Siemens ACVATIX SKB Series User manual

CM1N4564en
Smart Infrastructure
2023-10-17
ACVATIX™
Electro-hydraulic actuators for valves
SKB..
with a 20 mm stroke
●SKB32.. Operating voltage AC 230 V, 3-position control signal
●SKB82.. Operating voltage AC 24 V, 3-position control signal
●SKB6.. Operating voltage AC 24 V
–Control signal DC 0...10 V, 4...20 mA or 0...1000 Ω
–SKB62/MO RS-485 for Modbus RTU communication
–Selection of flow characteristic, position feedback, stroke calibration, LED
status indication, override control
–SKB62UA with selection of direction of operation, stroke limit control,
sequence control with adjustable start point and operation range, operation of
frost protection monitors QAF21.. and QAF61..
●Positioning force 2800 N
●Versions with or without spring-return function
●For direct mounting on valves; no adjustments required
●Manual adjuster and position indicator
●Optional functions with auxiliary switches, potentiometer, stem heater and
mechanical stroke inverter
●SKB..U are UL-approved

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CM1N4564en
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Use
For the operation of Siemens 2-port and 3-port valves of the types VVF.., VVG.., VXF.. and
VXG.. with a 20 mm stroke as control and safety shut-off valves in heating, ventilation and
air conditioning plants.
Technical design
Principle of electro-hydraulic actuators
1
Manual adjuster
2
Pressure cylinder
3
Suction chamber
4
Return spring
5
Solenoid valve
6
Hydraulic pump
7
Piston
8
Pressure chamber
9
Position indicator (0 to 1)
10
Coupling
11
Valve stem
12
Plug
Valve closed
Valve opened
Opening the
valve
The hydraulic pump [6] forces oil from the suction chamber [3] to the
pressure chamber [8], thereby moving the pressure cylinder [2] downwards.
The valve stem [11] retracts and the valve opens. Simultaneously, the return
spring [4] is compressed.
Closing the
valve
Activating the solenoid valve [5] allows the oil in the pressure chamber to
flow back into the suction chamber. The compressed return spring moves
the pressure cylinder upwards. The valve stem extends and the valve
closes.
Manual
operation
mode
For manual operation, swing out the crank so that the display window
becomes visible. By rotating the crank clockwise, the pressure cylinder is
moved downwards. The display window shows the engagement bar and/or
the scale dial with stroke indication.
In the manual operation mode, the positioning signals Y and Z can further
open the valve but cannot move to the 0 % stroke position of the valve. To
retain the manually set position, switch off the power supply or disconnect
the positioning signals Y and Z. The crank remains swung out and in the
display window the red indicator dial remains visible.
Note:
When setting the controller to manual operation for a longer
period of time, we recommend adjusting the actuator with the
manual adjuster to the desired position. This guarantees that
the actuator remains in this position for that period of time.
Attention: Do not forget to switch back to automatic operation
after the controller is set back to automatic control.

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CM1N4564en
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2023-10-17
Automatic
operation
mode
For automatic operation, turn the manual adjuster clockwise to the end stop.
The pressure cylinder moves upwards to the 0% stroke position of the valve.
In the display window, the read scale disappears. Afterwards, swing the
crank closed.
Minimal
volumetric
flow
The actuator can be manually adjusted to a stroke position > 0%, allowing
its use in applications requiring a constant minimal volumetric flow.
SKB32..
SKB82..
3-position
control signal
The actuator is controlled by a 3-position signal either via terminals Y1 or Y2
and generates the desired stroke, which is transferred to the valve stem:
●Voltage on Y1:
Piston extends
Valve opens
●Voltage on Y2:
Piston retracts
Valve closes
●No voltage on Y1 and Y2:
Piston and valve stem remain in the
respective position
SKB62..
SKB60
Y positioning
signal
DC 0...10 V
and/or
0...1000 Ω,
DC 4...20 mA
The actuator is either controlled via terminal Y or override control Z. The
positioning signals generate the desired stroke by means of the above
described principle of operation, which is transferred to the valve stem:
●Signal Y increasing:
Piston extends
Valve opens
●Signal Y decreasing:
Piston retracts
Valve closes
●Signal Y constant:
Piston and valve stem remain in the
respective position
●Override control Z:
See Functions [➙8]
Frost
protection
monitor
Frost
protection
thermostat
A frost protection thermostat can be connected to the SKB6.. actuator.
The added signals from the frost protection monitors QAF21.. and QAF61..
require the use of SKB62UA actuators. Notes on special programming of
the electronics are described under Electronics [➙5].
Connection diagrams for operation with frost protection thermostat or frost
protection monitor can be found under Connection diagrams [➙26].

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CM1N4564en
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Electronics
SKB60 1)
1
Connection terminals
2
DIL switches
3
LED status indication
4
Stroke calibration
1)
From version ..L onward
DIL switches
Direction of operation
Fail-in-place (behaviour in
case of control signal loss)
**
Positioning signal Y
Positioning feedback U
Flow characteristic
ON
Reverse acting
Stops at current
position
DC 4...20 mA
lin = linear
OFF *
Direct acting
Closes
DC 0...10 V
log = equal
percentage
Relationship between
positioning signal Y and
volumetric flow
*
Factory setting: all switches OFF
**
Only considered when DIL switch 3 ON
(control signal = DC 4…20 mA)
SKB60 2), SKB62..
1
Connection terminals
2
DIL switches
3
LED status indication
4
Stroke calibration
2)
Up to and including version ..K

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CM1N4564en
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2023-10-17
DIL switches
Positioning signal Y
Positioning feedback U
Flow characteristic
ON
DC 4...20 mA
lin = linear
OFF *
DC 0...10 V
log = equal percentage
Relationship between
positioning signal Y and
volumetric flow
*
Factory setting: all switches OFF
SKB62UA
1
Connection terminals
2
DIL switches
3
LED status indication
4
Stroke calibration
5
Rotary switch UP
(factory setting 0)
6
Rotary switch LO
DIL switches
Direction of operation
Sequence control or stroke
limit control
Positioning signal Y
Positioning feedback U
Flow characteristic
ON
Reverse acting
Sequence control
Signal addition
QAF21../QAF61..
DC 4...20 mA
lin = linear
OFF *
Direct acting
Stroke limit control
DC 0...10 V
log = equal
percentage
Relationship between
positioning signal Y and
volumetric flow
*
Factory setting: all switches OFF

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CM1N4564en
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SKB62/MO
The Modbus converter is designed for analog control at 0...10 V.
Keep the analog signal setting on the actuator as is (switch 1 to OFF); adjustment not
permitted.
The actuators are factory configured for equal-percentage characteristic.
DIL switch (internal actuator characteristic changeover) to "log" (switch 2 to OFF).
Functions
Spring-return function
The SKB32.51, SKB82.51.. and SKB62.. actuators, which feature a spring-return function,
incorporate a solenoid valve which opens if the control signal or power fails. The return
spring causes the actuator to move to the 0% stroke position and closes the valve.
Calibration
SKB60, SKB62.., SKB62/MO
In order to determine the stroke positions 0% and 100% in the valve, calibration is required
on initial commissioning.
Mechanical coupling of the actuator SKB6.. with a Siemens valve.
Actuator must bin in „Automatic operation mode“ enabling stroke calibration
to capture the effective 0% and 100% values.
AC 24 V power supply applied.
Housing cover removed.
1. Short-circuit contacts in calibration slot (e.g. with a
screwdriver) and trigger calibration process.
2. Actuator moves to 0% stroke position [1].
Valve closes.
3. Actuator moves to 100% stroke position [2].
Valve opens.
Measured values are stored.
LED flashes grün, positioning
feedback U inactive
Normal operation:
Actuator moves to the position [3] as indicated by signals
Y or Z.
LED is lit green permanently, positioning feedback U
active, values correspond to the actual positions.
A red lit LED on the actuator indicates a calibration error.

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CM1N4564en
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The LED on the SKB62/MO cable adapter flashes red during the calibration, as the
positioning signal Y and the positioning feedback U do not correspond anymore. This is
interpreted as a blockage and thus indicated as an error.
If necessary, the calibration can be repeated any number of times.
LED indication of operational status
SKB60, SKB62.., SKB62/MO
The dual-colored LED indicating the operational status is visible when the cover is removed.
LED
indication
Function
Remarks, troubleshooting
Lit green
Normal operation
Automatic operation; everything o.k.
Flashing green
Stroke calibration in progress
Wait until calibration is finished
(LED stops flashing, will be lit green or red)
Lit red
Faulty stroke calibration
Check mounting; restart stroke calibration (by short-circuiting
calibration slot)
Internal error
Replace electronics
Flashing red
Inner valve jammed
Troubleshoot, check valve, restart stroke calibration
Dark
No power supply
Check mains network, check wiring
Electronics faulty
Replace electronics
As a general rule, the LED can only assume the states shown above –continuously lit red or
green, flashing red or green, or off/dark.

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Override control Z
SKB60, SKB62..
The override control input Z can be operated in the following modes of operation:
Z-mode
No function
Fully open
Closed
Override with 0…1000 Ω
Signal addition
SKB62UA only
Connections
Transfer
Equal percentage or
linear
Equal percentage or linear
●Z-contact not
connected
●Z-contact directly
connected to G
●Z-contact directly
connected to G0
●Z-contact connected to
M via resistor R
●Starting position at 50 Ω
End position at 900 Ω
●Z-contact
connected to R of
frost protection
monitor QAF21..
or QAF61..
●Valve stroke follows
Y-input
●Y-input has no effect
●Valve stroke
follows Y and
R(Z) signal
Shown operation modes are based on the factory setting “direct acting”.
Y-input has no effect in Z-mode.
Selection of direction of operation
SKB60 (from version ..L), SKB62UA
●With normally-closed valves, “direct acting” means that with a signal input of 0 V, the
valve closes (applies to all Siemens valves listed under Equipment combinations [➙12]).
●With normally-open valves, “direct acting” means that with a signal input of 0 V, the valve
is open.
Direct acting
Reverse acting
Stroke
Input
DC 0...10 V
DC 4...20 mA
0...1000 Ω
Input
DC 0...10 V
DC 4...20 mA
0...1000 Ω
The mechanical spring-return function is not affected by the direction of operation selected.

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Stroke limit control and sequence control
SKB62UA
Setting the stroke limit control
Setting the sequence control
The rotary switches LO and UP can be
used to apply a lower and upper limit to the
stroke in increments of 3%, up to a
maximum of 45%.
The rotary switches LO and UP can be
used to determine the start point or the
operating range of a sequence.
Position
of LO
Lower stroke
limit
Position
of UP
Upper stroke
limit
Position
of LO
Sequence
control
start point
Position
of UP
Sequence
control
operating range
0
0 %
0
100 %
0
0 V
0
10 V
1
3 %
1
97 %
1
1 V
1
10 V *
2
6 %
2
94 %
2
2 V
2
10 V **
3
9 %
3
91 %
3
3 V
3
3 V ***
4
12 %
4
88 %
4
4 V
4
4 V
5
15 %
5
85 %
5
5 V
5
5 V
6
18 %
6
82 %
6
6 V
6
6 V
7
21 %
7
79 %
7
7 V
7
7 V
8
24 %
8
76 %
8
8 V
8
8 V
9
27 %
9
73 %
9
9 V
9
9 V
A
30 %
A
70 %
A
10 V
A
10 V
B
33 %
B
67 %
B
11 V
B
11 V
C
36 %
C
64 %
C
12 V
C
12 V
D
39 %
D
61 %
D
13 V
D
13 V
E
42 %
E
58 %
E
14 V
E
14 V
F
45 %
F
55 %
F
15 V
F
15 V
*
Operating range of QAF21.. (see below)
**
Operating range of QAF61.. (see below)
***
The smallest adjustment possible is 3 V; control with 0...30 V is only possible via Y.
Stroke control with QAF21.. / QAF61.. signal addition
SKB62UA
Setting the signal addition
The operating range of the frost protection monitor QAF21.. or
QAF61.. can be defined with rotary switches LO and UP.
Position of LO
Sequence control
start point
Position of UP
QAF21.. / QAF61..
operating range
0
→
1
QAF21..
0
→
2
QAF61..

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Type summary
Type
Operating
voltage
Positioning
signal
Spring-return
Positioning time
Function
Time
Opening
Closing
SKB32.50 1)
-
AC 230 V
3-position
-
-
120 s
120 s
SKB32.50/F 1), 3)
SKB32.51 1)
yes
10 s
SKB32.51/F 1), 3)
SKB82.50 1)
AC 24 V
-
-
SKB82.50U 2)
SKB82.51 1)
yes
10 s
SKB82.51U 2)
SKB60 1), 4)
Standard
electronics
DC 0...10 V
4...20 mA
0...1000 Ω
-
-
10 s
SKB62 1)
yes
10 s
SKB62/F 1), 3)
SKB62U 2)
SKB62UA 2), 5)
Enhanced
electronics
SKB62/MO 2)
S55195-A127
Standard
electronics
Modbus RTU
1)
Approbation: CE
2)
Approbation: CE, UL
3)
Only available in France
4)
Enhanced functions (from version ..L): Direction of operation, fail-in-place
5)
Enhanced functions: Direction of operation, stroke control limit, sequence control, signal addition
Scope of delivery
The actuator, valve and accessories are supplied in separate packaging and not assembled
prior to delivery.
Accessories / spare parts
Accessories
Type
Auxiliary
switch
Double
auxiliary
switch
Potentiometer
1000 Ω
Stem heater
AC 24 V
Mechanical
stroke inverter
ASC1.6
ASC9.3
ASZ7.3
ASZ6.6
(S55845-Z108)
ASK51
Max. 2
SKB32..
-
Max.1
Max.1
Max.1
Max.1
SKB82
SKB6..
Max.1
-
-