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6
DS308EA
| Installation Guide | 9.0 Other Features
Table 3: Mode Switching
Desired Action
Control Voltage (Terminal M)
Turn on Night
Mode/Reset
Stored Alarm
ON (for more than 20 seconds)
Turn off Night
Mode/Reset
Stored Alarm
OFF
Turn on Walk Test
(if off)
ON (for more than 5 seconds, but less than
20 seconds)
Turn off Walk Test
(if on)
OFF (for more than 1 second, but less than
20 seconds)
Day Mode:
Disables the alarm memory and allows the
LED (if activated) to operate normally.
Memory:
When DS308EA is in the Night Mode, the
memory is activated, allowing the detector to store an
alarm for display when switched to Day Mode.
Night Mode:
Enables the alarm memory and disables
the LED operation.
Walk Test:
When DS308EA is in the Walk Test Mode,
the LED indicates the current alarm status regardless of
the setting of the LED ON/OFF switch (Switch 1). A
stored alarm is displayed when the memory input is
switched to Day Mode.
9.2
Anti-Masking/Spray Detection
The Anti-Masking/Spray Detection option prevents
accidental or intentional blocking of the detector by
detecting an object placed in close proximity of the
detector or detectors sprayed with a foreign substance.
The Anti-Mask function is always enabled. If you
want to disable this function, cover the Anti-Mask
Transmitter (see Figure 4) with masking tape.
It takes approximately 25 seconds for the
detector to react to a masked or sprayed
condition if the Anti-Mask Timer is enabled.
See Section 5.3 Spray Detect (Switch 3).
If the Anti-Masking circuitry activates, a supervision
trouble condition occurs, the Alarm/Test LED flashes
three times, and the trouble relay activates.
The Anti-Masking circuitry may interpret removing and
replacing of the cover as an attempt to mask the
detector. After a 10-second quiet period, the trouble
condition automatically resets upon the next alarm
activation. Also, momentarily removing power from the
detector resets the trouble condition.
The size of the Anti-Mask Detection Zone varies
depending on the setting of Switch 3 (Spray Detect ON/
OFF). See Figure 14.
10.0 Final Tests
For better results, particularly in noise-prone
environments, the detector noise level can be measured
at the noise voltage pins, which are included behind a
metal flap on the circuit board (see Figure 4). This
feature can also be used for troubleshooting false alarms
generated by environmental changes. When performing
final tests, test both channels one at a time.
1.
Connect a DC voltmeter to the Noise Voltage pins
using the Bosch TC6000 test cable (see Figure 4).
2. Set meter scale for 3.0 VDC.
The base reference level for reading background
noise is approximately 2.5 VDC.
Installations in quiet environments result in a steady
reading between 2.4 VDC and 2.6 VDC.
During the Walk Test, voltage changes greater than
0.75 VDC from the reference level are desirable for
good catch performance. If changes are less than
0.75 VDC, the device may fail to respond if the
temperature difference between the intruder and the
background is minimal.
3. Turn on all heating and cooling sources that are
normally in operation during times of protection.
4. Stand away from the unit and outside the coverage
pattern. Then monitor the background noise for at
least 3 minutes.
Readings should not deviate from the reference
level by more than ±0.15 VDC.
For readings outside these limits; eliminate the
cause, re-point the unit slightly, or mask off the
affected zones.
Figure 14: Anti-Masking Coverage
60 cm
(24 in.)
2
1
3
1 - Anti-Mask Detection Zone with Switch 3 (Spray Detect) OFF.
2 - Anti-Mask Detection Zone with Switch 3 (Spray Detect) ON.
3 - Keep Out Zone. Do not mount moving objects (such as
curtains or doors) within this area.
