NOSHOK 920 Series RTD Transmitter Software User Manual - Manual (Page 9)

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The next step is the adjustment of the 20 mA. To perform that operation, simply
click on the 20 mA button located in the CURRENT ADJUSTMENT section of the
“Programming” window. This will force the RTD Transmitter output to the theoretical
value of 20.00 mA.
Once the button is pressed, a small dialog box appears on the screen ( Figure 3-B)
allowing the user to set the output current, by clicking on the “+” or “-” button, to
read exactly 20.00 mA on his loop current indicator. When the indicator reads 20.00
mA then click on the “Set” button to record the new value in the RTD Transmitter.
The last step is the calculation and recording of the output adjustment parameters.
This is performed by clicking on the “Process” button located in the CURRENT
ADJUSTMENT section of the “Programming” window. The 920_Prog Txr program
then reads the 4.00 mA and 20.00 mA values that have been set earlier in the RTD
Transmitter, calculates the adjustment parameters and uploads the new values in
the RTD Transmitter memory.
The current adjustment can be performed at any time and not necessarily in order
(i.e. the 20 mA output adjustment can be performed before the 4 mA adjustment). If
necessary, only one of the 4 mA or 20 mA can be performed. When the current
adjustment parameters are calculated, the values are taken from the RTD
Transmitter memory.
Sensor Failure Settings:
The failed value represents the output value at which the transmitter will be set if a
failure is detected on the Resistive Temperature Detector. The two available
choices are “<2.5 mA”, which correspond to an output of about 2.5 mA or lower, and
“>24 mA”, which correspond to an output of about 24 mA or higher. To set the failed
value click on the radio button, in the SENSOR FAILURE SETTINGS section,
corresponding to your choice and then click on the “SET” button, located in the
same section, to update the setting in the RTD Transmitter.
Calibration:
By default, every RTD Transmitter is calibrated at one point at the factory but the
user can, with the help of the 920_Prog Txr software, re-calibrate or re-scale the
RTD Transmitter. Two types of calibration are available through the 920_Prog Txr
software. The first one is the “One point” calibration, which allows the user to
calibrate the RTD Transmitter against one known temperature value in the operating
range. The second type is the “Two point” calibration, which allows the user to
calibrate the RTD Transmitter against two known points in the operating range.
920_Prog Txr
User’s Manual – Preliminary Version