The output signal is linear between the taught end points, either rising or falling
according to the positions of the taught end points.
The electric output signal is applied to the electrical connection (
è
circuit diagram
in Fig.13). This signal can be conveyed to higher−level systems for ev aluation.
The following figures show examples of possible signal curves.
Example 1:
end point 1 (MIN, 4 mA) at an angle w of 0°;
end point 2 (MAX, 20 mA) at an angle w of 90°
Fig.4: Possible cur ve after teaching procedure example 1
Example 2:
end point 1 (MIN, 4 mA) at an angle w of 90°;
end point 2 (MAX, 20 mA) at an angle w of 0°
Fig.5: Possible cur ve after teaching procedure example 2
Analogue
signal
Assignment
0 mA
No valid signal (e.g. wire break)
2 mA
Shaft out of measuring range
1)
4 mA
Taught value MIN
2)
reached
4)
20 mA
Taught value MAX
3)
reached
4)
>4 mA
...
<20 mA
Shaft within the measuring range at the corresponding position
1)
Value < MIN position hysteresis or > MAX + position hysteresis
2)
Is assigned to the current position upon the first teach signal
3)
Is assigned to the current position upon the second teach signal
4)
Position hysteresis (buffer): 7.2 °
Fig.6
4
Application
The sensor box SRAP is intended to be used for detecting, transmitting and dis
playing the position of quarter−turn actuators in process automation systems. The
sensor box detects the actuation position of the driven process valve.
It is suitable for use with quarter−turn actuators which actuate butterfly valves and
ball valves (process valves) with slow movements and low cycles in media−filled
pipelines.
The sensor box is optimally designed for use with Festo’s quarter−turn actuator
DFPB. It can be mounted directly on the DFPB with a suitable coupling (
Fig.7
1
),
without mechanical adapter bridges. It can also be used with other quarter−turn
actuators from Festo or from other manufacturers if these have a mechanical inter
face in accordance with VDI/VDE Guideline 3845 and suitable mechanical adapter
bridges are available (
è
www.festo.com/catalogue).
The maximum sensing range for the sensor box is 270°.
The device is designed for use in the process industries and in industrial applica
tions.
5
Transport and storage
Ensure the following storage conditions:
Short storage periods in cool, dry, shaded and corrosion−protected locations.
6
Requirements for product use
Fitting and commissioning is to be carried out only by qualified personnel in ac
cordance with the operating instructions.
Warning
Pinch point! Body parts can be injured by the rotating shaft.
· Vent the system before mounting or removing.
· Ensure that no one can put their hands near any moving parts.
It must not be possible to touch the shaft until the system is unpressurized.
Note
Improper handling can result in malfunctions.
· Make sure that all the instructions in this chapter are observed. The product
will then function correctly and reliably.
· Compare the maximum values specified in these operating instructions with
your actual application (e.g. currents, voltages, torques, temperatures). The
product can only be used in accordance with the relevant safety guidelines if the
maximum load limits are observed.
· All applicable national and international regulations must be complied with.
· Remove the packaging. The packing is intended for recycling (except for: oiled
paper = general waste).
· Take into consideration the ambient conditions at the location of use. Corrosive
environments reduce the service life of the product.
· Use the product only in process industries and in industrial applications, only as
intended, in its original condition without unauthorized modifications, and in
perfect technical condition. Only the conversions and modifications described in
this documentation are permitted.
· The product is not a safety component and must only be used as designated.
· If commercially−available valves are connected, the specified limits for pres
sures, temperatures, electrical data, torques, etc. must not be exceeded.
· Please select the appropriate accessories, for example adapter bridges, coup
lings and electric cable, from our catalogue www.festo.com/catalogue.
7
Installation
Caution
Uncontrolled movements of the drive can cause damage during mounting.
· Before installing the sensor box, make sure that the compressed air and
power supply are switched off and the quarter−turn actuator is unpressurized.
· Lock out the system to prevent it being restarted.
7.1 Mechanical installation
· For use with the
DFPB, use a suitable
mechanical coupling
1
. When using
other quarter−turn
actuators, you will
need suitable
adapter bridges
2
(see accessories in
è
catalogue
www.festo.com/
catalogue).
· Mount and assemble
the sensor box so
that it works in the
manner desired.
Fig.7
1
2
For mounting on quarter−turn actuators, the sensor box has a pattern of mounting
holes in accordance with VDI/VDE Guideline 3845 (
è
catalogue www.festo.com/
catalogue).
The four mounting screws (
8
) are already captive−attached in the base
plate. To mount the sensor box, you must remove the housing cover (
1
)
and the 9−pin terminal strip (
aA
).
