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2620A, 2625A
Users Manual
6-14
RTD Temperature Accuracy Test
The following two RTD Temperature Accuracy Tests are different in that one uses a
Decade Resistance Source and the other uses an RTD. Only one of the tests need to be
performed to assure operation.
RTD Temperature Accuracy Test (Using Decade Resistance Source)
Assure Channel 0’s Accuracy Verification Test for DC Volts and 300 Ohm Resistance
Range meets minimum acceptable levels.
1. Switch OFF power to the instrument and disconnect all high voltage inputs.
2. Remove the Input Module from the rear of the instrument. Open the Input Module
and connect a pair of test leads (keep as short as possible) to the H (high) and L
(low) terminals of channel 1. For 4-terminal performance testing, connect a second
pair of test leads to the H (high) and L (low) terminals of channel 11. Install the
Input Module back into the instrument.
3. Connect channel 1’s test leads to the Output HI and LO terminals of the Decade
Resistance Source. For 4-terminal performance testing, also connect channel 11’s
test leads to the Output HI and LO terminals of the Decade Resistance Source.
Connect as shown in Figure 6-3.
Note
4-terminal connections are made using pairs of channels. 4-terminal
measurements can only be made on channels 1 through 10. The
accompanying pairs are channels 11 through 20.
4. Switch the instrument ON.
5. Select the 4-terminal RTD temperature function, RTD type PT, for channel 1 on the
Hydra Series II Instrument. Press MON and ensure the display reads between the
minimum and maximum values shown on Table 6-5.
6. The RTD Temperature Accuracy test is complete. However if you desire to perform
this test on Input Module channels (2 through 10) repeat steps 1 through 5
substituting in the appropriate channel number.
Note
The only type of temperature measurement that can be made on channel 0
is 2-terminal RTD. Channels 11 through 20 will support only 2-terminal
RTD’s.
Table 6-5. Performance Tests for RTD Temperature Function (Resistance)
(DIN/IEC 751 Amendment 1) (IPTS-68)
DECADE RESISTANCE
SOURCE
TEMPERATURE SIMULATED
°C
TEMPERATURE ACCURACY
1 YEAR @ 18-28°C
100 e 0 ± 0.12°C
200 e 266.42 ± 0.22°C
300 e 558.00 ± 0.37°C
These figures assume that RTD R0 is set to 100.00 ohms for each channel.
Accuracy given is for 4-wire measurements only. For 2-wire measurements, degrade the accuracy
specifications by 5.2 °C per ohm of single lead wire resistance. For 2-wire measurements, degrade the
accuracy by an additional 11°C (channels 1 .. 20) or 0.05°C (channel 0).