Changing Sensor Input Type; Calibration (Diode/Platinum Input) - Lakeshore 330 User Manual

Lake Shore Model 330 Autotuning Temperature Controller User's Manual
5.9

CHANGING SENSOR INPUT TYPE

The factory establishes sensor input type and model number before shipping. Configure sensor input type by
setting DIP switches S1 and S2 on the main controller PCB. To change the DIP Switch settings, follow the
REMOVE COVER procedure in Paragraph 5.6 and see the Table 5-1 DIP switch settings. Switch diodes and
resistor sensors in the field with no recalibration. Diode/Resistor sensors and thermocouple sensors cannot be
exchanged. After changing the DIP switches, follow the REPLACE COVER procedure in Paragraph 5.6.

5.10 CALIBRATION (DIODE/PLATINUM INPUT)

To calibrate the controller, you will need the following:
• Digital Multimeter (DMM) with a 4½-digit display and capable of 4-lead resistance measurement.
• Test connector wired as follows:
This is the connection for a resistive sensor. R
possible (20-50 ppm/°C).
WARNING: To avoid potentially lethal shocks, refer procedure below to qualified personnel.
1. Follow the REMOVE TOP procedure in Paragraph 5.6.
2. Select the PT input switch for both inputs A and B. See Table 5-1.
3. Turn off the heater.
4. Allow the controller to warm up for 1 hour.
5. Measure and note resistance of the R
6. Put the test connector in Channel A and attach the multimeter (in DC Voltage mode) across R
7. Adjust Channel A current source with trim potentiometer R21 until current through R
example, for a 1000.0 Ω resistor, the voltage should read 1.0000 V. For a 1002.5 Ω resistor, the voltage
should read 1.0025 V.
8. Repeat steps 6 and 7 for Channel B, except adjust R25.
9. Connect the negative lead of the multimeter to TP1 and the positive lead to TP2.
10. Adjust R10 until the voltage reads +2.5000 VDC.
11. Place the test connector back on Channel A.
12. Short across R for Zero Calibration.
TEST
13. Configure the Model 330 to display Channel A in ohms (Ω).
14. Adjust R6 until the display reads 0.000 Ω (toggles to error).
15. Repeat Steps 11 – 14 for Channel B, except adjust R8.
16. Power off the Model 330.
17. Disconnect the test connector.
18. Switch the input back to the desired sensor type.
19. Follow the REPLACE TOP procedure in Paragraph 5.6.
Service & Calibration
3 (+I)
4 (+V)
2 (­V)
1 (­I)
should be nominal 1000 Ω with temperature as stable as
TEST
connector to 4½ places with a 4-lead measurement.
TEST
R
TEST
1000 9
is 1 mA. For
TEST
.
TEST
5-7