Setup And Calibration; Equipment Needed; Voltage Regulator Adjustment - Wahl Heat-Prober 392AHP User Manual

Platinum-rtd thermometers

Table of Contents

Heat-Prober

6.0

SET-UP AND CALIBRATION

A. Digital voltmeter, Fluke 41/2 digit Model 8600A or equivalent.

B. Wahl Platinum Calibrator (Model Number CAL392HT or CAL392LT) or General Radio

decade box, Model

1433-1 (or equivalent) with standard coil cord (Model 10434-01 or 10434-02) cable as used with

Wahl probes.

C. Power supply — Powermate, Model OPA-1OC or equivalent.

6.2 Voltage Regulator Adjustment (Note: Meters with serial numbers S/N 3445 and higher, or

N Series do not require adjustment of voltage regulator.)

Remove the 4 screws from the bottom of the case, then remove the top cover. You will note the

adjustment points as shown in Figure 6-1.

1. Initially the 392M should be set-up with an external power supply (rather than a

battery) so that the current can be limited to no more than 120 milliamperes.

2. Connect the plus (+) DVM lead to C-10 junction common with Q2.

Connect the minus (-) lead to the cathode lead of CR1.

3. Apply power to the 392M using an external power supply with the voltage set at 6.5V

and current limit set at 120 milliamperes. Connect power supply (+) to U1-1 and (-) to CR1 -

cathode. Adjust R21 for voltage reading of exactly +5.000 volts on the DVM.

4. When the 392M has been mounted in its case and connected to a 5-battery pack, the

DVM is connected as described above and the +5.000 adjustment checked and trimmed if

necessary.

Platinum-RTD Thermometers User Manual

Table of Contents