Emerson ROC827 - Manual (Page 114)

ROC827 Instruction Manual
Issued Mar-06 Troubleshooting 6-2
6.2 Checklists
If the LEDs do not display:
ƒ By default, LEDs on the communication modules and I/O modules
enter Sleep mode after five minutes.
ƒ To 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):
ƒ Check 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.
ƒ Check the wiring to the termination block or connector. Refer to
Chapter 5, Communications.
ƒ Check 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):
ƒ Check (using ROCLINK 800 software) to see how the channel is
configured.
ƒ If the configuration looks correct, then follow the procedure for
troubleshooting that type of I/O (refer to Chapter 6, sections 3 through
10).
ƒ If a module does not function correctly, determine if the problem is
with the field device or the module.
ƒ Check 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.