Fema DCM Series Assembly And Operating Instructions Manual page 33

All pressure switches from DCM, DNM, DNS, VCM, VNM, VNS and DDCM series, as well as
their Ex versions, are calibrated by the manufacturer for falling pressure. This means for:
Switching with rising pressure:
(lower range limit)
The smallest switching point that can be set is higher than the start of the scale by the value of
the switching differential. The device then switches back to the start of the scale in case of falling
pressure.
(upper range limit)
The highest switching pressure that can be set is the end point of the scale. The device switches
back as soon as the pressure has fallen by the value of the switching differential.
Switching with falling pressure:
(lower range limit)
The lowest switching point that can be set is the start point of the scale. The device switches back
as soon as the pressure has risen by the value of the switching differential.
(upper range limit)
The highest switching point that can be set is lower than the end of the scale by the value of the
switching differential. The device switches back as soon as the pressure has again risen to the scale
end value.
The following applies for all devices:
All switching and reset points must be within the limits of the specified setting range given in
the technical data sheet.
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