RayK
Member
As per the attached image would this be a good way to test an analog input Card? using a 1/2 watt 2k resister to give roughly 50% FSD on 4 to 20 ma.
Test setup for a 162-IF4
- Thread starter RayK
- Start date
Mickey
Lifetime Supporting Member
With the internal resistance of each channel at 275 ohms, see picture below. The current will be about 8ma ( 7.7ma ).
I would prefer to test each channel and be able to vary the current up/down myself.
I would prefer to test each channel and be able to vary the current up/down myself.
geniusintraining
Lifetime Supporting Member + Moderator
Hi Ray,
Not sure if you are in the market to spend money but if you are we sell these http://www.ebay.com/itm/370283656400 and they would work very good for this
This would give you several for each channel
Not sure if you are in the market to spend money but if you are we sell these http://www.ebay.com/itm/370283656400 and they would work very good for this
This would give you several for each channel
RayK
Member
OP
Ohms law!
Thanks for that Mickey I was forgetting about loading and ohms law, so if I drop the 2k resister and used 900ohm would achieve my 12ma 50% fsd!
Git: cheaper option would be an LM317 at $2.50 2 diodes at 20c a resister at 6c and a 10k pot at $2.10 ! Aussie prices! total $4.86.
Thanks for that Mickey I was forgetting about loading and ohms law, so if I drop the 2k resister and used 900ohm would achieve my 12ma 50% fsd!
Git: cheaper option would be an LM317 at $2.50 2 diodes at 20c a resister at 6c and a 10k pot at $2.10 ! Aussie prices! total $4.86.
RayK
Member
OP
1762-if4
As an aside to this is it OK to power these modules up open circuit?
As an aside to this is it OK to power these modules up open circuit?
Mickey
Lifetime Supporting Member
Don't see why not.
It is usually a good idea to short unused channels to prevent noise on the other channels.
TimWilborne
Lifetime Supporting Member
Interesting, I had never heard of this. Got anywhere I can read up on it?
Mickey
Lifetime Supporting Member
See picture below, its a snapshot of the manual for a 1771-IFE. I have seen this same note in other analog card manuals.
And a PDF for SLC input modules.
And a PDF for SLC input modules.
Last edited:
TimWilborne
Lifetime Supporting Member
Thanks, good info
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