Com Loops - Panasonic MEW01 351 Planning Manual

Panasonic Electric Works Nordic AB
MEW01351 Rev: -
5.2
Planning Instructions Fire alarm system EBL512 G3, V1.1.x

COM loops

Each control unit has four COM loops (0-3) to which the loop units
are connected. Connections according to dwg 512 G3 – 25, - 31, - 36,
- 37 & - 38.
On each COM loop can up to 255 COM loop units be connected
(COM loop address 001 – 255). Regarding type and number of COM
loop units in relation to the cable length / type, see dwg 512 G3 – 41
and chapters "COM loop cable length", page 145 and "Current
consumption", page 148.
NOTE! In total, up to 1020 (4 x 255) COM loop units can be used
but only 512 can be alarm points, according to EN54-2.
Each COM loop unit has a COM loop address (e.g. 123) and
depending on the loop number (e.g. 0) and the control unit number
(e.g. 04) each COM loop unit gets a technical number (04 0 123).
Each alarm point and zone line input has a fire alarm presentation
number (Zone-Address), e.g. 001-01. See EBL512 G3 Operating
Instructions MEW01163 for more information.
Break or short circuit on a COM loop
Normally the control unit communicates with the COM loop units in
the A-direction only. In the B-direction is only the COM loop voltage
checked, in order to find a break on the loop.
A break or short circuit on a COM loop will generate a fault in the
control unit within 60-100 seconds (EN54-2 requirement).
A single break (cut-off) on a COM loop (open circuit).
The following will happen:

Since not all COM loop units are found by the control unit, the
communication starts in the B-direction also.

Since it is a single break, all units will now be found by the
control unit. A fault will be generated and a fault message will be
shown in the display:
FAULT: Cut-off loop x, control unit xxSCI nn
<-> SCI nn
NOTE! nn = A, 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12,
13, 14, 15 or B.

th
Each 10 minute a new attempt is made to communicate in the
A-direction only, i.e. when the break is repaired / corrected, the
communication starts again in the A-direction only, within 10
minutes.

Regarding Fault acknowledge, see the EBL512 G3 Operating
Instructions MEW01163.
Two or more breaks on a COM loop.
The following will happen:
22