Allen-Bradley 1794-IE8H User Manual download pdf (Page 22)

Publication 1794-UM063A-EN-P - March 2006

1-6 About the FLEX I/O HART Analog Modules

Programming the Remote Fault Alarm

For the remote fault alarm, you must program the threshold in 0.1 mA steps at

any level on the high or low end of input signal range. The remote fault alarm

activates if your I/O module receives input signal values of:

• 100.63 to 111.88% (20.1 to 21.9 mA) on the high end of input

signal range

• -0.63 to -11.88% (3.9 to 2.1 mA) on the low end of input

signal range

Local Fault Alarm

The local fault alarm notifies you when the loop to the transmitter or field

device, if no transmitter is used, is open or shorted.

• 112.50% (22 mA) or higher on the high end of input signal range.

This value indicates a short in the loop.

• -12.50% (2 mA) or lower on the low end of input signal range.

This value indicates an open wire condition in the loop.

The remote fault and local fault alarms are issued with the same bit whether

the cause is an under or overrange. Monitor the overrange and underrange bits

in your programming software to determine if the problem is a high current or

low current.

IMPORTANT

This alarm is only active for one band, either on the high side of normal

operation or the low side.The Remote Transmitter Error Up/Down parameter

determines which side is active. See page 2-2 for a description of the

Remote Transmitter Error Up/Down feature.

IMPORTANT

Once the alarm is issued, it remains active as long as the input

signal value remains in the programmed range.

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Allen-Bradley 1794-IE8H User Manual Page 22