6 instrument description, Tw, tb, Stw, stb – JUMO 60.5051 Explosion-protected surface-mounting thermostat, ATH-EXx Operating Manual User Manual
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6 Instrument description
Switching point
accuracy
in % of scale span, referred to the limit value at T
a
+22°C.
Mean ambient
temperature
effect
in % of scale span, referred to the limit value.
A deviation of the ambient temperature at the thermostat head and/or the cap-
illary from the +22°C calibration ambient temperature produces a shift in the
switching point:
higher ambient temperature = lower switching point
lower ambient temperature = higher switching point
TW, TB
in upper third of scale
+0
%
-4
at start of scale
+0
%
-6
STW, STB
in upper third of scale
+0
%
-5
at start of scale
+0
%
-7
Surface-mounting thermostats with end of scale
< +200°C
+200°C +350°C
> 350°C
TW
TB
STW
STB
TW
TB
STW
STB
TW
TB
STW
STB
effect due to the thermostat head, % per °C
0.08%/K
0.17%/K
0.06%/K
0.13%/K
0.14%/K
0.12%/K
effect due to capillary, % per °C per meter
0.047%/K
0.054%/K
0.09%/K
0.11%/K
0.04%/K
0.03%/K