Gain Adjustment Procedure For The Mh 60 - Chauvin Arnoux MH 60 Manual De Instrucciones

7.2. GAIN ADJUSTMENT PROCEDURE FOR THE MH 60

Make sure you are technically qualified to perform this operation.
Warning: Make this adjustment only if the gain coefficient is manifestly outside tolerances. Check
first that nothing interferes with the movements of the jaws and that the air gap is clean. Make
sure that the clamp is adequately charged. Disconnect the USB charger.
„ Check of the gain:
Equipment necessary: AC current calibrator accurate to 0.1 % capable of delivering least 3 A at
50/60 Hz, 10-turn coil, RMS AC multimeter accurate to better than 0.1 %, female BNC/male banana
adapter, leads.
Step Action
Switch the clamp on and clamp it centred on the coil. Connect the clamp to the
1
multimeter using the adapter.
2 Optional: Demagnetize the clamp (0 ... 3 A ... 0 / 50 or 60 Hz)
Adjust the DC-Zero with no current and do not subsequently move the clamp.
3
The measurement must be < 0.1 mV DC.
4 Establish a current of 3 A
5
Measure the output voltage with the multimeter set to AC rms and note this value.
- If 295.1 mV ≤ Reading ≤ 304.9 mV → Do not adjust.
- Otherwise: adjust the gain.
„ Adjusting the gain:
Step Action
1 Switch the clamp on and clamp it centred on the coil.
2
Optional: Demagnetize the clamp (0 ... 3 A ... 0 / 50 or 60 Hz)
3 Adjust the DC-Zero with no current and do not subsequently move the clamp.
Press the DC-Zero key and the ON/OFF key for approx. 30 s, until all of indicators
4
blink. At this point, there is no turning back: the procedure must be completed.
5 Release the keys. The BAT and ON/OFF LEDs blink.
6
Establish a current of
Adjust the output by successive presses
7
± 1.5 mV. Wait for the display to stabilize between presses.
8 Press the ON/OFF key 2 s (the ON/OFF LED blinks) to store the gain.
9 Gradually reduce the current from 3 A to zero.
10
Check the gain as before.
(1) Gradually increase the current starting from zero.
(2) Gradually increase the current, starting from zero, up to 3 A, then gradually reduce it to zero.
(3) The increment is approximately 0.5 mV.
60 Hz in the coil.
1
3 A 60 Hz in the coil.
1
3
32
2
on the DC-Zero key until you reach 300 mV
.
2
.