Jump to content

Recommended Posts

Continuity is easy - just connect +24V to one side of the wires one at a time and see if you get it on the other side.  If you have a bundle to check you can switch wire feeds in with relays and make sure you only get one signal on a DI module connected to all wires.

The RTD module only returns temperature from a resistance of about 25 ohms to 267 ohms.  You could reverse-calculate the resistance, but I don't think this is the range you're looking for.

Resistance is not so easy.  Many moons ago I rolled my own ohmmeter with a DC power supply, current limiting resistors, voltage inputs on an analog module, and current sensors into another module. 

I was trying to measure to .01 ohm resolution on wire to make fuses and it kind of turned into a trainwreck.  I learned about thermal drift of a multi-component system the hard way - I could not keep the thing calibrated.

I eventually bought a really nice four-wire ohmmeter with a serial port and multiplexed it between the wires under test - the manufacturer liked it so much they asked if I would write an app note about it-

https://www.tegam.com/wp-content/uploads/2015/10/AN103.pdf

So this is an area I actually know a little more than the average bear about.

This approach may be overkill for what you're trying to do.  Can you be very specific about what you want?

Joe T.

  • Like 2
  • Upvote 1
Link to post
Share on other sites
  • 3 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...