Camille Bauer KINAX WT 707 Mode D'emploi page 27

Bridge
–
R
ext
+
+ –
A and H
2-wire connection 3-wire connection
(4...20 mA) (different mA-signals)
A = Measuring output...
... as 2-wire connection (4...20 mA, signal in
output/powering circuit)
... as 3 or 4-wire connection (different
mA-signals)
H = DC power supply H = 12...33 V
resp. H = 12...30 V with Ex version
R = External resistance
ext
Fig. 7. Connection diagrams for 2, 3 or 4-wire connection,
without electric isolation, DC power supply.
+
R
ext
–
A
4-wire connection (different mA-signals)
A = Measuring output
H = DC/AC power supply
R = External resistance
ext
Fig. 8. Connection diagram for 4-wire connection,
with electric isolation, DC/AC power supply.
8. Setting the beginning and end of the measuring
range
The coarse adjustment of the beginning of the measuring
range consists in aligning the zero of the measured device
with the external zero mark on the transmitter. The proce-
dure was described in Section 6 "Mounting". This Section
concerns the fi ne adjustment not only of the beginning of
the range (ZERO), but also of the end of the scale (SPAN).
Firstly, switch on the power supply to the transmitter.
For versions ...
... with plug-in connector remove the ZERO/SPAN sealing
screws (2.2) (Fig. 9, left).
... with screw terminals and cable glands, remove the 3
screws (3.2) and the cover (3.1) (Fig. 6, left).
+
+
R
R
ext
ext
–
–
– +
A H A
4-wire connection
(different mA-signals)
+ ~ – ~
H
Caution! The screw terminals (4.1) are live.
The 230 V power supply is potentially
dangerous!
Place the measured device at its zero position, i.e. the
position at which the KINAX WT 707 should produce 0 mA
(three or four-wire connection), respectively 4 mA (two-wire
connection) at its output.
Should the output current differ by more than 2% from its initial
value, repeat the coarse zero setting procedure described in
Section 6 "Mounting".
+ –
H
Then adjust the "ZERO" potentiometer (Fig. 9, right or
Fig. 10) using a watchmaker's screwdriver (2.3 mm diam.)
so that the desired output current fl ows.
(2.2)
Fig. 9. Rear (2) of the transmitter with the adjustments
"ZERO", "SPAN" and "S1".
Left: Adjustments covered by the sealing screw (2.2).
Right: Adjustments exposed.
Fig. 10. Rear (3) of the transmitter with the adjustments
"ZERO", "SPAN" and "S1".
Now rotate the measured device to its opposite limit position,
i.e. the position at which the KINAX WT 707 should produce
the prescribed full-scale output current (see rating plate).
Adjust the "SPAN" potentiometer with the screwdriver as
before until precisely the prescribed full-scale output current
is measured at the output.
Then recheck the zero point and correct on the ZERO po-
tentiometer if necessary. Check the full-scale value again.
Repeat both adjustments until both zero point and full-scale
value are precise.
9. Adaptation from 2-wire connection to 3 or
4-wire connection and vice versa
Transmitters with the ordering code 707 – ...D (see Section
14 "Specifi cation and ordering information") are designed
for either a two-wire connection with an output range of
4...20 mA or a three or four-wire connection with an out-
put range of 0...20 mA.
(2)
(3)
Zero Span
S1
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