WIKA Testing Instructions for Pressure Gauges
5
061744 09/
009 GB/D/F/E
GB
Examples of the calculation of the permissible deviation
(linearity and hysteresis):
Scale range: 0 ... 10 bar (measuring span = 10 bar)
Class 1.6 (error limit = 1.6 %)
Permissible deviation:
=
± 0.16 bar
Scale range: -1 ... +5 bar (measuring span = 6 bar)
Class 1.0 (error limit = 1.0 %)
Permissible deviation:
=
± 0,26 bar
2.1 Process for display testing
The accuracy class is always determined at the reference standard, i.e. the
measuring point to be tested must be generated at the test specimen and the
deviation of the value measured at the measuring point is to be recorded from
at the reference standard.
The following test features must always be tested prior to the actual display
testing:
Pointer movement (smooth)
Zero error (after running through the entire scale range)
Static pressure test (differential pressure gauges) with a pressure load of the
max. overload capacity:
The zero error must not exceed the operational error limit.
Free movement of the pointer beyond the upper limit of the scale range,
however up to a max. of the 6 o'clock position.
2. Testing the display
Pressure gauge
Class
Error limit
Number of measuring
points
0.1
0.1 %
at least 10
0.
0. %
at least 10
0.3
0.3 %
at least 10
0.6
0.6 %
at least 10
1.0
1.0 %
at least 5
1.6
1.6 %
at least 5
.5
.5 %
at least 5
4.0
4.0 %
at least 5
Error limits for the display (per EN 873-1 / EN 837-3)
10 x 1.6
100
6 x 1.0
100
