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I/H Converter DSG

I/H Converter, Current to Pressure Converter (CPC),
Electro-hydraulic Converter, Electro-hydraulic Actuator Control for Steam Turbines and Other Applications

Voith electro-hydraulic I/H converters are current-to-pressure converters (CPC), which adjust hydraulic positioning cylinders by means of a pilot valve. The positioning cylinders operate a valve that controls the mass flow needed to drive machinery. Voith I/H converters (CPC) ensure very precise and high dynamic control of the mass flow.

I/H converters change a constant input pressure into a variable output pressure. A standard 0/4 – 20 mA signal specifies the output pressure. The major components of the I/H converter are a hydraulic unit and a force-controlled electromagnet.

The I/H converter features a simple and compact design. This ensures reliable operation. The Mean Time Between Failures (MTBF) for Voith I/H converters is over 600 years. Your equipment runs for a very long period of time without unplanned downtime; availability is increased.

The I/H converter (CPC) is also available in a redundant design (hot redundancy): DSM I/H Converter Module (DX-CPC)


Voith Digital Solutions GmbH
Actuators and Governors
Voithstr. 1
74564 Crailsheim, Germany

Tel. +49 7951 32-470
Fax +49 7951 32-605

Product inquiry


Flow rate Up to 140 l/min [37 gpm] at 1 bar [14.5 psi] differential pressure
Input pressure Up to 70 bar [1,015 psi]
Maximum output pressure range 0 – 35 bar [0 – 508 psi]
MTBF (Mean Time Between Failures) 600 years (calculated in accordance to MIL‑HDBK‑217 and Siemens SN 29500, actual MTBF evaluations from installed products show even higher values)
Supply voltage 24 VDC
Current consumption 1.0 A (3.0 A for t < 1 s)
Input signal 0/4 – 20 mA
Fail-safe operation Fail-safe position through output pressure
Explosion proof rating (optional)
  • ATEX (II 2G IIC T4, Ta = -30...+60°C)
  • CSA C/US (Class 1, Div. 1, 2, Group B, C, D, Temp. Code T4)
  • IECEx (Ex db llC T4, Ta = -30...+60°C)
  • KOSHA (Ex db llC T4, Ta = -30...+60°C)
  • others on request
Protection class IP 65
Safety integrity level SIL 2

Advantages and benefits

  • The Mean Time Between Failures (MTBF) is over 600 years. Your equipment operates very reliably. Productivity increases and the costs associated with lost production remain low.
  • Voith I/H converters are insensitive to contaminated pilot oil. Turbine lubricating oil is suitable as the operating fluid. One oil supply system for both lubricating and pilot oil suffices. Maintenance is simple, which helps you lower operating costs.
  • Very good control response, almost no hysteresis and a resolution better than 0.1% ensure very fast and accurate control. You benefit from having a stable process with high product quality.
  • Connections are industry-standard. This means the I/H converter can be integrated into your equipment easily. Standard adapter plates are available to allow the I/H converter to interface with systems designed for Woodward CPC and CPC‑II converters. You reduce the costs for system integration.
  • The output pressure range can be adjusted easily on-site by means of pot­enti­ometers. This allows you to adjust the output pressure for the application quickly and without any delays.
  • For use in hazardous areas, we offer explosion proof I/H converters with the required certificates.

Typical fields of use

  • Operation of the control valve of
    • steam turbines
    • gas turbines
    • compressors
  • Retrofit of mechanic-hydraulic valve controls
  • Upgrade of systems with Woodward CPC or CPC-II converters

Technical information


A Load connection (output)
T Tank connection
P Oil supply connection (input)
Control magnet housing
2 Plunger
3 Potentiometers
4 Manual adjustment
5 Electrical connection
6 Hydraulic section
7 Control piston



With the aid of a controller, a force FMag is generated in a 24-V DC magnet. This magnetic force is proportional to the 0/4 – 20 mA input signal. The desired output pressure range is set by means of two potentiometers X0 and X1.

The combination of electronic control, measurement of the magnetic flux, the physical design of the magnet and hydraulic pilot control results in an almost hysteresis-free, dynamic functional unit.

The control magnet applies the force FMag to the control piston. This force acts in opposition to the hydraulic force FHydr, which results from the pressure at the A port applied to the face of the control piston (pressure balance). As a consequence of this control, the exactly required pressure and oil flow needed to position the steam or fuel valve are always available in the output line A of the I/H converter.

A Load connection (output)
T Tank connection
P Oil supply connection (input)
X0, X1 Parameters for output pressure range (potentiometers)
w Output pressure setpoint
F Force
FMag Magnetic force
FHydr Hydraulic force
U Voltage
UHall Hall voltage


Selection table

Typ Maximum
pressure [bar]
Control range
of the output
pressure [bar]
Flow rate [l/min] at
1 bar differential pressure
P > A A > T
DSG -B03XXX 40 0 – 3 30 30
DSG -B05XXX 40 0 – 5 30 30
DSG -B05X48 20 0 – 5 100 140
DSG -B07XXX 40 1 – 7 30 30
DSG -B10XXX 40 0 – 10 30 30
DSG -B30XXX 70 0 – 30 30 30
DSG -B35XXX 70 10 – 35 30 30