D9412G/D7412G/D7212G Installation & Troubleshooting Quick Reference Guide
D9412G/D7412G/D7212G
Page 15
© 2004 Bosch Security Systems, Inc.
43700F
Troubleshooting
3.8
Problems with the D8125 POPEX Data Expansion Loops
EMI (Electro-magnetic Interference), excessive resistance, or intermittent grounds, shorts, or opens on the data expansion
loop can cause erratic or intermittent functioning of points. If EMI may be a problem, see Section 3.9 EMI on Long Wire
Runs on page 16. AC induction on the data expansion loops must be less than 1.0 VAC. If EMI is
not
suspected as the cause
of the problem, follow the procedures below to find the source of problems on the data expansion loop or use the Zonex
Point Identification Validation Process (P/N: 43049) for a detailed procedure and worksheets to identify and validate all
points.
3.8.1
Metering the Loops
Before following the procedures below to meter the data expansion loops, check Table 10 to verify the correct gauge wire for
the length of the data expansion loops was used.
Maximum Length of all Data
Expansion Loops Combined
AWG
Length in ft. (m)
22 1800
(548)
20 2890
(881)
18 4600
(1402)
16 7320
(2231)
14 11650
(3551)
Table 10: Data Expansion Loop Wire Specifications
When metering the loop, monitor it long enough to observe an intermittent problem.
To meter the data expansion loop without POPITs connected to it:
1.
Disconnect the loop from the POPEX Module.
2.
Twist the positive and then the negative wires together at each POPIT location so that the positive and negative
wires are continuous to the last POPIT location.
3.
At the last POPIT location twist the end of the positive wire to the negative wire to form one continuous loop.
4.
Meter the loop for continuity from the point where it connected to the POPEX Module. Resistance for the
entire loop must be less than 60
Ω
. If there is no continuity, find and repair the open on the loop.
5.
Still metering for continuity, untwist the negative and positive wires at the last POPIT location. If the meter
does not show an open condition, find and repair the short on the loop.
6.
Twist the positive and negative wires at the last POPIT location back together.
7.
Meter the loop for continuity to Terminal 10 (earth ground). If there is continuity, find and remove the foreign
ground on the loop.
8.
Meter the loop to Terminal 10 for AC voltage. AC induction on data expansion loops must be less than 1 VAC.
Try using shielded cable to reduce AC induction if the AC voltage exceeds 1 VAC.
