Emerson ROC827 - Manual (Page 121)

ROC827 Instruction Manual
Issued Mar-06 Troubleshooting 6-9
3. Measure the resistance across terminals + and –. A reading of 0 (zero)
ohms should be obtained. No continuity should be indicated.
4. Measure the resistance across the terminals + and –. The reading
should indicate an open circuit.
6.3.8 Troubleshooting Pulse Input Modules
Equipment Required:
ƒ Pulse Generator
ƒ Voltage Generator
ƒ Frequency Counter
ƒ Jumper wire
ƒ 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 verify high-speed operation:
1. Disconnect the field wiring at the PI module terminations.
2. Connect to ROCLINK 800 software.
3. Select Configuration > I/O > PI Points.
4. Select the correct Pulse Input Point Number.
5. Connect a pulse generator having sufficient output to drive the
module to terminals L+ or H+ and COM. The pulse generator must
synthesize a square wave signal of 50% for every cycle.
6. Connect a frequency counter across terminals L+ or H+ and COM.
7. Set the pulse generator to a value equal to, or less than 10 KHz.
8. Set the frequency counter to count pulses.
9. Verify, using ROCLINK 800 software, that the count read by the
counter and the ROC827 are the same.
10. Remove the test equipment, and reconnect the field device.
6.3.9 Troubleshooting RTD Input Modules
The RTD module is similar in operation to an Analog Input module and
uses the same troubleshooting and repair procedures.
Equipment Required :
ƒ Multimeter
ƒ PC running ROCLINK 800 software