Emerson ROC827 instruction manual Checklists, Serial Communications, 2 I/O Point

ROC827 Instruction Manual

6.2Checklists

If the LEDs do not display:

ƒBy default, LEDs on the communication modules and I/O modules enter Sleep mode after five minutes.

ƒTo turn the LEDs on, press the LED button located on the CPU for one second.

Note: Using the ROCKLINK 800 software, you can disable this feature so that the LEDs always remain on.

6.2.1 Serial Communications

If you are experiencing troubles with a serial communications connection (LOI, EIA-232, EIA-422, or EIA-485):

ƒCheck to make sure power is applied to the ROC827 unit. Check the ON/OFF jumper, the wiring connections at CHG+ and CHG–, and the wiring at the power source.

ƒCheck the wiring to the termination block or connector. Refer to Chapter 5, Communications.

ƒCheck the communication port settings using ROCLINK 800 Configuration software. Refer to ROCLINK 800 Configuration Software User Manual (Form A6121).

6.2.2 I/O Point

If you are experiencing troubles with an I/O point (Analog Input, Analog

Output, Discrete Input, Discrete Output, Pulse Input, RTD Input, or

Thermocouple Input):

ƒCheck (using ROCLINK 800 software) to see how the channel is configured.

ƒIf the configuration looks correct, then follow the procedure for troubleshooting that type of I/O (refer to Chapter 6, sections 3 through 10).

ƒIf a module does not function correctly, determine if the problem is with the field device or the module.

ƒCheck a module suspected of being faulty for a short circuit between its input or output terminals. If a terminal not directly connected to ground reads 0 (zero) when measured with an ohmmeter, the module is defective and must be replaced.

Note: Return faulty modules to your local sales representative for repair or replacement.

Issued Mar-06 Troubleshooting 6-2