Service Manual
AT235
10
3 Calibration Procedure
This chapter contains calibration standards for AT235.
3.1 Service, adjustment and repair
This instrument can be serviced, adjusted and repaired without losing the validity of the CE-marking, provided the
measuring equipment fulfills the below requirements, the adjustment procedures are followed, and staff have the
necessary qualifications as approved by Interacoustics.
Before any attempt is made to calibrate AT235, it must have been powered on for 3-5 minutes in an ambient
temperature that is both stable and comfortable.
Annual calibration (ANSI/ASA S3.6)
The calibration procedure will validate all relevant performance requirements given
in ANSI/ASA S3.6. After the audiometric equipment has been submitted for
calibration, a calibration certificate showing the values recorded must be filled out,
signed and dated by the technician, demonstrating that the instrument conforms to
all relevant requirements given in this standard.
It is considered good practice to perform annual checks of the audiometric test room’s noise level as part
of the annual calibration using the applicable table per ANSI/ASA S3.1
American National Standard
Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms
to ensure that audiometer
performance will not be affected by any changes in the audiometric test room’s noise levels.
Annual calibration (IEC 60645-1)
A basic calibration must be performed by a competent laboratory. The procedure should be such that, after the
audiometric equipment has been submitted for a basic calibration, it should meet the relevant requirements given
in IEC 60645-1.
When the instrument is returned after basic calibration, it should be checked in accordance with procedures outlined
in calibration checklist (Refer to section
3.1.1 Hardware calibration – requirements
The hardware calibration is typically only performed during the production of the device and therefore does not
require adjustment in the field, except in certain circumstances. Refer to
Appendices - Technical specifications
further information.
CAUTION
