Operation; Checking Zero And Span; Checking Zero - Samson 611 Mounting And Operating Instructions

Operation

6 Operation
DANGER
!
Risk of fatal injury due to the ignition of an
explosive atmosphere.
Incorrect installation, operation or mainte-
nance of the i/p converter in potentially ex-
plosive atmospheres may lead to ignition of
the atmosphere and cause death.
Î The following regulations apply to instal-
lation in hazardous areas: EN 60079-14
(VDE 0165, Part 1).
Î Installation, operation or maintenance of
the i/p converter must only performed by
personnel who has undergone special
training or instructions or who is autho-
rized to work on explosion-protected de-
vices in hazardous areas.
DANGER
!
Loss of Ex d protection due to opening the
enclosure cover or damage to the cover's
thread and/or the connecting thread.
Î The enclosure cover must be firmly closed
during operation.
Î Put the i/p converter out of operation
when its cover thread or connecting
thread is damaged. Replace it with a
new device.
Note
The versions with a 0 to 20 mA input signal
do not have any switch-off electronics nor a
potentiometer to adjust zero. If the device
does not have a potentiometer for zero, the
34
zero point can only be adjusted mechani-
cally at the zero point adjuster (1.1). See
section 6.2.
Some versions also do not have a potentiom-
eter to adjust the span.

6.1 Checking zero and span

The device converts the input signal propor-
tionally into the output signal.
The signal ranges are specified on the name-
plate (see section 2.1).
In case of a mounting position that is not
horizontal or when the pressure gauge/
screw plug does not face upwards, zero and
span can be corrected by approx. 10 %
using the electronics.
If the device does not work properly for any
reason, check the zero and span.
The ZERO and SPAN potentiometers are ac-
cessible after opening the enclosure cover
(see Fig. 16).
6.1.1

Checking zero

1. Unscrew the enclosure cover.
2. Connect a pressure gauge (minimum ac-
curacy class 1) to the converter output.
3. Set the supply air to 0.4 bar above the
upper output signal range value and ap-
ply it to the device.
4. Deactivate the switch-off electronics at
the slide switch (5).
5. Set the input signal to the lower range
value using a suitable ammeter.
EB 6116 EN