APPENDIX A - SPECIFICATIONS
54 27 Calibration Required
62 31 Transmitter Alarm Setting Failure
64 32 Sensor Comms Failed
102 51 FatalFault
202 101 TransmitterFailed
204 102 TransmitterFailed
226 113 Transmitter Failed
A.4.3 Sensor Object
The sensor object has one network variable input and eleven network variable outputs.
nviResetAlm input
This network variable causes latching alarms and faults to be reset. The reset will only take place if
thecauseofthefaultoralarmnolongerexists.Additionally,theresetonlyoccurswhenanon-zero
update is sent to this input.
This means that sending an ST_LOW to this input once will not have any effect on alarms or faults
that occur later. This input resets both the local relays and LonWorks network variables.
nvoAlmL output
This network variable normally has the value ST_OFF. When a level 1 alarm exists the alarm1 relay
will be activated and this output will have the value ST_LOW.
When a level 2 alarm exists the alarm2 relay will be activated and this will produce ST_MED.
nvoAlm2 output
This variable normally has the value ST_OFF. When a level 2 alarm exists this will have the value
ST_MED.
This network variable is provide for use with common shutdown relays that are not capable of
discriminating between ST_LOW and ST_MED in installations where discrimination between alarm1
and alarm2 is desired.
nvoAlarmThresh1 and nvoAlarmThresh2 outputs
These network variables indicate the current alarm thresholds of this instrument. Gas concentrations
greater than the amount reported in these variables will cause the alarms to activate. See the related
subsequent discussion of nviHighLim1 and nviHighLim2.
The units are the same as the front panel display and will be indicated by nvoConcType, below. The
units will be ppm, %LEL and %V/V respectively when gas sensor cartridges for toxic, explosive and
oxygen gasses are installed.
For example if an H
2
cartridge is installed and nvoAlarmThresh1 is 50.00, this means that alarm1 will
activate when the H
2
concentrations exceeds 20,000 ppm since LEL for H
2
is 40,000 ppm.
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