Learn How to Calibrate GEMS' 4-20 MA

Hi, I'm Tim Kelley from Gems Sensors, the product sales manager for our continuous and connectivity product lines. What I'm here today to talk to you about is calibrating our 4 -20 mili-amp signal conditioner.

The conditioner I have in front of you here is commonly found with our float type transmitters and our SureSite product line. To do the calibration, what you'll need is a 24-volt power supply DC voltage, a multimeter, a screwdriver or tweaker, and a potentiometer in the range of 1,000 Ohm to 25,00 Ohm. To wire this up properly you'll take your 24-volt positive DC into pin 5 pin 4. We'll go to your multimeter, your common leg of the multimeter back to your negative leg of the DC power supply and the potentiometer into pins 1, 2, and 3. The red into 1 black into 2 and the third will have the wiper arm or the light wire.

Once you have your potentiometer connected, we want to establish the direction of raising and lowering its output turning the potentiometer. Clockwise you'll notice on the multimeter that the output goes towards 20 milliamps. Counterclockwise the output drops towards for millions. Let's raise it all the way clockwise. Once we've done that, we now can adjust on the span potentiometer and tweak that down towards the 20 milliamps. Once that's done, we take the potentiometer fully counterclockwise and do this to the potentiometer. Now these do affect each other so what we want to do is these two or three times total. If we bring the potentiometer fully clockwise, you'll notice that the output is changed, and we tweak that back towards the 20-milliamp point. As I said doing that two or three times will pull that into your four and 20 points. Once you're done your unit is fully calibrated.

If you do not have a potentiometer handy you can replace that by using a simple jumper wire placing it from terminals two and three to set your four milliamp point and one in three to set your twenty-milliamp point. Once you've completed the calibration process the signal conditioner is ready to be used on transmitters of any length. Should you have any questions on this calibration procedure or any technical questions on any Gems product line feel free to give us a call.