Fluke 2180A - Manual (Page 34)

2180A
Table 4-2. Recommended Test Equipment
TEST EQUIPMENT
MINIMUM USE
SPECIFICATIONS
RECOMMENDED
MODEL
Variable Line-Voltage
Transformer
100,120, 220, 240V ac, as required,
±10%
General Radio VARIAC W5HM
Decade Resistance Box .01Ì2 resolution General Radio 1433T,
ESI Model RS925A, or
equivalent
Voltage Divider 100:1 Fluke Y2022 or equivalent
Calibrator (DC Source) 10 m V resolution Fluke 343A or equivalent
Digital Voltmeter (±100 m V) 100 m V resolution, on 10V range Fluke 8800A or equivalent
Lag Bath Temperature Stable, .01° resolution Customer Constructed. (See Lag
Bath Construction, this section)
4-23. CALIBRATION
4-24. The thermometer should be calibrated at either
90-day or annual periods, depending upon the accuracy
desired, and any time that repairs are made to the
instrument. Conversion between Fahrenheit and Celsius
scales is realized through a mathematical computation by
the microcomputer. Calibration in °F is recommended.
Calibration in either scale (° F or °C) insures the accuracy
of the other. Either scale can be verified by executing the
Performance Test.
4-25. Equipment Preparation
4-26. Prepare the equipment for calibration using the
following procedure:
1. Remove the top cover from the instrument.
2. Apply power to 2180A and all test equipment to
be used. Insure the 2180A warm-up period has been
sufficient to reach rated accuracy (at least 20 minutes).
3. Select the desired temperature scale (°C or °F).
If the Limits Option is installed select the LIMITS
or >) function.
NOTE
Before removing the RTD Input Module,
power switch to OFF.
set
CAUTION
Do not connect analog common (OV) to digital
common (-15V with respect to analog
common). Instrument damage may result.
4-27. Reference Adjust
4-28. Perform Reference Adjust using the following
procedure:
1. Connect the DVM between TP 16 and TPl
(Analog Common).
2. Adjust R7 for a reading of 6.2V ±100 pN.
4-29. Reference Adjust (+V)
4-30. Perform the Reference Adjust for the ±V using
the following procedure:
1. Connect the DVM to TP 17 (HI) and TPl (LO -
Analog Common).
2. Adjust R44 to obtain a reading of 6.2V ±100
m V.
4-31. Zero Adjust
4-32. Perform the Zero Adjust using the following
procedure:
1. Connect the 2180A Digital Thermometer, DC
Voltage Calibrator, and Voltage Divider as
illustrated in Figure 4-3.
2. On the RTD Input Module, place a jumper
between -V and -S on TBl. Select AUTO (S2 on
the Input PCB).
4-4