ILX Lightwave LDT-5525 User Manual page 64

Two Point Calibration Method
This procedure will work for any linear temperature sensor. The accuracy of this procedure depends on the accuracy
of the known temperatures, externally measured. It is used to determine the zero offset of the device and the gain
offset (slope).
1. Allow the LDT-5525 Temperature Controller to warm up for at least one hour. Set the SENSOR SELECT
switch for the desired sensor type, and RECALL the constants for the particular device to be calibrated.
2. Select the C1 parameter. Read and record the value of C1. Select the C2 parameter. Read and record the
value of C2.
3. Place the sensor at an accurately known and stable temperature, T
of the LDT-5525's 15-pin connector. Set the LDT-5525 for normal constant temperature (T mode)
operation. Allow the LDT-5525 Temperature Controller to stabilize at the known temperature, T
read the displayed temperature, T
4. Repeat Step 3 for another known temperature, T
The two known temperatures should at the bounds of the intended operating range. The smaller the
intended operating range, the better the calibration over that same range.
5. Determine the new value of C1 (C1
. Record these values.
d1
, and the corresponding displayed temperature, T
a2
) and C2 (C2 ) from the following calculations.
n n
C-6
. Connect the sensor to pins 7 and 8
a1
and
a1
.
d2