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ROC827 Instruction Manual
Issued Mar-06 Troubleshooting 6-10
Caution
Failure to exercise proper electrostatic discharge precautions, such as
wearing a grounded wrist strap may reset the processor or damage
electronic components, resulting in interrupted operations.
1. Disconnect the field wiring at the RTD module terminations.
2. Connect to the ROCLINK 800 software.
3. Select Configuration > I/O > RTD Point.
4. Select the correct RTD Point Number.
5. If any of the input wires are broken or not connected, the ROCLINK
800 software indicates the Raw A/D Input value is either at minimum
(less than 47974) or maximum (greater than or equal to 61958) as
follows:
An open at terminal + gives a maximum reading.
An open at terminal – gives a minimum reading.
An open at terminal RET gives a minimum reading.
To verify the operation of the RTD module:
6. Connect to the ROCLINK 800 software.
7. Select Configuration > I/O > RTD Point.
8. Disconnect the RTD and connect a jumper between terminals – and
RET of the RTD module.
9. Connect either an accurate resistor or decade resistance box with a
value to give a low end reading across terminals + and –.
Note: Use the temperature-to-resistance conversion chart to determine
the resistance value required for the type of RTD being used.
10. Verify that the Raw A/D Input value changed and reflects the
Adjusted A/D 0% value.
11. Change the resistance to reflect a high temperature as determined by
the temperature-to-resistance conversion chart.
12. Verify that the Raw A/D Input value changed and reflects the
Adjusted A/D 100% value.
13. Remove the test equipment, and reconnect the field device.
6.3.10 Troubleshooting J and K Type Thermocouple Input Modules
Many digital multimeters can generate and measure thermocouple (T/C)
signals. Check your multimeter’s product documentation to see if it
supports thermocouples and how to correctly use the feature if so
equipped. You may require an optional T/C adaptor to use the multimeter.
To test a thermocouple, do not parallel the voltage meter on a
thermocouple that is connected to a ROC827, as it will distort the signal.