Specifications

Castle Care-Tech Ltd. Engineering
Page 11 - 10 Chapter 11
Table of resistance readings for
measurement at step 6, above:
No of
biscuits
Nominal
resistance
No of
biscuits
Nominal
resistance
No of
biscuits
Nominal
resistance
1 87K 11 7.9K 21 4.1K
2 43.5K 12 7.3K 22 3.9K
3 29K 13 6.7K 23 3.7K
4 21.8K 14 6.2K 24 3.6K
5 17.4K 15 5.8K 25 3.5K
6 14.7K 16 5.4K 26 3.3K
7 12.5K 17 5.1K 27 3.2K
8 10.9K 18 4.8K 28 3.1K
9 9.7K 19 4.6K 29 3.0K
10 8.7K 20 4.4K 30 2.9K
NOTE: These readings are a
guide to the effectiveness of the
wiring, and that all biscuits are
correctly connected. This is NOT
a diagnostic test for the biscuits
themselves. A range of
tolerance, roughly equivalent to
the next figure above and below,
should be expected.
Important Notes for
installing iD systems
A transient generated by an iD
biscuit whilst being addressed
will occasionally cause another
biscuit to perform a counter
reset. This can result in the
biscuit affected signalling
again, at an incorrect address,
and thus generate a ‘twin
device’ alarm.
To eliminate this possibility a
small value capacitor (0.01 "F
recommended) should be
wired across the iD line at a
convenient biscuit or junction
box, at the end of each iD spur.
A supply of suitable capacitors
(marking code “103”) is supplied
with the Euro-MERiDIAN End
station / ZEM.
Remember that some sites may
not be suitable for the use of iD
systems, whether because of the
re-use of wiring of dubious
history, or the presence of
severe sources of electrical
interference.
An iD Test Meter is available
from ACT Meters Ltd. (01744
886660).
Training is recommended for all
personnel working on iD systems.
Courses are available on
application to the Sales Dept.