Node Object - Honeywell Apex Technical Handbook

MAN0604_Issue 09_02-2013
2110M8030
APPENDIX A - SPECIFICATIONS
A.4.2 Node Object
The Node object has one network variable input and three network variable outputs.
nviRequest input and nvoStatus output
The Node object implements SNVTs for object request and status. These complex variables are
required for LonMark compatibility and are capable of conveying a great deal of information between
the instrument and a Graphical user Interface (GUI) computer or a network management tool but are
less appropriate for peer-to-peer communications.
It is possible to disable the sensor, reset alarms and perform other functions using nviRequest.
The complete list of commands is in the subsequent table.
Furthermore, nvoStatus reports information about the sensor in a compact format such as when
an alarm or fault is present. The complete usage of nvoStatus is listed in the table at the end of
this section.
nvoFaultD output
This simple variable of type SNVT_lev_disc can be bound to common LonWorks relays to activate
lights or perform shutdown. This normally has the value ST_OFF. If maintenance is needed soon
(for example because the cartridge is near the end of its life) then this variable will have the value
ST_LOW.
If a serious fault exists that compromises the ability to detect gas then this variable will have the
value ST_MED.
nvoFaultS output
This variable containing two one-byte fields is more complex than nvoFaultD. nvoFaultS.state
normally is 0 but will have the value 1 if the sensor has any fault or warning.
If nvoFaultS.state is true then nvoFaultS.value will have an error number to facilitate preliminary
diagnosis over the network. Note that Echelon's LNS applications display the .value field divided
by two.
nvoFaultS Transmitter
.value Code
2 1
8 4
10 5
12 6
14 7
42 21
44 22
46 23
48 24
50 25
52 26
Cause
Watchdog Restart Occurred
Momentary Cartridge Failure
Temperature Warning
Approaching End of Cell Life
Calibration Needed Soon
Sensor Failed
No Cartridge
Wrong Cartridge
Cartridge Failed
Temperature Error
End of Cell Life
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