4-20ma transmitters revisited.

Just got a few of these in and had the opportunity to try one out today. It worked very well (at 24 VDC)

http://www.ebay.com/itm/381740526079?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT

This is my go too: https://www.theautomationstore.com/analog-digital-simulator-0-10vdc-and-4-20ma/

Well worth the price!

rootboy said:

Just got a few of these in and had the opportunity to try one out today. It worked very well (at 24 VDC)

Click to expand...

Hard to come close to that price...

Paully's5.0 said:

This is my go too

Click to expand...

I'll throw my hat in the ring.... https://www.plccable.com/electrical...t-generator-4-20-ma-0-10-vdc-with-case-leads/

I've got the IP Explorer, and I love the thing! Both of the other devices are pretty sweet too.

But like you said, you can't beat the price of these things. And I regularly lose track of little trinkets like these somewhere near the engineer or maintenance folks desks, so cheap is good...

I just bought one of these:

http://www.newark.com/analog-devices/eval-cn0179-pmdz/evaluation-board-process-controller/dp/53X9919

Which I intend to strap to an Arduino or a Pi and a LCD display. Something to play with...

Not cheap but I love my fluke 772. Can source and read it both with the clamp or in series.

Does the Hong Kong simulator have a working digital display?



I noticed that none of the product photos show the display actively displaying a value, so maybe it's just a blind simulator?

danw said:

Does the Hong Kong simulator have a working digital display?

I noticed that none of the product photos show the display actively displaying a value, so maybe it's just a blind simulator?

Click to expand...

Looks same for me, even same price. One disadvantage is that there is no passive output.

http://www.ebay.com/itm/DC-12V-24V-...775659?hash=item25c37159eb:g:ZzAAAOSw8oFXzdCR

I bought five of the simulators shown in the graphic image above and just finished testing them out-of-the-box.

Observations:

a) the digital display reads to one digit to the right of the decimal point, ie, to 0.1. The sales description mentions 0.01, but the hundredths digit is not displayed. The photos do not show powered displays so it isn't obvious what the display resolution is.

b) The generated signals are off by a 0.1mA or 0.2mA (measured with a calibrated mA calibrator), so the device is not a calibrator, it's an indicating source. There are no adjustments to correct zero or span.

I used a regulated 24Vdc power supply to power them up for a test out of the box. I plan on using two 9V batteries in series as a day-to-day power supply. The field connections are on a Phoenix Contact style removable connector which made testing easy.

I am not complaining. For $10-12 each, they are perfect for sourcing a mA signal. But I thought the resolution and approximation output worth clarifying.

Builded this: http://www.plctalk.net/qanda/showpost.php?p=417573&postcount=24 several years ago with couple improvements to Roy's original design.

Powering with 2*9V battery, 4,8,12,16,20mA is maded by rotary switch and power is selectable of internal 18Vdc or external source.
Thinking that I also added resistor between reference and common, so that output is more accurate also if batteries are not full.
mA outputs can be calibrated with multiturn potentiometers. It was possible to calibrate exactly to correct output.

Parts costed somewhere around 5-15$, if someone needs diagram, I can check if saved somewhere