Why can't i get a mili Amp mA value from this leveltransmitter

• May 7, 2022

• Thread starter
• #2

BOUFEK

Electrical

Feb 2, 2022

3

NG

please I also tried using a clamp meter it didn't work, please is there any way else I can test if this device is working or not, thank you I really appreciate your contributions to and suggestions.

 

Upvote 0 Downvote

• May 7, 2022

• #3

IRstuff

Aerospace

Jun 3, 2002

44,911

US

Your DMM's input impedance is too low for a current loop measurement. You need to properly terminate the current loop to measure the correct current.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

Upvote 0 Downvote

• May 7, 2022

• #4

itsmoked

Electrical

Feb 18, 2005

19,114

US

Is that even a pressure transducer or is it an ultrasonic transducer? If pressure it's cable length is absurd.

Have you got a model number for this?

 

Upvote 0 Downvote

• May 7, 2022

• #5

3DDave

Aerospace

May 23, 2013

11,502

US

IRstuff - he wrote that he has this in series, so shouldn't the impedance of the meter be low?

I first thought he was using this to read the sensor directly and didn't apply the loop voltage, just the voltage to power the sensor, but when he mentioned series connection I thought that might not be the case.

A model number for the sensor would be a big help; maybe he will call in again.

 

Upvote 0 Downvote

• May 7, 2022

• #6

danw2

Industrial

Oct 21, 2004

1,528

US

A photo of a housing with a probe does not identify what technology or what type of transmitter is involved.

Is it a 2-wire loop powered transmitter?
Or is a 3-wire voltage output transmitter?
How do you know the output is 4-20mA and not Profibus, Foundation Fieldbus or Modbus?

If you have powered a 2-wire loop powered transmitter properly and connected the millammeter properly, then the device is not working properly because a 4-20mA loop powered transmitter never goes 0mA. It might fault low at 3.6mA, it might indicate a below zero (eng units) level at 3.9mA, but a 2-wire loop powered transmitter uses 3.5mA of the loop current to operate so it can NEVER have less than 3.5mA if it's working properly.

 

Upvote 0 Downvote

• May 7, 2022

• #7

IRstuff

Aerospace

Jun 3, 2002

44,911

US

IRstuff - he wrote that he has this in series, so shouldn't the impedance of the meter be low?

Click to expand...

In series with WHAT, though? He made no mention of a receiver, so it's likely the transmitter detected a dead short, in which case I could see it shutting off the output altogether

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

Upvote 0 Downvote

• May 23, 2022

• Thread starter
• #8

BOUFEK

Electrical

Feb 2, 2022

3

NG

Hi guys good evening from Nigeria,
Actually I didn't get a timely response from this group, anyway regarding the transmitter I posted the other day, I discovered when I opened the back the terminal A and B were not connected to the electronic circuit, it was the test point A+and A- that was connected and the PLC was wired in a way that the blue cable was positive and red negative (0) so after changing the connection to the right terminal and reversing the connection that is red to A- and blue to A+ I started to get value on the transmitter, we have called expert to come do the calibration... And regarding the length of the probe,it is a level transmitter and it is used for a tank not up to 1 metre so I guess that is why the cable is short...

Thank you for your time, input and understanding...

Like I said earlier I am a fresher I want to grow I want to learn mostly instrument and automation, please guide me in the best way you can.

Thank you once more lot of love from Nigeria.

 

Upvote 0 Downvote