7.7 NMRR / CMRR
NMRR
(Normal Mode Rejection Ratio)
The UNITEST Hexagon multimeters are equipped with the
NMRR mode.
This mode absorbs undesired AC voltage noise which
could falsify DC current or DC voltage measurements.
In general, the NMRR is indicated with reference to dB. The
UNITEST Hexagon series is specified to >60 dB at 50/60
Hz.
CMRR
(Common Mode Rejection Ratio)
DC voltage shares can be present at the COM as well as the
voltage input socket, with reference to the ground.
The UNITEST Hexagon multimeters are equipped with the
CMRR mode.
This mode absorbs DC voltage shares which may cause
digit jumps or offsets.
The CMRR mode for the UNITEST Hexagon multimeters is
specified to >60 dB at 0...60 Hz in AC voltage ranges and to
>120 Hz at 0 Hz, 50 Hz and 60 Hz for DC voltage ranges.
8.0 Maintenance
When using the instrument in compliance with the instruc-
tion manual, no special maintenance is required.
Should operational problems occur during daily use, our
consulting service (phone 0049(0)7684/8009-29) will be
at your disposal, free of charge.
For any queries regarding the instrument, please always
quote product designation and serial number, both marked
on the type shield label on instrument rear.
If functional errors occur after expiration of warranty, our
after sales service will repair your instrument without de-
lay.
65
Special Function / Maintenance
ENGLISH
