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VP-SMY116EN
2 Specifications - continued
2.7.3 SS type
Figure 6. Internal pilot (Rockwell switch variant shown for reference)
Figure 7. External pilot (Rockwell switch variant shown for reference)
2.7.4 DS type
Figure 8. Internal pilot (Rockwell switch variant shown for reference)
V1
V3
V4
V2
Figure 9. External pilot (Rockwell switch variant shown for reference)
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 9) 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 10) 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.
2 Specifications - continued
• 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 valve V2 returns to its spring returned state with V1
limiting the flow to V3 and V4.
0.4
0.3
0.2
0.1
0
0.2
0.3
0.4
0.5
0.6
Inlet pressure MPa P1
Figure 10. Switching pressure (Close → Open) of soft start-up valve V2
2.8.2 Soft start flow
The adjustable flow restriction is set by V1, see Figure 11 and 12.
Needle rotations (Number of turns)
Figure 11. Needle valve flow characteristics VP546(K)-SS/DS
(Use this graph as a guide only)
Needle rotations (Number of turns)
Figure 12. Needle valve flow characteristics VP746(K)-SS/DS
(Use this graph as a guide only)
2 Specifications - continued
2.9 Declaration of conformity
0.7
2 Specifications - continued
2.10 Batch code
The batch code indicated in the product label translates to construction
year / month according to the following table (eg. "ZQ = Mar 2021):
Construction
Production batch codes
Year / Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
2021
Zo
ZP
ZQ
ZR
ZS
ZT
ZU
ZV
ZW
ZX
2022
Ao
AP
AQ
AR
AS
AT
AU
AV
AW
AX
...
...
...
...
...
...
...
...
...
...
...
2024
Co
CP
CQ
CR
CS
CT
CU
CV
CW
CX
Table 6.
2.11 Safety system
2.11.1 Timing diagram
Figure 13. Diagram for 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.
2.11.2 VP546(K) / VP746(K) valve and switch response
• The valve response time ON (T1) depends on the supply pressure, 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 table 7 and 8 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
Switch Response
/ litre
response / T2, ms
T3, ms
T4, ms
3
1110
155
10
3560
30
(250 for K type)
20
7060
Table 7. VP546(K) response time
Volume
Valve OFF response
Switch Response
/ litre
/ T2, ms
T3, ms
T4, ms
3
930
280
10
2750
40
(350 for K type)
20
5350
Table 8. VP746(K) response time
Caution
• Response times are based on tests under SMC conditions and are not
guaranteed. Always observe the terms of 2.11.3.
• Exhaust times will increase on the duplex valves when only one
channel is functioning in a fault condition.
Page 2 of 4
Nov
Dec
Zy
ZZ
Ay
yZ
...
...
Cy
CZ
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