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52 326 and 52 327, ensure that a gear segment of position and signalling unit drive in the extreme position
“open” or “closed” doesn’t hit the actuator case. A position unit of electric actuator Type No. 52 325 is not
equipped with the locking of cams using screws (Fig. 2). The cam’s position on the shaft is ensured only by
friction which has to be overcome when adjusting the cams. A design Type No. 52 325 has cams locked by
friction and central milled nut with contra-nut which must be loosened before adjusting and tightened prop-
erly again after adjusting.
Position transmitter
To adjust the potentiometer it is sufficient to set the actuator output shaft to any of the OPEN or CLOSED end
positions. In this way, the potentiometer is automatically preset. The automatic adjustment of the potentiometer is
usually provided already when the stop screws or the position-limit switches are adjusted.
Setting of current position transmitter CPT1AA
Before starting setting the current transmitter it is necessary to set the end-limit positions (torque or position
switches) of the actuator and connect them into the tripping circuit of the electric motor. In case of an external source
of feeding voltage, verification must be carried out that it does not exceed the maximum value 30 V DC (limit value
when CPT1 is still not damaged). Recommended value is 18 – 28 V DC.
Positive pole of the source is connected to the positive pole of the transmitter CPT1; a milli-ammeter of precision
at least 0.5 % connected into the circuit. The current loop must be earthed in one point. The figure does not show
the earthing that can be made at any point of the circuit.
1. Shift the output shaft into the position Closed. During closing, the current signal value should decrease.
If it increases release the transmitter body and, by turning of about 180°, shift to the descending part of
the outputcharacteristics. Set 4 mA by fine turning. Tighten the shim plates to secure the transmitter against
spontaneousturning.
2. Shift the output shaft to the position Open and set 20 mA using a potentiometer on the transmitter body.
The potentiometer has a range of 12 revolutions and it has no stops so that it cannot be damaged by furtherturning.
3. Once again verify the current value in the position Closed. If it has changed too much repeat the points 1. and 2.
If the required corrections are large this procedure should be repeated several times. After the setting, securethe
transmitter against turning and drip the screws with varnish.
4. Use a voltmeter to check the voltage on the CPT1 terminals. In order to keep linearity of the output signal
the voltage must not drop below 9 V, not even with off-take 20 mA. If this condition is not met it is necessary to
increase the feeding voltage (within the range of recommend values) or to decrease total resistance of the current
loop R.
Setting of current position transmitter DCPT
1. Set of end-limit positions
Before starting the setting, verification must be carried out that the end-limit positions are within the range
60° – 340° of revolution DCPT. Otherwise, after setting, an error arises (LED 2x).
1.1. Position “4 mA”
Set the drive into the required position and press the push-button “4” until LED blinks (about 2 s).
1.2. Position “20 mA”
Set the drive into the required position and press the push-button “20” until LED blinks (about 2 s).
2. Setting of sense of rotation
The sense of rotation is specified by viewing from the side of the panel DCPT.
2.1. Rotating anti-clockwise
Press the push-button “20”, then the push-button “4” and keep them depressed until LED blinks.
2.2. Rotating clockwise
Press the push-button “4”, then the push-button “20” and keep them depressed until LED blinks.
When the sense of rotation is changed the end-limit positions “4 mA” and “20 mA” remain valid but the work-
ing range (track DCPT) between these points is changed to a complement of the original working range. In this way,
the permitted working range can be exceeded (LED 2x) – it can be smaller than 60°.
3. Error messages
In case of an error the diode LED blinks an error code:
