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16
Troubleshooting
In case you run into difficulty while operating the 1560 system, this section
provides some suggestions that may help you solve the problem. Below are
several situations that may arise followed by possible causes of the problem
and suggested actions you might take.
16.1
Incorrect Temperature Reading
While attempting to measure temperature the display shows an incorrect value
or no value at all (". . . . . . . . . . ").
If the temperature readings seem to be incorrect you should first check to see if
the resistance, or voltage in the case of thermocouples, is being measured cor-
rectly. Set up the display to show the resistance or voltage (INPUT) for the
channel (see Section 5.3.1.2). If the resistance or voltage is incorrect refer to
the next subsection for troubleshooting incorrect resistance or voltage readings.
If the resistance or voltage is being measured correctly but the displayed tem-
perature value is incorrect consider the following possibilities:
• One or more coefficients are incorrect. This is a common mistake.
While entering coefficients it is easy to miss a digit or sign. Check all the
values carefully using the EDIT PROBE function (see Section 5.2.1)
comparing them with the values on the calibration certificate for the
probe. Use the TEST CONV function to test the coefficients (see Section
5.2.3).
• The selected conversion type is incorrect. Check to make sure the cor-
rect conversion type is selected. In the case of thermocouples, make sure
you have selected the correct thermocouple type. Again, you can use the
TEST CONV function to test the temperature conversion calculation.
• The measurement is out of range. The 1560 may not be able to calcu-
late temperature accurately if the resistance or voltage is outside the valid
range. The measured resistance or voltage may be too low or too high if
the actual temperature is too low or too high or if there is a problem with
the sensor (see below).
16.2
Incorrect Resistance or Voltage Reading
While attempting to measure resistance or voltage the display shows an incor-
rect value or no value at all (". . . . . . . . . . ").
Consider the following possibilities:
• Poor or incorrect connection of the probe. A common mistake is to
connect the wires of the probe to the wrong terminals. Check the wiring
carefully, especially when using a four-wire PRT (see Figure 13 on page
114 or Figure 15 on page 126). Make sure the lead wires are fastened
down tightly.
16 Troubleshooting
Incorrect Temperature Reading
179
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