Emerson ROC827 Network Card User Manual


 
ROC827 Instruction Manual
Issued Mar-06 Troubleshooting 6-11
Do not try to verify a thermocouple that is connected and actively being
monitored by a ROC827 by measuring the voltage at the ROC827
terminal blocks.
It is suggested that you independently verify the process temperature, by
using a certified thermometer in an adjacent thermowell, and then
compare it to what the ROC827 is reading.
Equipment Required:
Multimeter
PC running ROCLINK 800 software
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.
To test the thermocouple module:
1. Disconnect the thermocouple from the thermocouple module.
2. Generate the correct J or K signal using a multimeter and connect the
wiring from the multimeter to the T/C module in the ROC827.
3. Verify the ROC is reading the generated temperature form the
multimeter.
4. Remove the test equipment, and reconnect the field device.
To test the thermocouple:
1. Disconnect the thermocouple from the ROC827.
2. Connect the thermocouple directly to the multimeter and verify the
reading is correct by comparing it to a certified temperature
measurement device connected to the process temperature the T/C is
measuring.
3. Remove the test equipment, and reconnect the field device.
Unintentional thermocouple junctions cause many measurement errors.
Remember that any junction of two different metals will cause a junction.
To increase the length of the leads from the thermocouple, use the correct
type of thermocouple extension wire. Any connector must be made of the
correct thermocouple material and correct polarity must be observed.
If the reading is off:
1. The type J or K thermocouples are selected on a per channel basis on
the thermocouple module. Verify each channel on the ROC827 and
make sure it is set for the type of thermocouple that you are using.
2. Ensure any plugs, sockets, or terminal blocks used to connect the
extension wire are made from the same metals as the thermocouples
and correct polarity is observed.
3. Verify all connections are tight.