Linear drive
DFPI−...−...−ND2P−E−P
Festo AG & Co. KG
Postfach
D−73726 Esslingen
++49/711/347−0
www.festo.com
(en) Operating instructions
740536
0811NH
Original: de
1
Operating elements and connections using the DFPI−100−... as an example
2
1
4
3
9
aJ
5
6
7
8
6
6
6
aA
aB
1
Mounting thread for adapter
(on rear,
è
Fig.4)
2
Piston rod with mounting thread
for coupling
3
Slot for proximity sensor
4
Shown without flange receptacle
5
Electrical connection
6
Thread for mounting the flange
receptacle
7
Earth terminal; position depends
on piston diameter of the drive
8
Pneumatic connection 4
(advance piston rod)
9
Pneumatic connection 2
(retract piston rod)
aJ
Electric cable
(displacement encoder)
aA
Flange receptacle; type depends
on piston diameter of the drive
aB
Cylinder barrel; version depends
on piston diameter of the drive
Fig.1
2
Structure
The DFPI−...−...−ND2P−E−P is an electropneumatic linear drive consisting of:
a double−acting pneumatic cylinder with
integrated displacement encoder (potentiometer) for determining the actual
position.
The displacement encoder supplies an analogue signal proportional to the
displacement in the form of a voltage (voltage divider).
If necessary, proximity switches can be installed in the slots (
è
Fig.1
3
) in order
to provide binary interrogation of positions.
The electric and pneumatic connections are protected against external mechanical
influences by a rugged flange receptacle.
Characteristics
Type code
Description
Type
DFPI
Double−acting pneumatic drive for process
automation with integrated displacement encoder
Size of servo drive
100
125
160
200
250
320
Piston diameter can be selected in steps;
dimensions in [mm]
Stroke
Ū
(40
Ū
990)
Stroke length freely selectable in the range
from 40 to 990; dimension in [mm]
Cushioning
N
No cushioning
Displacement encoder
D2
Integrated analogue displacement encoder
Method of measurement
P
Potentiometer
Controller attachment
position
E
External (no controller integrated)
Connection type
P
Protected pneumatic connections
Fig.2
The following characteristics of the linear drive are dependent on the piston
diameter, and may differ from the depiction in Fig.1:
Position of the earth terminal (
è
identification on product)
Shape of the cylinder barrel
Shape of the flange receptacle
In addition, for linear drives with a piston diameter
ţ
200mm the compressed air
supplied from one side is fed via an unprotected line parallel to the cylinder barrel.
Tie rod screws are used to mount the cylinder end cap.
For linear drives with a piston diameter
Ţ
200mm the compressed air is fed inter
nally. The cylinder end caps are screwed to the housing.
3
Function
Pressurising and depressurising of the
cylinder chamber causes the piston rod
connected to the piston to move to and
fro. The integrated displacement
encoder transmits the current position
to the higher−level system as an
analogue signal.
Fig.3
The processing valve (e.g. slide plate, penstock shut−off valve) , which is connected
via a coupling, opens or closes depending on the motion of the piston rod. The
cross−sectional area of the piston rod differences of force between forward stroke
and return stroke (
è
www.festo.com/catalogue).
4
Application
The designated use of the DFPI linear drive is to drive linearly actuated processing
valves in process systems for example slide valve actuators and penstock
shut−off valves. It is suitable for use in the process industry in the area of:
water,
sewage,
industrial process water,
silage and
bulk goods technology.
The stroke length of the drive is generally at least equal to the nominal diameter of
the valves and fittings, so that the slide valve actuator can be opened and closed
completely using the DFPI.
The product is tailored to the requirements of the process industry
(
è
catalogue www.festo.com/catalogue).
