
Lake Shore Model 332 Temperature Controller User’s Manual
Diode Input Ranges Calibration (Continued)
9. Program the gain calibration by dividing the measured value of the reference voltage by the
value read in the previous step and provide the result using the
CALG
command. Note that the
gain calibration constant will always be within 5% of 1.00000.
EXAMPLE:
Input: A
Range: GaAlAs Diode
Measured Value of Reference Voltage: 7.50002 VDC
CALREAD?
Reading: 7.49852
Constant Calculation: 7.50002 / 7.49852 = 1.00020
Calibration Command:
CALG A,1,1.00020
10. Send the
CALSAVE
command to save the constants in the E
2
prom.
11. Perform calibration on both diode ranges.
Table 8-1. Calibration Table for Diode Ranges
Range
Voltage Reference Output
Reference Voltage Known To
Cal. Command Type Number
Silicon Diode
2.5 VDC
±0.00010 VDC
0
GaAlAs Diode
7.5 VDC
±0.00040 VDC
1
8.10.2.4 Resistive Input Ranges Calibration
Purpose
To determine the input offset and gain errors when the input is configured for the resistive ranges
and provide offset and gain calibration constants back to the Model 332. This step will calibrate all
resistive ranges with reversing both on and off.
Process
1. Configure the input for the resistive range to be calibrated.
2. Reset the calibration constants to their default values using the
CALRSTZ
and
CALRSTG
commands.
EXAMPLE:
Input: A
Range: Platinum 250
Ω
, Reversal Off
Zero Offset Reset Command:
CALRSTZ A,2
Gain Reset Command:
CALRSTG A,2
3. Short all four terminals, (I+, I–, V+, V–), of the input together, do not tie the terminals to ground.
4. Via the interface obtain the input reading using the
CALREAD?
command and record this
number.
5. Program the offset calibration by negating the value read in the previous step and providing it
using the
CALZ
command.
EXAMPLE:
Input: A
Range: Platinum 250
Ω
, Reversal Off
CALREAD?
Reading: +000.003
Calibration Command:
CALZ A,2,-0.003
6. From Table 8-2 select the calibration resistor for the range being calibrated and use the DMM
in 4-lead resistance measurement mode to measure the value of the resistor to the tolerance
shown.
7. Attach the calibration resistor to the Model 332 sensor input. Be sure to connect the resistor
using proper 4-lead connection techniques.
8-14
Service