GE GFK-0787B Fault, No Fault, and Alarm Contacts, Discrete Input Fault Contacts for GMR

5

Fault, No Fault, and Alarm Contacts

Fault and No Fault contacts can optionally be used to detect fault or lack of fault conditions on a discrete (%I or %Q) or analog (%AI or %AQ) reference. They can also be programmed with the Series 90-70's built-in fault-locating references. In a GMR system, there are fault contacts associated with voted inputs, with the original block inputs, and with logical outputs. Alarm contacts can also be used to detect high or low alarm conditions on an analog (%AI or %AQ) reference. See the Programming chapter for information about using these contacts.

Discrete Input Fault Contacts for GMR

In the discrete Input Table there are fault contacts associated with each item of voted input data, non-voted input data, and ªrawº data input from bus A, B, and C:

Discrete Input Table

Input	Voted Inputs
Voting
Logic
	Non-voted Inputs
Bus A inputs	A
Bus B inputs	B
Bus C inputs	C
	Reserved inputs

Conditions that Cause these Fault Contacts to be Set

•Any fault

(see text below)

•Genius fault

•Autotest fault

•Genius fault

•Autotest fault

•Discrepancy fault

•Genius fault

•Autotest fault

•Discrepancy fault

•Genius fault

•Autotest fault

•Discrepancy fault

•Genius fault

Conditions that Cause Discrete Input Fault Contacts to be Set

For more information about fault contacts, see page 7-21.

HFor the voted input, a fault contact is set if any of the physical inputs has an associated fault contact set. For example, if a there is an autotest fault on input A, a fault contact is set both for input A and for the voted input.

HFor non-voted inputs, the single fault contact is associated with the physical input. It is set under the following conditions:

h Autotestfault. Set on digital inputs configured for autotesting, if autotesting detects a fault.

h Geniusfaults, including Loss of Block.

h Line fault. These are a feature of the 16-circuit DC blocks. To report line faults, an input must be configured for tristate operation.

For blocks in GMR mode, a line fault represents a short circuit fault on the field wiring.

For non-GMR blocks, a line fault represents an open circuit fault in the field wiring.

HFor bus A, bus B, and bus C inputs, fault contacts are set under the following conditions:

h Autotestfault(see above). h Line fault (see above).

h Geniusfaults, including Loss of Block.

h Discrepancy between the raw input data, and the corresponding voted input.

GFK-0787B Chapter 5 Diagnostics 5-25