6.5 Characteristic values
Safety standards (in accordance with IEC 61508)
Value
Probability of Dangerous Failure on Demand
(Probability of Dangerous Failure on Demand)
PFD
spec
8.89 · 10
-4
Assumed Test Interval (Assumed Test Interval)
T
i
1 a
Confidence Level (Confidence Level)
1-
á
95 %
Hardware Fault Tolerance(Hardware Fault Tolerance)
HFT
0
Diagnostic Coverage (Diagnostic Coverage)
DC
0
Type of Sub System (Type of Sub System)
Type A
Mode of Operation (Mode of Operation)
Low demand and
high demand
Degree of coverage of dangerous errors through the proof
test (Proof Test Coverage)
PTC
88 %
Assumed Demands per Year(Low Demand Mode)
(Assumed Demands per Year)
n
op
1 / a
Failure rate for dangerous errors not detected
(Lambda Dangerous Undetected)
ë
DU
1.01 · 10
-7
/ h
Mean time to failure (dangerous)
(Mean Time to Failure dangerous)
MTTF
D
1,126 a
Average probability of a dangerous failure on demand
(Low Demand Mode)
(Average Probability of Failure on Demand)
PFD
avg
(T
I
= 1 a)
4.44 · 10
-4
Assumed Demands per Year(High Demand Mode)
(Assumed Demands per Year)
n
op
8760 / a
Average frequency of a dangerous failure per hour
(High Demand Mode)
(Probability of dangerous failure per hour)
PFH
1.01 · 10
-7
/ h
Fig. 2
7
Product overview
7.1 Design
1
2
3
4
5
6
aB
9
aA
8
aJ
7
1
Mounting thread for limit switch or
position sensor
2
Transmission shaft (shaft groove
shows the process valve position –
here closed)
3
Mounting thread for pneumatic
NAMUR switching valve
4
Mounting thread for coding pin
5
Compressed air connection (4)
6
Mounting thread for pneumatic
NAMUR switching valve
7
Mounting thread for coding pin
8
Compressed air connection (2)
9
End-position adjustment on both
sides
aJ
Mounting thread for process valve
to ISO 5211
aA
Coupling for process valve
aB
Leakage slot
Fig. 3
Through the housing, a shaft is guided outward on both sides. Through this, the
reaction torque is transmitted to a process valve (
è
Fig. 3,
aA
) and, if applicable, a
limit switch or position sensor (
è
Fig. 3,
2
).
The end stops can be adjusted in the range ± 5° through the end-position adjust
ment on both sides (
è
Fig. 3,
9
).
7.2 Product variants and type code
Fig. 4 explains selected product characteristics that are necessary to un
derstand the instructions.
Description of the complete type code:
è
www.festo.com/catalogue.
Characteristic
Value
Description
Type
DFPD
Quarter turn actuator
System of units
–
N
Metric
Imperial
Size
10, 20, 40, 60, 80,
120, 160, 240, 300,
480
Swivel angle
90, 120, 135, 180
Swivel angle specification in [°]
Closing direction
L
R
Closes to the left
Closes to the right
Mode of operation
D
S
Double-acting
Single-acting
Spring configuration
–, 20, 25, 30, 35, 40,
45, 50, 55, 60
Not for double-acting drive,
for connection pressure with single-acting drive
Flange hole pattern 1
F03 , F04, F05, F07,
F10, F12
Flange hole pattern according to ISO 5211
Flange hole pattern 2
–, 07, 10, 12
Flange hole pattern according to ISO 5211
Temperature range
–, T4, T6
è
Technical data
Fig. 4
8
Function
The piston movement of the DPFD is converted through a rack & pinion kinematics
(rack and pinion principle) into a swivel motion of the transmission shaft.
– Single-acting quarter turn actuators: Return is
through spring force.
Fig. 5
– Double-acting quarter turn actuators: Through
pressurising and venting of the cylinder chambers,
the shaft turns back and forth.
Fig. 6
Symbol on the rating plate
Type
Mode of operation
Symbol
DFPD-...-RD-...
DFPD-...-LD-...
Double-acting
Closes to the right / left
DFPD-...-RS-...
Single-acting (spring return)
Closes to the right
DFPD-...-LS-...
Single-acting (spring return)
Closes to the left
Fig. 7
9
Transport and storage
Warning
Danger of crushing! Danger of shearing!
The product without accessories weighs up to 20.9 kg, depending on the
product version.
Body parts can be crushed or severed if the product falls.
Use appropriate load handling equipment.
When shipping used products: comply with all legal requirements for handling
hazardous substances and transporting dangerous goods.
For return to Festo
è
Chapter 2.
Remove all attachments.
Store the product in a cool, dry, UV-protected and corrosion-protected environ
ment. Ensure that storage times are kept to a minimum.