions And Answers 8 June 14th, 2016 04:12 PM
Device net reads 0 ohms? dhracer3 LIVE PLC Questions And Answers 2 November 14th, 2015 09:10 AM
micrologix 1400 and 1762 if4 heroek LIVE PLC Questions And Answers 2 June 26th, 2013 05:39 AM
micrologix 1200 input 1762 if4 module mehmetyil_99 LIVE PLC Questions And Answers 6 November 22nd, 2007 03:19 AM
MicroLogix 1500 RTD Module RobertG LIVE PLC Questions And Answers 0 August 31st, 2004 07:08 PM


All times are GMT -4. The time now is 03:58 PM.


.