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VP500-TF2Z495EN-A
2 Specifications - continued
V1
V3
V4
V2
Figure 4. External pilot, Rockwell switch variant
2.8 Soft start specification and operating principle
2.8.1 Operating principle
• In a safety related application, the machine safety system will energise
the safety valves (V3 and V4 in Figure 4) when the machine is safe to
operate.
When both valves are energised air will flow into the
protected system via port 2 (A). The flow is initially limited by needle
valve V1 and pressure in the protected system will remain low as the
system fills or actuators move slowly. The pressure will eventually rise
as the system becomes full or the actuators stop moving. As P2
pressure increases (see Figure 5) valve V2 switches and valve V1 is
by-passed. In this condition air will flow into the protected system
according to the figures given in section 2.3.
• When either of the valves V3 or V4 are de-energised the protected
system is vented to atmosphere. When the protected system pressure
drops below P2 (see Figure 5) valve V2 returns to its spring state with
V1 limiting the flow to V3 and V4.
0.5
0.4
0.3
0.2
0.1
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Inlet pressure MPa P1
Figure 5. Switching pressure (Close → Open) of soft start-up valve V2
2.8.2 Soft start flow
The restricted flow is set by V1. This can be adjusted or there are product
options with fixed orifices.
Variant
Soft start flow
(see section 4)
VP500
VP700
Variable
(See fig. 6)
10
Ø1 mm
Ø1 mm
15
Ø1.5 mm
Ø1.5 mm
20
-
Ø2 mm
Table 7. Soft start flow options
2 Specifications - continued
Number of rotations of needle valve
Figure 6. Needle valve flow characteristics (Use this graph as a guide only)
2.9 Declaration of Conformity
1
Figure 7.
2 Specifications - continued
Figure 8.
Figure 9.
2 Specifications - continued
2.10 Base mounted valve identification
VP#44 valves are marked with mounting arrows, which are designed to
point towards a mating arrow on the sub plate.
2.11 Batch code
The batch code indicated in the product label translates to construction
year / month according to the following table (eg. "CQ = Mar 2024):
Construction
Production batch codes
Year / Month Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
2024
Co
CP
CQ
CR
CS
CT
CU
CV
CW
CX
2025
Do
DP
DQ
DR
DS
DT
DU
DV
DW
DX
...
...
...
...
...
...
...
...
...
...
...
2027
Fo
FP
FQ
FR
FS
FT
FU
FV
FW
FX
Table 8.
2.12 Safety system
2.12.1 Timing diagram
Figure 10. Diagram of a duplex valve
Note: The monitor switches are Normally Closed, i.e. closed when the
valve solenoids are de-energised. The monitor signals are therefore
shown 'High' when the valve is de-energised.
2.12.2 VP544 / VP744 valve and switch response
• The valve response time ON (T1) depends on the supply pressure and
the volume of the protected system, and the soft start operation (see
2.8). T1 times are not related to the safety function.
• The valve response time OFF (T2) depends on the volume (V) and the
flow capacity of the protected system. It is defined as the time interval
in which the pressure in a test volume connected to an outlet port of
the valve reduces from 0.63 MPa to 0.05 MPa in response to a change
in the control signal to that valve. Refer to tables below for indicative
values under SMC conditions.
• The ON response time of the limit switch (T3) is shown in the table
below.
• The OFF response time of the limit switch (T4) is shown in the table
below.
Caution
• Response time values are for reference only and it is the system
integrator's responsibility to obtain the actual values.
Volume
Valve OFF response /
Switch Response
/ litre
T2, ms
T3, ms
T4, ms
3
1110
155
10
3560
30
(250 for high
20
7060
pressure type)
Table 9. VP544 response time
Volume
Valve OFF response /
Switch Response
/ litre
T2, ms
T3, ms
T4, ms
3
930
280
10
2750
40
(320 for high
pressure type)
20
5350
Table 10. VP744 response time
Caution
• Response times are based on tests under SMC conditions and are not
guaranteed. Always observe the terms of 2.12.3.
• Exhaust times will increase on the duplex valves when only one
channel is functioning in a fault condition.
Page 2 of 5
Cy
CZ
Dy
DZ
...
...
Fy
FZ
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