System Operation

Tle power

• Module operation

• Error (module error and channel error)

Cycle Power

When you cycle the module’s power, the RTD module checks its

internal circuits, memory, and basic functions via hardware and

software diagnostics. During this time the module status LED indicator

remains off. If no faults are found during the diagnostics, the module

status LED indicator is on.

After the checks are complete, the RTD module waits for valid

channel configuration data from your SLC ladder logic program

(channel status LED indicators off). After configuration data is written

to one or more channel configuration words and their channel enable

bits are set by the user program, the channel status LED indicators go

on and the module continuously converts the RTD or resistance input

to a value within the range you selected for the enabled channels. The

module is now operating in its normal state.

Each time a channel is read by the module, that data value is tested by

the module for a fault condition, for example, open circuit, short

circuit, over range, and under range. If such a condition is detected, a

unique bit is set in the channel status word and the channel status

LED indicator blinks, indicating a channel error condition.