Fluke 2180A - Manual (Page 36)

2180A
3. Toggle the RTD select switch for setting 9. Tog­
gle S3 to manual position.
4. On the 2180A front panel, access calibration
adjustments behind the cover in the lower left
corner. Loosen the screw and slide the cover to the
left.
5. Set the calibrator output to 0.00102V and divider
to +100 (10.2//V to 2180A). Note the 2180A reading.
Now reverse the input polarity and again note the
reading. Adjust R29 (access beneath front panel cali­
bration cover-ZERO) until the readings in both
directions are the same.
6. Adjust R14 (Main PCB) for a reading of +10.
Reverse input polarity and look for a 2180A reading
of -10. Repeat steps 4 and 5 if a reading of -10 is not
obtained.
4-33. Resolution Adjustments
4-34. Use the following procedure to adjust the 2180A’s
.01 ° and. 1 ° display and the verify autoranging operation.
1. Replace the 2180A’s top cover. Leave test
equipment connected (DC Voltage Calibrator,
Voltage Divider) as described in Zero Adjust
instructions.
2. On the 2180A front panel, access calibration
adjustments by loosening the screw and sliding the
cover to the left.
3. On the RTD Input Module, set S2 to AUTO.
Set input switch SI to setting 9 (CAL).
4. Set the DC Voltage Calibrator output to 9.9V
(99 mV to the 2180A).
5. Adjust R27 (.01° cal potentiometer) for a
reading of 99000 ±1.
6. Change the calibrator output to 4.5V (45 mV to
2180A). The 2180A should read 45000 ±2.
7. Set switch S2 out of AUTO. Set DC calibrator
output to 9.9V and the divider to 10 (990 mV to
2180A).
8. Adjust R28 (.1°C cal potentiometer) for a read­
ing of 99000 + 1.
9. Change the calibrator output to 4.5V, the 2180A
should read 45000 ±2 (450 mV to 2180A).
10. Place S2 in the AUTO position.
4-35. RTD Input Module Adjustment
4-36. Use the following procedure whenever 2180A
calibration or repair has been accomplished or when a
different RTD probe is installed.
1. Connect the RTD probe to the RTD Input
Module (TBl).
2. Select the applicable input switch setting (SI)
and insert the probe into a ice bath. Refer to the fol­
lowing paragraph for a suggested method of con­
structing a ice bath.
3. Install the RTD Input Module in the 2180A.
Apply power to the 2180A.
4. Adjust R2 (access through the rear hole on RTD
Input Module) until the 2180A displays the ice bath
temperature.
5. Calibration of the 2180A is now complete.
Disconnect all test equipment from the instrument.
4-37. Ice Bath Construction
4-37. Ice Bath Construction
4-38. The following instructions provide a recommended
method of constructing a ice bath:
NOTE
Distilled water must be used to make the ice
and must also be used in the ice bath.
1. Required material; supply of ice, distilled water,
and an insulated jar with an unbreakable lid (thermos
or equivalent).
2. Prepare the insulated jar by drilling one or more
holes just large enough to accept the RTD Probe or
Probes.
3. Fill the insulated jar with shaved or crushed ice.
4. Fill the insulated jar with enough distilled water
so that the ice becomes slush but not enough to float
the ice.
NOTE
As the ice melts, siphon off the excess water and
add more ice. Allow about 5 to 10 minutes for
the water to drop back to the freezing point.
4-6