Ttp48: Noise On Wire - Bosch D9412GV2 Troubleshooting Manual

D9412GV2/D7412GV2 | Troubleshooting Guide | 3.0

TTP48: Noise on Wire

Initial Actions
You must understand the devices and wiring splices
contained in the circuit you are troubleshooting. If you
do not know this information, trace the wiring as
required.
If you are unsure of which circuit to
troubleshoot, refer to Section
Identifying Addressable Points on a Circuit
on page 116.
Procedure
Disconnect both conductors of the wire from the control
panel or module. Touch the probe (from your Tone and
Probe Test Kit) to one conductor. Turn the probe on. Then
repeat for the other conductor.
Did the probe remain silent for both conductors?
Connect the red lead from your digital voltmeter
(DVM) to one conductor. Connect the black lead to a
known good earth ground. Set the DVM to measure
VAC. Repeat with the other conductor.
Does the DVM read >1 VAC on either conductor?
The problem is electrical noise, possibly caused
by a data circuit that runs parallel to part of the
wire you are troubleshooting.
Select the conductor that produced the most
noise from your probe. Disconnect your DVM
from the conductor.
For the rest of this TTP, always check for
noise by touching the probe to the same
wire location used at the beginning of this
procedure.
Is there more than one piece of equipment
connected to this conductor, or are there
wire splices on the conductor?
Disconnect the other end of the
conductor you are troubleshooting.
Touch the probe to the conductor again.
Did the probe remain silent?
The problem is the location where the
equipment was installed. Relocate the
equipment.
A B C
102
4.1.4
Re-run the wire, avoiding all data
circuits. Then reconnect
equipment on the circuit.
Troubleshooting
A B C
IMPORTANT: The rest of this procedure
uses a half-split troubleshooting approach.
By answering the following question, you
divide the circuit in half to determine the
half of the circuit that is the source of noise.
This half is the "affected circuit".
By repeating the question, you divide the
affected circuit in half again to determine
the half of the affected circuit that is the
source of noise. That half becomes the
affected circuit.
Repeat the following question as many
times as necessary until you reduce the
affected circuit enough to identify the
source of noise. Refer to
page 104
After you identify the source of noise, run
the wire away from the source of noise.
During the rest of this TTP, if the TTP states
"repeat the process and question above",
return to this location in the TTP.
Disconnect the middle device or splice in the
affected circuit. Touch the probe to the noisiest
conductor identified at the beginning of this
procedure.
Did the probe remain silent?
Refer to
problem is between where you
disconnected the device or splice and
either:
-
-
Refer to Figure 58
is between where you disconnected the device
or splice and either:
- the end of the circuit, or
- the location of the device or splice you
disconnected the last time the probe did
not remain silent. Reconnect the device or
splice, then repeat the process and
question above.
A B
Bosch Security Systems, Inc. | 11/05 | F01U011024B
Figure 58
.
Figure 58 on page 104. The
the location of the probe, or
the location of the device or splice
you disconnected the last time the
probe remained silent. Reconnect
the device or splice, then repeat
the process and question above.
on page 104. The problem
on