14
Then loosen the screws of the transmitter contact plates so that the entire transmitter can be rotated. Turn the whole
transmitter to adjust current to 4 mA, and tighten adapter screws. Subsequently adjust actuator output shaft to
“open"
position. Use resistance trimmer in the front part of transmitter
(closer to the edge)
to set current to 20 mA. The trimmer’s
range is 12 revolutions and has no dead stops, so it cannot be damaged by overturning.
If correction by 20 mA was significant, repeat adjustments to 4 mA and 20 mA once again. Then, disconnect
the connected mA-meter. Do not turn the screw with varnish drops close to the centre. Properly tighten screws that lock
the transmitter adapters, and use varnish to protect them from release.
After adjustment, use voltmeter to verify voltage on transmitter terminals. It must lie between 9 and 16 V at the current
of 20 mA.
Note:
The transmitter’s curve has two branches – a decreasing branch relatively to “Z” position, or a rising branch relatively
to “Z” position. To select transmitter’s curve, turn the transmitter body.
d) Position unit
(Figure 9)
This unit secures switches PZ or PO to trip when the preset output shaft speed has been achieved. The unit’s rotary
motion is derived from the output shaft motion, by means drive wheel 62.
This wheel turns stepwise the aligned gears, which control cam 57
(60).
Cam turning to lever of switch PZ and PO will
make the switches change over.
Handling and adjustment
The unit can be set within the range from 2 to 250 revolutions
(1 – 100 revolutions in the case of type No. 52 026).
Adjustment procedure is as follows:
a) Once the actuator has been fixed to the valve, set valve to closed position using the actuator.
b) In this position, push tripping rod 58 in vertical direction and then turn it by 90 degrees in any direction.
b) Turn set screw 56 in
“Z”
arrow direction until the cam 57 pushes the spring of micro switch PZ 63.
d) Turn tripping rod 58 by 90°. Tripping rod will slip out again. If tripping rod fails to slip out, just very slightly turn screw 56 or 59.
e) Use the actuator to move the valve by the required number of revolutions to open position.
f) Again push tripping rod 58 in vertical direction and then turn it by 90 degrees in any direction.
g) Turn set screw 59 in
“O”
arrow direction until cam 60 pushes the spring of micro switch PO 61.
h) Turn tripping rod 58 by 90°. Tripping rod will slip out again. If tripping rod fails to slip out, just very slightly turn screw 59 or 56.
Note:
Stop turning screw 56, 59 at the moment of switching!
If, prior to adjustment, cams are in such a position as indicated on Figure 9 or if cam has already pushed the micro
switch button, it is advisable to proceed adjustment as follows:
After pushing and turning tripping rod 58, turn set screws 56 or 59 against arrows direction until the cam's tip leaves the
micro switch lever
(towards the closest set screw)
and the micro switch switches
(use suitable tester to make sure that
micro switch has switched).
Then turn set screw 56 or 59 in arrow direction to turn the cam’s tip back to the micro switch
lever until the micro switch switches again
(micro switch button)
is pressed. Now the micro switch has been adjusted. Then
slide tripping rod 58 out as described above.
Numbers in circles correspond to terminal numbers on the
terminal board.
Micro switches can be used only as single-circuit micro
switches. Two voltages with different values or phases must
not be led to the contacts of one micro switch.
55
56
63
20
17
14
16
15
19
21
18
62
61
57
58
59
60
Explanatory notes:
55 – Decade gear
56 – Set screw “Z”
57 – Tripping cam “Z”
58 – Tripping cam
59 – Set screw “O”
60 – Tripping cam “O”
61 – PO Switch
62 – Driving wheel
63 – PZ Switch
3
4
2
1
Micro switch
scheme
Fig. 9 –
Position unit
