Filter
Top Products
HYDRA
Service Manual
4-12
7. 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 support only 2-terminal RTDs.
Table 4-5. Performance Tests for RTD Temperature Function (Resistance Source)
Decade Reisitance
Simulated °C Temperature
Temperature Accuracy Specifications
Source
2620A/2635A* 2635A*
1 Year @ 18-28°C
100Ω
200Ω
300Ω
0
266.58
558.00
0
266.34
557.70
±0.24°C
±0.48°C
±0.75°C
* RTD temperature linearizations changed between the 2620A/2625A and 2635A Hydra instrument
firmware. The 2620A & 2625A Hydra instruments are based on the International Practical Temperature
Scale of 1968 (IPTS-68). The 2635A Hydra Instrument is based on the International Temperature Scale
of 1990 (ITS-90).
These figures assume that RTD R0 is set to 100.00Ω for each channel.
Accuracy given is for 4-wire measurements only.
4-12. RTD Temperature Accuracy Test (Using DIN/IEC 751).
1. Switch OFF power to the instrument and disconnect all other high voltage inputs.
2. Remove the Input Module from the rear of the instrument. Open the Input Module
and connect a Platinum RTD, conforming to the European Standards IEC 751 (DIN
43760).
2-terminal RTD: Connect the RTD excitation leads to the H (high) and L (low)
terminals of channel 1.
4-terminal RTD: Connect the RTD excitation leads (one red and one black wire) to
the H (high) and L (low) terminals of channel 11. Connect the second pair of RTD
red and black leads to the H and L leads of channel 1. (Refer to Figures 4-1 and 4-2
for proper connection.) Reinstall the Input Module into the instrument.
Note
4-terminal connections are made using pairs of channels. 4-terminal
measurements can only be made on channels 1 through 10. Their
accompanying pairs are channels 11 through 20.
3. Switch the instrument ON.
4. Insert the RTD probe and a mercury thermometer in a room temperature bath. Allow
20 minutes for thermal stabilization.
5. Depending on the type of connection made in step 2, select either the 2-Terminal or
4-Terminal RTD temperature function, RTD type PT (DIN IEC 751), for channel 1
on Hydra. Press MON and ensure the display reads the temperature of the room
temperature bath (within tolerances shown in Table 4-6) as measured by the mercury
thermometer.