HYDRAULIC SERVO VALVES – S4 PRO

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Hydraulic Servo Valves – S4 Pro

As the smallest direct drive valve in the world, the S4 Pro is a true game-changer. With its miniature port circle of 0.48 in (12.2 mm) and weight of less than 0.65lbs (300g), it’s perfectly suited for applications where space is limited but performance is paramount.

From demanding industrial settings to cutting-edge robotics and motorsport applications, the S4 Pro excels. Delivering superior performance, dynamics, and reliability in an ultra-compact package, it introduces a new era of control and productivity with the Domin S4 Pro series.

Available on S01 port pattern as standard.

Key Specs:

Hysteresis: <1%
Leakage: <0.12 gpm (<0.45 l/min)
Mass: 0.64lbs (290g)
Frequency Response: >200Hz
Rated Flow: 0.2-5gpm (0.5-18 l/min)
Response Time: <3 ms

Key Features:

Integrated electronics with spool position feedback
Rated flow rate of up to 5gpm (18 l/min)
Bandwidth of over 200 Hz
Low power consumption of less than 2 W
Miniature footprint (ISO 10372 size 01)
Low weight of 0.64lbs (290 g)

Standard Modification Options:

6 different control methods
2 different hydraulic fluids
3 choices of seal material
4 choices of connector

Technical Data

Design		Direct Drive Servo Valve
Actuation		Rotary-Rotary
Size		Miniature
Mounting Interface		ISO 10372-01-01
Ambient Temperature	ºC (ºF)	-20 to +60 (-4 to +140)
Mass	kg (lb)	0.29 (0.64)
Vibration Resistance	g	35, 3 axes
Shock Resistance	g	50

Max. Operating Pressure (P, A, B, T)	Bar (psi)	350 (5,000)
Fluid		Hydraulic Oil DIN 51524-535
Fluid Temperature	ºC (ºF)	-20 to +80 (-5 to +175)
Viscosity	cSt	5 to 500
Rated Flow	l/min (US gal / min)	0.5 to 6 (0.2 to 1.6) / 6 to 11 (1.6 to 2.9) / 11 to 18 (2.9 to 4.8)
Flow Maximum	l/min (US gal / min)	1.4 to 12 (0.4 to 3.2) / 12 to 22 (3.2 to 5.8) / 22 to 36 (5.8 to 9.6)
Leakage at 100 bar	l/min (US gal / min)	<0.2 (0.05) / <0.45 (0.12) / <0.45 (0.12)
Filtration		ISO 4406 (1999) 18/16/13

Response Time at 100% Step Input	ms	<3
Frequency Response (-3dB gain, ±25% signal)	Hz	>200
Frequency Response (-90deg phase, ±25% signal)	Hz	>110
Hysteresis	%	<1
Threshold	%	<1
Null Shift	%	<1

View performance graphs for the S4 Pro Domin Servo Valve below including Step Response, Flow vs Command, Frequency Response, and Pressure Gain:

Ratings of the valve electronics vary based on selected command input. Note that input ranges of Code E (±5 mA) are unavailable for S4 Pro.

Absolute Maximum Ratings*		Min.	Typ.	Max.
Supply Voltage	V	0	–	30
Differential Input Signal	V	-10.5	–	10.5
Input Signal Common Mode Offset	V	-10	–	10

Normal Operating Conditions		Min.	Typ.	Max.
Supply Voltage	V	22	24	30
Peak Current Consumption**	A	–	–	3.3
Differential Input Signals	V	-10	–	10
Input Impedance	KΩ	200	–	–

Absolute Maximum Ratings*		Min.	Typ.	Max.
Supply Voltage	V	0	–	30
Differential Input Signal	mA	-25	–	25
Input Signal Common Mode Offset	V	-10	–	10

Normal Operating Conditions		Min.	Typ.	Max.
Supply Voltage	V	22	24	30
Peak Current Consumption**	A	–	–	3.3
Differential Input Signals	mA	20	–	20
Input Impedance***	Ω	–	392	–

Absolute Maximum Ratings*		Min.	Typ.	Max.
Supply Voltage	V	0	–	30
Differential Input Signal	mA	-25	–	25
Input Signal Common Mode Offset	V	-10	–	10

Normal Operating Conditions		Min.	Typ.	Max.
Supply Voltage**	V	22	24	30
Peak Current Consumption	A	–	–	3.3
Differential Input Signals	mA	4	–	20
Differential Input Signals for drive off****	mA	-20	–	2
Input Impedance***	Ω	–	392	–

Absolute Maximum Ratings*		Min.	Typ.	Max.
Supply Voltage	V	0	–	30
Differential Input Signal	mA	-5.5	–	5.5
Input Signal Common Mode Offset	V	-5	–	5

Normal Operating Conditions		Min.	Typ.	Max.
Supply Voltage	V	22	24	30
Peak Current Consumption**	A	–	–	3.3
Differential Input Signals	mA	-5	–	5
Input Impedance	KΩ	200	–	–

* Conditions outside of the absolute maximum ratings may cause permanent damage to the valve. Operation of the product outside of the nominal operating conditions is not guaranteed and may affect product reliability.

** The valve supply must be protected with a 4 AT fuse or equivalent overcurrent protection device.

*** Valves with a current command signal use a 0.1% tolerance shunt resistor to measure demand current.

**** For 4 to 20mA command signal, a current in this range will disable the motor drive until a current outside this range is received at the command input.

Valves can be provided with an enable function. This allows the valve to be enabled or disabled by varying the voltage into the enable pin. Note that valves with code C command type can also be enabled or disabled using the command signal; see the corresponding table for further details.

Normal Operating Conditions		Min.	Typ.	Max.
Voltage for Drive Enable	V	9	–	28
Voltage for Drive Disable	V	0	–	5
Input Impedance	Ω	50	–	–

Please note pin orientation. Not to scale. Flying leads that terminate in bare wires do not have associated diagrams. In these cases, please refer to the wire color to determinate the correct pin out.

Type: Flying Lead (300 mm length)
Termination: Bare Wires

Wire Color	Function	Desc.
White	Supply 0 V	0 V
Black	Supply +	+24 V
Green	Input – (Ground Ref)	Differential Input Signal, –
Red	Input +	Differential Input Signal, +

Type: Case Mounted
Termination: Connector according to EN 175201-804/MIL 5015 equivalent, shell size 14

Pin	Function	Desc.
A	Supply +	+24 V
B	Supply 0 V	0 V
C	Output – Enable Input	Output 0 V Reference Drive Enable Input*
D	Input +	Differential Input, +
E	Input –	Differential Input, –
F	Output +	Output Signal
G	Earth	–

* When the enable function is selected, the function of pin C is the enable input. This replaces the standard pin function.

Type: Case Mounted
Termination: Connector according to EN 175201-804/MIL 5015 equivalent, shell size 14
Number of Contacts: 4

Pin	Function	Desc.
A	Supply +	+24 V
B	Input +	Differential Input, +
C	Input –	Differential Input, –
D	Supply 0 V	0 V

Type: Flying Lead
Termination: Winchester™ G4-20P

Pin	Function	Desc.
A	Supply 0 v	0 v
B	Supply +	+24 V
C	Input – (Ground Ref)	Differential Input, –
D	Input +	Differential Input, +

Unit Dimensions – Connector Code G and B4

Unit Dimensions – Connector Code E and E4

Nominal dimensions are displayed in mm. Bracketed dimensions are in inches. Not to scale.

Mounting Surface Pattern Dimensions

	Dia Ø mm	X Position mm	Y Position mm
F1	M4	0	0
F2	M4	23.8	0
F3	M4	23.8	26.2
F4	M4	0	26.2
P	3.8	11.9	19.2
A	3.8	18.0	13.1
B	3.8	5.8	13.1
T	3.8	11.9	7.0

Bolts (F1, F2, F3, F4)

Type: M4 x 55 DIN EN ISO 4762-10.9
Required Torque: 2.5 Nm (1.8 ft-lbf)

O-Rings (P, A, B, T)

Type: 4.47 x Ø 1.78 (ISO 3601-1-008)
Material: NBR, EPDM or Viton, 70 Shore A
Hardness: 70 Shore A

Standards Compliance

EMC Regulations: EN 61000-6-2 / EN55011:1998+A1
Performance Tests: ISO 10770-1
Pressure Rating: EN 10771
Hydraulic Interface: ISO 10372-01-01-0-92

Not to scale.

Ordering Code

S4 Pro 1 2 3 4 5 6 7 8 9

Any value in range 0.5 to 18

Rate flow in l/min for 35 bar ∆P per control edge

R – Suffix for reversal of A and B port e.g. 18R

A	Axis cut (1% overlap linearized)
O	3% Overlap (linearized to 50% gain over center)
D	10% Overlap (with flow dead band)
X	For other options please enquire

A	± 10 V
B	± 20 mA
C	4 to 20 mA
D	± 5 V
X	For other options please enquire
	For differing input and output signals, use two letters, e.g. AC denotes ± 10V input and 4 to 20 mA output

C	Center
X	For other options please enquire

E	6 pin + PE circular connector*
E4	4 pin circular connector*
B4	4 contact, unterminated flying lead
G	G4-20P Rack and Panel connector
X	For other options please enquire

* EN 175201-804/MIL 5015 equivalent connector, shell size 14

Y	Enable mode on (Only available with connector option E)
N	No enable functionality

R	Recommended – any hydraulic oil in accordance with DIN 51524, filtered in accordance with ISO4406 18/16/13. Compatibility with water-free synthetic fluids available on enquiry.
X	For other options please enquire

N	Nitrile
V	Viton
X	For other options please enquire

Assigned individually to any with customized options upon enquiry

Variants on Request

Domin is proud of their ability to offer tailored solutions that meet customers’ specific needs. If you require a non-standard configuration, or a bespoke modification, we are confident we can provide you with the best solution. Talk to us here and one of our team will respond as soon as possible.

Domin is a supplier and servo valve manufacturer for various applications including automotive/motorsports, aerospace, animatronics, simulation, robotics, and marine.