GAI-Tronics 12389-001 NOVA PA/GA Systems S.M.A.R.T. Modules - Manual (Page 17)

Pub. 42004-674L2H
NOVA P UBLIC A DDRESS S YSTEMS - S.M.A.R.T. M ODULES P AGE 15 of 24
f:\standard ioms - current release\42004 instr. manuals\42004-674l2h.doc
12/13
System Optimization
After the paging attenuator reference level and noise reference level have been stored in memory, they are
used as a starting point whenever a power-down/power-up has occurred. From this point the
microprocessor measures the “new” current noise level, sums it with the stored noise reference and uses
the difference to add to or subtract from the reference paging attenuator value. This result, always in
RAM is the “current attenuator value.” This process continues indefinitely with exception to the actual
paging period, which is detected by the logic closure input or command via RS-485.
The relationship between noise level and attenuator setting is linear at normally 1:1 ratio. As ambient
noise increases in 3 dB steps, the paging audio level is raised by an equivalent amount in 3 dB steps.
However, the ratio between the change in the noise level and the change in the paging level can be
modified to a larger ratio by adding additional steps of paging volume for every step of increase in
ambient noise. The ratio then would be 1:1+N where N is the number of additional steps required.
For example, if N = 1 and noise goes up by 3 dB, the paging volume goes up 6 dB. This ratio is referred
to as the kick-up ratio and the N number as the kick-up value. This feature is most useful when the
predominant ambient noise in the zone is full-spectrum in nature and tends to mask paging audio more
quickly that single-tone (whine or hum) type noise. Examples of full spectrum noise would be the sound
of gravel running down a chute or the hiss of a large volume of air pressure being released.
If the paging level simply needs to be further adjusted (tweaked) without changing the kick-up ratio, then
perform the paging level update procedure described below.
The minimum paging attenuation may also be established in order to maintain a minimum area coverage
even under completely quiet ambient conditions. This is referred to as Page Min. and is expressed in 3
dB SPL steps.
N OTE : If at any time the system is in any of the Programming modes and no button activity has been
detected for 15 minutes, the system automatically returns to the Normal Operating mode using the
operating values that were previously in the memory.
Paging Level Update
1. Ensure that the system is in the Normal Operating mode: P
OWER
LED ON – steady.
2. Press the L
EVEL
button for 3 seconds. The A
CKNOWLEDGE
LED must flash for one second, and the
P OWER
LED begins to flash on and off. (The C is in LVL mode.) Press the U
P
or D
OWN
buttons
to modify the paging level.
3. Press the L
EVEL
and S
AVE
buttons together for 3 seconds to save the new paging level. (The C
stores only the new attenuator reference level in NVRAM.) The P
OWER
LED ceases flashing
indicating the return to the Normal mode.
4. The Bar Graph LEDs continue to indicate the audio level coming from the ALC Remote Module for
approximately 5 minutes after a level-save operation and then extinguish. If at any time after the
time-out period you wish to view the level indication, press the L
EVEL
button momentarily (less than
3 seconds). The Bar Graph LEDs again indicates the level for 5 minutes.