GE GFK-0787B user manual Analog Fault and Alarm Contacts for GMR, Fault Contacts for Analog Inputs

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Analog Fault and Alarm Contacts for GMR

The fault, high alarm and low alarm contacts of non-voted analog inputs and outputs are not affected by GMR analog I/O processing.

Fault Contacts for Analog Inputs

As with discrete inputs, voted analog inputs have fault contacts associated with both the raw data inputs and the corresponding voted inputs. Non-voted analog inputs also have associated fault contacts. (For more information about fault contacts, see page 7-21.)

Input

Voting

Logic

Bus A inputs

Bus B inputs

Bus C inputs

Analog Input Table

Voted Inputs

Non-voted Inputs

A

B

C

Conditions that Cause these Fault Contacts to be Set

•Any fault (below)

•Genius fault

•Genius fault

•Discrepancy fault

•Genius fault

•Discrepancy fault

•Genius fault

•Discrepancy fault

HGenius faults include Loss of Block, plus the following:

h Underrange: the input exceeds ±32,767 engineering units or ±4095 counts. The

block transmits an underrange message and sets the value to its minimum.

h Overrange: the input exceeds +32,767 engineering units or +4095 counts. The

block transmits an overrange message and sets the value to its maximum.

h Openwire: Used only for 4±20mA inputs. The fault contact is set if the input current falls below 2mA. Note that a 4 to 20 mA signal to two or more blocks must be converted to a voltage, in which case Open Wire faults are not detected.

h Wiring error

h Internal channel fault: an internal channel fault, such as the failure of the A/D converter. Block output is indeterminate.

h Channelshorted: For RTD blocks only. Block output is indeterminate.

HDiscrepancyfault: the A, B, or C input is subject to voting and is outside the discrepancy range.

Fault Contacts for Analog Outputs

For analog outputs, a fault contact is set for any Genius fault, including Loss of Block.

Alarm Contacts

For analog data, there are two additional types of diagnostic contacts that can be used in the application program, the High Alarm and Low Alarm contacts. These contacts indicate when an analog reference has reached one of its alarm limits. Alarm contacts are not considered to be fault contacts.

Alarm contacts can be used on a separate bus in a GMR system, but they can not be used on any parts of the system that are included in the GMR configuration.

5-28	GeniustModular Redundancy Flexible Triple Modular Redundant (TMR) System	GFK-0787B
	User's Manual ±March 1995