Rockwell Automation T8433 Trusted TMR Isolated 4-20 mA Analogue Input Module - 20 Channel - Manual (Page 28)

Trusted
TM
Module T8433
Issue 11 Apr 10 PD-T8433 28
4.3. I/O Status LEDs
There are 20 input channel status LEDs on the module front panel, one for each field input. These
indicators are controlled by the FPU. The FPU receives data from each of the module slices. The
FPU performs a 2-oo-3 vote on each data bit from the slices and sets the indicators accordingly.
The input status LED mode is dependent upon the voltage level of the field I/O signal. Each field input
voltage is measured and compared to six threshold levels (four configurable and two fixed) which
produce seven threshold bands. Each threshold band can be defined to have a particular indicator
mode: off, green, red, flashing green, or flashing red.
The configurable voltage thresholds and LED modes allow users to customise the input measurement
and status indications to suit individual application requirements. Without customisation, the default
indicator modes are suitable for analogue inputs as described below:
INDICATOR STATE DESCRIPTION
Off ’Normal’ (states 1,2,3)
Green - steady ‘High alarm’ (states 4,5)
Green – flashing Overrange (state 6)
Red – flashing Underrange (state 0) or Channel Fault (8 to 15)
Table 18 Default I/O Status Indicators
Note: The LEDs indicating channel status may be configured to suit user requirements by
implementing the procedure for configuring the System.INI file detailed in PD-8082B.