QUESTION:
Which is the minimal required turn angle of the cam for a correct operation and a successful initialisation?
ANSWER:
That the SIPART PS2 can operate with sufficient resolution and specified accuracy,
the turn angle of the feed back cam, which conforms to a rotary section on the potentiometer track, should not fall below a minimal value.
The minimum turn angles are:
1. for the turn actuators 31°
2. for the travel actuators < 20mm ( gear switch on 33° ) 11°
3. for the travel actuators > 20mm ( gear switch on 90° ) 31°
Smaller turn angles will cause error messages
QUESTION:
Can SIPART PS2 also be used together with actuators which have a travel range > 130mm?
ANSWER:
If the travel of actuators is bigger than 130mm, in almost all cases it is possible to modify the mounting kit by lengthen the "long lever" (order number 6DR4004-8L ) or in special cases also the short lever of NAMUR-standard mounting kit ( order number 6DR4004-8V ).
This can be done by either cutting or sawing the lever into two parts and welding in a Stainless-steel strip ( material thickness should be similar to the lever material thickness ) between the both parts. The length of the new and elongated lever is calculated by the intercept theorems like following:
Ln : Hn = 94 : 130 which means:

Ln = 0,72 x Hn
meaning : Hn = New travel range in mm
Ln = New lever length in mm ( measured from the middle of the axis to the end of the slot )
QUESTION:
Can SIPART PS2 keep "FAIL IN PLACE" , if the setpoint signal ( 4-20mA ) vanishes?
ANSWER:
The best solution to keep the positioner " In Place" if the 4-20mA fails is to use SIPART PS2 in 3- or 4-wire application:
In this case SIPART PS2 continues with operation and can be stopped to keep in place by activating the binary input ( parameter no.42 on "Block Movement" by using binary input 1, or parameter no.43 on "Block Movement" by using Binary input 2 ). This activating of the binary input can be solved automatically, if the 4 - 20 mA signal fails, by connecting a 100 ohms resistance in series with the setpoint current circuit. One contact end of this 100 ohms resistance is connected to plug no.6 ( setpoint current input ), the other to the incoming current source. This connecting terminal ( must be realized by an additional plug ) of the incoming current source together with the 100 ohms resitance has additionally to be connected to plug no.9 (binary input 1 ) or plug no.21 ( binary input 2 ). Thus the binary input switches from "High" signal to "Low" state when the setpoint current ( 4-20mA ) vanishes. The positioner closes the pneumatic piezo valves and the actuator remains in its last position.
Please note:
24 V power supply shall not fail, otherwise the positioner will drive the actuator in end position.