Fluke 5520A Operator's Manual page 122

5520A
Operators Manual
Note: The "u" indicator that occasionally appears in the Output Display indicates an
internal adjustment to the measured isothermal block temperature and is normal. If it
appears for more than 10 seconds (nominal), or if it appears to flash continuously, check
to see that you are not externally heating the thermocouple miniconnector or wires.
4-33. Setting Temperature Simulation (RTD)
RTDs have a characteristic resistance at specific temperatures. The simulated output,
then, is a resistance value based on the selected temperature and type of RTD being
simulated. To toggle the degree reference between the 1968 International Provisional
Temperature Standard (ipts-68) and the 1990 International Temperature Standard
(its-90), see "Using the Instrument Setup Menu" earlier in this chapter.
Complete the following procedure to set a simulated RTD temperature output at the
5520A front panel NORMAL terminals. If you make an entry error, press Gto clear
the display, then reenter the value.
1. Press R to clear any output from the 5520A.
2. Connect the UUT as described earlier in this chapter under "Connecting the
When calibrating Resistance Temperature Detectors (RTDs) using the
three-terminal connection shown in Figure 4-9, be sure the test leads have
identical resistances to cancel any errors due to lead resistance. This can
be accomplished, for example, by using three identical test lead lengths
and identical connector styles.
3. Set the UUT to measure temperature on the desired range.
4. Press the numeric keys and decimal point key to enter the desired temperature output
5. For an output in °C, press the C key. For °F, press b and then the C key.
4-42
alloy wires and you are using the isothermal block internal to the 5520A
Calibrator. Select extrnl when using an external isothermal block, and when the
selected thermocouple has copper wires. Press the REF softkey to enter the value
of the external temperature reference. The best accuracy is obtained when you
use extrnl and the external isothermal block is maintained at 0 °C.
•
REF (Temperature Reference) Displays the value of the temperature reference.
When the Reference Source is Internal, the display shows the internal reference,
or NONE if the 5520A is in Standby. When the Reference Source is External,
the display shows the value you entered for external reference.
•
OUTPUT (Temperature Output Device) Selects the temperature device:
thermocouple (tc) or resistance temperature detector (rtd). Select tc.
•
TYPE (Thermocouple Type) Selects the thermocouple type simulated by the
5520A Calibrator. The default is type K. (The 10 µV/°C and 1 mV/°C settings
are used as an accurate output voltage source for user-supplied linearizations.)
Calibrator to a UUT."
(maximum 6 numeric keys). For example, 123.456.
Note