Model TT231-0600
Two-Wire RTD Transmitter w/USB
Acromag, Inc. Tel: 248-295-0880
- 21 - http://www.acromag.com
- 21 -
http://www.acromag.com
Zero, Full-Scale, &
Linearizer Calibration
Procedure…
Zero, Full-Scale, & Linearizer Calibration Procedure…continued
3. (Pt RTD Input only) After clicking “Go to Step 3”, the following message will be
displayed:
Step 3 reads just like Step 2, except the RTD linearization circuit has been
activated and your output signal shifts closer to your desired full-scale output
level. Click OK and this message is repeated in the prompt window at the
bottom of the screen. The transmitter needs your output reading with
linearization enabled to adjust the RTD linearization correction current for the
sensor excitation. You don’t need to readjust your input signal at this step, as it
uses the same full-scale input from the prior step 2.
Simply measure your output signal and input the new measurement taken
(note that it will be closer to the full-scale output than it was in step 2, as
linearization is ON). Type the measured output current in milliamps into the
Measured Current Output field. Then click the Complete Calibration button
and the following message will appear (your output may shift slightly to reflect
an adjustment to linearization):
At this point, the transmitter is calibrated. Click OK to
continue. Check the accuracy of a few other points.
Note that if your input type is Pt RTD, your output will
be linear with the input temperature, not the input
resistance.
If your output appears imprecise, you may need to repeat calibration, but being
very careful to take accurate measurements and enter the measured output
currents correctly, and using milliamps as your units. Make sure that you
carefully drive the precise input signal resistances necessary for calibration. If
measuring voltage across the output load resistance, make sure that you use
the exact input resistance when calculating the current measured. Also, make
sure that you have an adequate input span, as too-tight input spans will
magnify error.