Servicing; Tuning Zero And Span - Samson 6134 Mounting And Operating Instructions

8 Servicing

The work described in this section is only to
be performed by personnel appropriately
qualified to carry out such tasks.
DANGER
!
Risk of fatal injury due to the ignition of an
explosive atmosphere.
Î Observe EN 60079-14 (VDE 0165,
Part 1) for work on the converter in po-
tentially explosive atmospheres.
Î Work in potentially explosive atmo-
spheres must only be performed by per-
sonnel who has undergone special train-
ing or instructions or who is authorized
to work on explosion-protected devices
in hazardous areas.
DANGER
!
Loss of Ex d protection due to opening the
enclosure cover or damage to the thread.
Î Keep the enclosure cover firmly closed
during operation.
Î Put the device out of operation when its
cover thread or connecting thread is
damaged. Replace it with a new device.
Note
The device was checked by SAMSON before
it left the factory.
− The product warranty becomes void if
service or repair work not described in
these instructions is performed without
prior agreement by SAMSON's After-sales
Service.
EB 6134 EN
− Only use original spare parts by
SAMSON, which comply with the original
specifications.

8.1 Tuning zero and span

The ZERO and SPAN potentiometers are lo-
cated directly on the front panel of the
rail-mounting unit. To access these potenti-
ometers on the field unit, unscrew the enclo-
sure cover (see Fig. 8-1).
Î Put any components upstream of the con-
verter (e.g. air line for the input signal)
out of operation.
Î Remove any lines to upstream compo-
nents and any wires to downstream con-
trol equipment (electric output signal
line).
Î Connect the pneumatic input to a pres-
sure instrument and the electric output to
a measuring instrument with sufficient
accuracy.
Î Unscrew the enclosure cover of the con-
verter.
Î Tune zero:
Î Set the input signal to 0.2 bar.
The output signal of the measuring
instrument must now indicate 4 mA.
Î Correct deviations at the ZERO po-
tentiometer.
Î Tune span:
Î Raise the input signal from 0.2 bar to
1 bar.
The output signal of the measuring
instrument must now indicate 20 mA.
Servicing
8-1