Hydraulic Servo Valves – S12 Pro

Compact Power. Proven Reliability.

The S12 Pro is a highly dynamic hydraulic servo valve designed for NG16 (CETOP 7) ports. Its performance includes a flow range of 66-153 gpm (250-580 lpm), frequency over 100 Hz, and a response time of <6.5 ms. This model offers the largest flow capability of 153 gpm, and is suited for applications in press and forming, power and energy, and industrial testing. 

Built on a two-stage architecture using Domin’s proven valve technology as a pilot stage, it prioritizes stability, durability, and consistent performance under heavy load.

The S12 Pro delivers stable, responsive control across the operating range, maintaining integrity even in the most demanding conditions, ideal for systems where instability cannot be tolerated.

With dimensions of 13.25 in (377 mm) in length and 6.9 in (177 mm) in height, the S12 Pro is thoughtfully designed with all components fully enclosed, eliminating exposed wires or sensors. This user-focused design element ensures not only a clean, sleek appearance, but also easier handling and installation.

This combination of performance and compact design makes the S12 Pro ideal for applications in industrial manufacturing, test simulation, and the energy sector.

If you are looking for faster response times with lower flow capabilities, view our most popular model, the S6 Pro, which offers response times less than 3.5ms and a flow range of 1.6 to 15.9 gpm (6 to 60 lpm). If you don’t require the dynamic high performance of an S Series servo valve, view our cost-effective P12 Pro.

Popular Upgrade Models:

Key Stats:

Key Features:

Standard Modification Options:

The S12 Pro is designed to be customized. Standard modifications include:

Technical Data:

General Data

Design		Two-Staged Servo Valve
Actuation		Direct Drive Pilot
Size		NG16
Mounting Interface		ISO 4401-07-07
Ambient Temperature	ºC (ºF)	-20 to +60 (-4 to +140)
Mass	kg (lb)	< 7 (15.4)
Vibration Resistance	g	10
Shock Resistance	g	15
IP		IP65

Hydraulic Data

Max. Operating Pressure (P, A, B, X)	Bar (psi)	350 (5,000)
Max. Operating Pressure (Y, T)	Bar (psi)	250 (3,600)
Fluid		Hydraulic Oil DIN 51524-535
Fluid Temperature	ºC (ºF)	-20 to +60 (-4 to +140)
Viscosity	cSt	10 to 400
Rated Flow (35 Bar △P per edge)	l/min (US gal / min)	580 (153)
Flow Maximum	l/min (US gal / min)	1000 (264)
Pilot Leakage	l/min (US gal / min)	0.8 (0.21)
Main Stage Leakage	l/min (US gal / min)	1.0 (0.26)
Filtration		ISO 4406 (1999) 18/16/13

Static/Dynamic Data

Response Time at 100% Step Input	ms	< 6.5
Frequency Response (-3dB gain, ±25% signal)	Hz	> 130
Frequency Response (-90deg phase, ±25% signal)	Hz	> 100
Hysteresis	%	< 0.2
Threshold	%	< 0.1
Null Shift	%	< 1

Performance Graphs

View performance graphs for the S12 Pro Domin Servo Valve below including Step Response and Frequency Response:

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Electronic Interface Diagrams

6 + PE Circular Connector (Code E)

Type: Case Mounted
Termination: Connector according to EN 175201-804/MIL 5015 equivalent, shell size 14
Number of Contacts: 7

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.

4 Pin Circular Connector (E4)

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 signal, +
C	Input –	Differential input signal, –
D	Supply 0 V	0 V

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

Unit Dimensions + Mounting Dimensions

Unit Dimensions

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

Mounting Surface Pattern

	Dia Ø mm	X Position mm	Y Position mm
P	20	50	14.3
A	20	34.1	55.6
B	20	65.9	55.6
T	20	18.3	14.3
L	6.3	0	34.9
X	6.3	76.6	15.9
Y	6.3	88.1	57.2
F1	M10	0	0
F2	M10	101.6	0
F3	M10	101.6	69.9
F4	M10	0	69.9
F5	M6	34.1	-1.6
F6	M6	50	71.5

* Valves includes seal grooves for X and Y ports for installation in existing systems X and Y connections are NOT required for valve operation.

Bolts (F1, F2, F3, F4)

Type: M10 x 50 mm DIN EN ISO 4762-8.8
Req.Torque: 40 Nm (29.5 ft-lbf)

Bolts (F5, F6)

Type: M6 x 50 mm DIN EN ISO 4762-8.8
Req.Torque: 8 Nm (5.9 ft-lbf)

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

Type: 22.22 x Ø 2.62
Material: NBR or Viton, 90 Shore A

O-Rings (L, X, Y)

Type: 10.82 x Ø 1.78
Material: NBR or Viton, 90 Shore A

Standards Reference

EMC Regulations: Immunity: EN 61000-6-2, Emission: EN61000-6-3
Performance Tests: ISO 10770-1
Pressure Rating: ISO 10771
Hydraulics Interface: ISO 4401-07-07*

* Ports over-sized to Ø 20 mm.

Domin is a supplier and servo valve manufacturer for various applications including large industrial processes, test & simulation rigs, turbine & power generation systems, high power motion platforms, and industrial test systems.