BSD-340-user-guide-eng, Doc. 1004474-2, 2020-09-18,
Autronica Fire and Security AS
Page 8
3. AutroSafe now continues as described in chapter 2.3.1 above.
4. When the loop raise is complete, AutroSafe sets state Enabled on the loop, and loop
polling starts again.
Note! RESET does not cause a loop raise. The operator must disable, then enable a loop to
raise it manually.
2.3.3 Loop Polling
According to EN-54, AutroSafe must report missing detectors within 100 seconds. AutroSafe sends
a POLL message to all detectors and requires an Acknowledge in return as proof of life.
1. BSD-340 divides polls over time based on the number of detectors so that one complete
loop scan takes 60 seconds.
BSD-340 updates an internal table indicating if a detector is alive or not. This scanning is
independent from AutroSafe’s polling.
2. AutroSafe polls BSD-340 every 20 seconds (to keep total time under 100).
BSD-340 then reports “Point Not Responding” for all detectors that does not answer with
acknowledge message.
2.4 Crosstalk
Crosstalk, or cross loop communication, occurs when radio signals transmitted in one loop is
received by the BSD-340 controlling another loop. This happens because the loop cables work like
antennas and may occur when cables for multiple PowerLoops are run in parallel or when BSD-
340 LoopDrivers are installed close to each other. In general, PowerLoops should not be pulled in
parallel, and
BSD-340 PowerLoop Drivers should be distributed around the site using AutroFieldBus, and be
located as close to the PowerLoop as possible.
Crosstalk is electric noise, and can be divided into two degrees of severity:
• Crosstalk/Full Crosstalk:
A complete message is transmitted between PowerLoops without errors, lost or ruined
bits.
Note! The PowerLoop can, to some extend work fairly good when there is error free
crosstalk, however this is not an acceptable situation and needs to be fixed.
• Noise/Partial Crosstalk
Weak reception causes a message to be partially transmitted between PowerLoops or has
bit errors when received by another loop.
Note! Noise causes retransmissions, which in turn may ruin messages on other loops, so
this is the worst situation.
2.4.1 Possible crosstalk issues
When crosstalk occurs, the system may experience several issues:
1. Restart messages from one loop received by another loop.
➢ During loop raise: Faults could be new branches or wrong detector type
compared to configuration. INIT could often end with loops disabled
automatically and fault messages.
➢ During operation: Loop would be powered down and raised, making Restart
messages that would disturb other loops.
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