Output Calibration

Accurate retransmission of the selected parameters can only be obtained through calibrating both of the analog outputs.  This is done at the factory prior to shipment, however it is a relatively simple procedure that can be performed in the field if desired.  To perform a calibration, a multimeter with a current input is required.  Please keep in mind that the accuracy of the instrument used to calibrate the outputs is directly related to the accuracy of the outputs after calibration, so a meter calibrated against NIST (National Institute of Standards and Technology) standards is preferred.  Before performing any calibrations, all other devices must be disconnected from the analog outputs.  Multiple devices on the outputs will cause inaccurate measurement of current.

 

Attach the leads of the multimeter to the terminals for Output 1.  The positive lead should be attached to Terminal #1121 and the negative lead to Terminal 1111.  Select “Zero Output 1” and press the “Prep for Cal” button.  The low limit of the output is 4mA, so 4.000 is shown as the default measured value.  Ideally the meter connected to the outputs will also show 4.000.  If the two values are not close enough to obtain the desired level of accuracy, a calibration should be performed.

 

If, for example, the meter connected to the outputs reads 4.216mA, then the value “4.216” should be entered on the screen as the Measured Value.  Once the value has been entered, press the “calibrate” button.  This will offset the mA output of the instrument in an amount that results in an exact output of 4.000mA.  When the calibration is complete, the multimeter should be reading 4.000mA (+/- .005).

 

The procedure can be repeated for the Span of Output 1.  When “Span Output 1” is selected and “Prep for Cal” is pressed, the instrument will output the high output limit, which is 20mA.  The multimeter will display the actual output from the instrument, and if it is not within the desired tolerance it can be calibrated using the same procedure as above.

 

To calibrate Output 2, attach the leads of the multimeter to Terminal #1121 (+) and the negative lead to Terminal 1131 (-) and follow the same procedure that was used for the first output.