Honeywell Midas User Manual page 96

Table 10-5. Fault Relay Configuration options
LCD
Description
Symbol
1FLt Instrument fault only
2FLt Separate fault relays
CmbF Combined fault relay
nEtr Network remote mode
Once the relays are configured for network remote
mode, they will respond to updates to the three
associated NVIs. The values ST_LOW, ST_MED,
ST_HIGH and ST_ON will cause the relays to
energize. The value ST_OFF will cause the relays
to de-energize. The configuration settings for
"normally energized" and "normally de-energized"
have no effect if the relays are in network remote
mode. However, the relays can still be configured
for normally open or normally closed contacts by
moving the jumpers on the Midas
Caution
Several failure modes will cause the relays
to de-energize. These modes include power
failures and CPU lockups. Furthermore,
power must be removed from the Midas
certain maintenance procedures. External
equipment should be designed to prevent
creation of expensive or dangerous conditions
when the relays de-energize. For applications
requiring a highly-reliable digital output,
Honeywell Analytics recommends purchasing
a dedicated DO device.
nviReset
This network variable input causes alarms and
faults to be reset when it is updated with ST_LOW,
ST_MED, ST_HIGH or ST_ON.
Source of Signal for Relays
Relay 1 Relay 2 Relay 3
Alarm 1 Alarm 2 Inst Fault
Any Alarm Maint Fault Inst Fault
Alarm 2 Alarm 2 Any Fault
nviRelay1 nviRelay2 nviRelay3
backplane PCB.
®
for
®
Midas
nviRequest
Updates to this NVI have the effects listed in Table
10-6. These requests are usually sent by the
network management tool.
Table 10-6. Request Implementation
Request
0 RQ_NORMAL
1 RQ_DISABLED
2 RQ_UPDATE_STATUS
3 RQ_SELF_TEST
4 RQ_UPDATE_ALARM
5 RQ_REPORT_MASK
6 RQ_OVERRIDE
7 RQ_ENABLE
8 RQ_RMV_OVERRIDE
9 RQ_CLEAR_STATUS
10 RQ_CLEAR_ALARM
11 RQ_ALARM_NOTIFY_
ENABLE
12 RQ_ALARM_NOTIFY_
DISABLE
13 RQ_MANUAL_CTRL
14 RQ_REMOTE_CTRL
15 RQ_PROGRAM
16 RQ_CLEAR_RESET
17 RQ_RESET
-1 RQ_NUL
Note that disabling the node object has no practical
effect. (This is implemented only for LonMark
compatibility.)
10-8
Gas Detector
®
Node Object Sensor Object
Implementation Implementation
Set to enabled Send "no inhibit" command
Set to enabled Send "inhibit all" command
Retransmit status Retransmit status
Send capability report
Set to enabled Equivalent to RQ_NORMAL
Send "reset alarms and
faults" command
Equivalent to RQ_NORMAL
Send "inhibit alarms"
command