
Page 26
7.2 Outstation Alarm Handling
As well as indicating fault conditions on the Heartbeat LED (as described in section 3.2), a
Nano_Link
outstation also
indicates them on digital outputs (if equipped). It does this by logically ANDing the digital inputs sent to it by the
remote station with the alarm flags. The outputs are thus as follows (digital state 1 = contact closed, 0 = contact open):
Digital
Output
State Meaning
Heartbeat
LED
1
Base-station digital input 1 = 1
and
No comms alarm
Flashes continuously @ 4 flashes per second
1
0
Base-station digital input 1 = 0
or
Lost communication with base-station
If comms alarm:
Flashes 3 out of every 4
1
Base-station digital input 2 = 1
and
Outstation battery/mains supply is good
Flashes continuously @ 4 flashes per second
2
0
Base-station digital input 2 = 0
or
Outstation battery/mains supply is low
If battery/mains supply low:
Flashes 2 out of every 4
1
Base-station digital input 3 = 1
3
0
Base-station digital input 3 = 0
1
Base-station digital input 4 = 1
4
0
Base-station digital input 4 = 0
All outputs can therefore be used to replicate the corresponding input at the remote end, with the proviso that outputs 1
and 2 will de-energise under fault conditions. (In the event of a comms failure, outputs 3 and 4 will hold their last valid
state).
If the user wants dedicated alarm outputs, he must insure that inputs 1 and/or 2 at the remote site are permanently
energised, so only digitals 3 and 4 are usable.
Содержание Nano Link IP67
Страница 40: ...Page 38...