9
Reading the Display
What the LEDs Mean
The dosimeter uses color-coded LEDs to display noise dose in percent.
Green
(Safe): Noise dose is below 100%
Yellow
(Borderline): Noise dose is greater than 100% and less than 200%
Red
(High Risk)
:
Noise dose is greater than 200%
Rate
A slow flashing LED at 25% means that the noise dose is a t or below 25%
(i.e., between 0% and 25%). When the noise dose reaches 25%, the 25% LED
flashes rapidly indicating that it is between 25% and 50%. Similarly, when the
dose exceeds 50% but is less than 100%, the 50% LED flashes rapidly, etc.
What Dose % Means
Simply stated, noise dose is a measurement of noise exposure. It is the
combination of the amount of sound and the amount of exposure time. Think of
100% as the limit of safe exposure, 200% as two times the permissible exposure
limit, 400% as four times the limit, etc. The risk of hearing impairment gro ws with
increasing noise dose. In some susceptible persons, a 100% dose indicates
enough noise exposure to cause a small amount of hearing loss over time.
8
Auto Shut Off
In
Normal Mode
, the dosimeter shuts off 8 minutes after displaying the 16-hour
accumulated daily dose. In
Quick Check
, the dosimeter shuts off 1 minute after
displaying the estimated dose per hour.
Low Battery Indicator
The ER-200 measures battery strength each time the dosimeter is po wered ON.
If batteries are weak, a pair of lights flashes for 3 seconds. At the first low-battery
alert, there is typically enough battery power remaining to measure a 16-hour day’s
dose. When batteries are too low to complete a 16-hour measurement c ycle, a pair
of lights will flash at startup and the unit immedia tely shuts OFF.
LED
Dose %
Risk Factor
green (slow flash) <25%
No risk of hearing loss
green (fast flash)
25%
No risk of hearing loss
green
50%
1/2 daily dose reached
yellow
100%
Limit of permissible exposure
red
200%
2x allowable daily dose
red
400%
4x allowable daily dose
red
1600%
16x allowable daily dose
red
3200%
32x allowable daily dose