Process For Display Testing - WIKA 811 Instrucciones

2. Testing the display
Error limits for the display (per EN 873-1 / EN 837-3)
Pressure gauge
Class
0.1
0.
0.3
0.6
1.0
1.6
.5
4.0
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:
Scale range: -1 ... +5 bar (measuring span = 6 bar)
Class 1.0 (error limit = 1.0 %)
Permissible deviation:

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.
WIKA Testing Instructions for Pressure Gauges
Error limit
0.1 %
0. %
0.3 %
0.6 %
1.0 %
1.6 %
.5 %
4.0 %
10 x 1.6
= ± 0.16 bar
100
6 x 1.0
= ± 0,26 bar
100
Number of measuring
points
at least 10
at least 10
at least 10
at least 10
at least 5
at least 5
at least 5
at least 5
GB
5