ML1144 timings and battery consumption
The battery consumption is very important in this system and the synchronising system used allows the
units to maximise battery life. For example, take the worst case, zone 2 or 3 radio, identity number 15.
Idle current is approximately 100μA
at 4.65 seconds in every 8 second group
= 0.06mA contribution
TX contribution: 750ms at 2.4mA (processing)
44ms TX actually ON, at 29mA
three times over
RX contribution: 850ms at 9mA (main listen)
= 1.197mA
= 2.36mA
100ms at 12mA (sync listen, LED on)
In worst case sync (receiving a sync from a zone 2 unit with slave ID of 14) the sync listen contribution
alone rises by 0.9mA, giving us 3.26mA total current.
So an average current would be around 3.5mA.
3.5mA on 20Ah Alkaline battery (6 x D) will last 5700 hours: which is 34 weeks (over eight months)
(A PP3 battery will run the unit for a week)
Response time
Alarm "on" activation is faster than "alarm off" (for obvious safety reasons).
Whenever a unit receives either a sync or reply message with any alarm state bit set, it will enter the
"alarm on" state and activate its relay. This means that when a unit is activated, the closest units to it
(the ones in range) will go into alarm mode as soon as they receive its transmitted message. This will
occur within one group, and possibly within the same frame if the activation precedes the unit's slot.
This is the fastest possible response time for the system. Generally the worst case should be considered:
the time for a unit in zone 4 to alarm in response to the activation of another zone 4 unit, on the "other
side" of the network.
In this case, the data bit must propagate in to the master (4 frames) and out again (4 frames): 8
seconds, but to this we must add the even worse situation, that the activation occurs just after the unit's
assigned slot: in this case a whole group will tick past before the activated unit will get to transmit its
"new" data ... so 16 seconds will elapse.
Setting
These units are supplied in "slave" and "master" varieties.
To maximise operating area, the master should be located in the middle of the site.
The high order 4 DIP switch bits are the 4 bit global (site) address. This must be the same on all units
in a system.
Each unit on system must have a unique number.
The local ID on a master should be set at 0000
Local Slave ID numbers (low order DIP switch) must be set between 1 and 15.
Local ID of zero on a slave unit is a special case, turning the unit into a "drone"
A drone listens but does not send data. This is useful where you want to have an indicator only like a
siren but no push button alert. It is also useful if you use the AUX1 serial output pin to look at the data
on the system. If the data is fed into a board which contains an OD28 output decoder chip it allows the
user to display LED indicators of which unit has activated. The OD28 ICs can be purchased separately
to enhance the system.
Serial link
A serial link via JP7 AUX1 is provided which has two modes:
1) If the JP4 jumper link nearest the radio module is fitted, the DataStream is a human-readable
ASCII diagnostic stream of 1s and 0s indicating status of the system and each cycle outputs
effectively the message which is being sent to the system from the master
2) If jumper is removed a special OD28 binary stream is sent every cycle and therefore is used by
Radiometrix Ltd
M1144 Application Boards
page 5
RADIOMETRIX [ RADIOMETRIX LTD ]
