Fluke Process Instruments

The Endurance sensor, when used with the Field Calibration section of the DTMD software will set the mA output to 4mA (or 0mA if using the 0-20mA) and then 20mA. If necessary, offset and  gain adjustments are applied so that the sensor will output 4ma and 20mA. 

In addition one can set a value any 1mA increment between  0/4 and 20 mA,  via the Current output section in the 

Configurations list:

To Set: Type in the value and then hit Set. When finished, select Device Controlled.

Note that on power cycle, the sensor will always revert to Device Controlled.

Primary Reason To Use

The primary  reason to set specific values for the mA output is to calibrate the analog output at intermediate points between 0/4 and 20mA to provide confidence that the mA value will match (within the specification of the sensor) the digitally calculated value (display and DTMD, ASCII, Profinet and EthernetIP.

The alternative to this would be to check at each temperature point, the mA value. 

Example:

This would then allow (if necessary) the analog output stage to be adjusted via the Field Calibration mA adjustment function See Article or via DTMD: 

Or via OUO and OUG commands.

Please note that the Field Calibration function simply calculates and sets these offset and gain parameters. Therefore, using the Field Calibration function within DTMD is not mandatory. If, for example, your process is only using a small part of the mA range, one can define offset and gain values in order to get the best performance (or least deviation from the digital value).

Secondary Reason To Use

The secondary reason is to use the sensor to drive a fixed signal into a control system or PLC (like a mA injector). The control system can then be checked against the scaling of the sensor that the displayed value is matching the applied mA signal.

 The use of dedicated  mA process calibrators are highly recommended

The exact model will depend on the resolution of the mA signal you need to measure (typically 10uA or better) 

Note: The  Endurance has 0.1K measurement resolution (analog and digital)

 Consider reducing the scaling of the mA output to give larger signal step changes

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