User manual

Toolbox 32 User Manual 1.47d www.cse-semaphore.com/mykingfisher
Page
222
Calibration Method
• Select the Reset button. This will clear the calibration registers in the RT-1 module. If this operation is
successful the message "Reset Successfully" will be displayed.
• Connect a resistance to the RT-1 corresponding to the resistance of the Pt100 at a known temperature.
• Select the Check Temp 1 button.
• Enter the temperature corresponding to this resistance (the allowable range is -150 to 400ºC).
• Connect a resistance to the RTU corresponding to the resistance of the Pt100 at a second known
temperature.
• Select the Check Temp 2 button.
• Enter the temperature corresponding to this resistance (-150 to 400ºC)
• Select the Calibrate button. If the setpoints are in range, they will be sent to the RT-1 module and then
the message “Calibrate Data Sent Successfully!" will be displayed.
RT-1 Scaling
Say the resistance of a Pt100 device at -150ºC is 40 Ohms and at 400ºC is 250 Ohms. After resetting the
RT-1 module, these two resistances might be displayed in Toolbox as 7% and 83% respectively. By entering
-150ºC for Temp1 and 400ºC for Temp2, and calibrating the RT-1 module, the 40-250 Ohms resistance
range would then be displayed as 0-100% in Toolbox.
When the Check Temp1 or Check Temp2 button is selected, Toolbox records the current input percentage.
These input percentages are then used with the temperature setpoints to determine an input/temperature
characteristic. The figure below illustrates the input/temperature characteristic of a correctly calibrated
module.
-150 400
Deg C
%
100
Figure: Output from RT-1 Module After Calibration