The ER-200 has two modes of operation: Normal Mode measures and displays noise dose continuously for up to 16 hours, and Quick Check measures noise for two minutes, then calculates and displays the estimated dose per hour.

In Normal Mode, the dosimeter provides an early warning that the user is approaching over exposure and should use hearing protection. Quick Check provides a quick and easy way to measure a specific noise source to determine if permissible exposure levels will be exceeded (e.g., loud equipment, vehicles, power tools, music concerts or sporting events).

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 at 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 grows 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.

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

Note: Use the foam windscreen when measurements are made outdoors. Do not blow into the microphone opening because incorrect noise dose readings will result.

Normal Mode
(Daily Dose) Test Time: Up to 16 hours

Power ON:

• Press and release the power button. The red 3200% LED is steady, followed by one LED sweep.
• The previously measured dose displays for about 10 seconds while the red 3200% LED remains steady.
• If the previous dose was 3200%, the red 3200% LED flashes.
• When the red 3200% LED turns off, a slow flashing of the green 25% LED begins, indicating the start of the measurement.
• The dosimeter continuously displays the current dose, indicated by a flashing LED.
• After 16 hours, the accumulated dose is displayed for about 8 minutes.
  • During the display period, the red 3200% LED is steady and the flashing LED indicates the dose. In cases where the accumulated dose is 3200%, the red 3200% LED flashes.
  • At the end of 8 minutes, the dosimeter automatically shuts off.
• The dose is stored in memory and is displayed when the device is powered on again.

Power OFF:

• To power off the dosimeter prior to its automatic shutdown: Press and hold the power button until a pair of lights flashes (about 3 seconds) then release the button.
• Wait 5 seconds before powering ON again.

Quick Check
(Estimated Hourly Dose) Test Time: 2 minutes

Note: Use the foam windscreen when measurements are made outdoors. Do not blow into the microphone opening because incorrect noise dose readings will result.

Power ON:

• Press and hold the power button for 5 seconds. The red 3200% LED is steady, followed by several LED sweeps. Release power button.
• The previously measured dose is displayed for about 10 seconds while the red 3200% LED remains steady.
• When the red 3200% LED turns off and the green 25% LED flashes, the two-minute Quick Check starts.
• After 2 minutes, the steady red 3200% LED indicates the test is over.
  • The flashing LED indicates the estimated dose per hour.
  • During the display period, the red 3200% LED remains steady, unless the estimated dose is 3200%, then the red 3200% LED flashes.
  • The estimated dose per hour displays for 1 minute, then the dosimeter shuts off.
• The dose is stored in memory and is displayed when the device is powered on again.

Power OFF:

• To power off the dosimeter prior to its automatic shutdown: Press and hold the power button until a pair of lights flashes (about 3 seconds) then release the button.
• Wait 5 seconds before powering ON again.

Windscreen

For accurate measurements, the 35 mm (1.4") windscreen included with the ER-200 should be used when noise is measured outdoors or near any turbulence, e.g., from a fan. The foam windscreen allows accurate measurement in winds up to 15 to 20 mph. Note: Blowing across the microphone opening on the dosimeter can cause the same turbulence as a 50 mph wind.