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I/H Converter Module DSM

I/H Converter Module, Redundant I/H Converter, Redundant Current to Pressure Converter Assembly, Dual/Duplex Current to Pressure Converter (DX-CPC)

Voith I/H converter modules are redundant dual/duplex current-to-pressure converters (DX-CPC), which adjust hydraulic positioning cylinders by means of a pilot valve in processes requiring high availability. The positioning cylinders operate a valve that controls the mass flow needed to drive machinery. The pressure control module provides very precise and high dynamic control of the mass flow.

An I/H converter module consists of two I/H converters connected in parallel. An I/H converter changes a constant input pressure into a variable output pressure. A stand­ard 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.

Every I/H converter has a monitoring circuit that detects a malfunction of the con­verter. In the event of converter malfunction, a hydraulic maximum selection circuitry ensures that the other I/H converter assumes control automatically. This makes it possible to remedy the cause of the malfunction during operation.

The Mean Time Between Failures (MTBF) for Voith pressure control modules is over 20,000 years. Your equipment runs for a very long period of time without unplanned downtime; availability is increased.


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

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

Product inquiry

Technical data

Flow rate Up to 30 l/min [7.9 gpm] at 1 bar [14.5 psi] differential pressure
Input pressure Up to 40 bar [580 psi]
Maximum output pressure range 0 – 10 bar [0 – 145 psi]
MTBF (Mean Time Between Failures) 20,000 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 4 – 20 mA
Fail-safe operation Fail-safe position through output pressure
Redundancy Hot redundancy
Ambient temperature -20 to +80°C [-4 to 176°F] (standard version, not rated for
use in potentially explosive areas)
Explosion proof rating (optional)
  • ATEX (II 2G IIC T4, Ta = -20...+60°C)
  • CSA C/US (Class 1, Div. 1, 2, Group B, C, D, Temp. Code T4)
  • others on request
Protection class IP 65
Safety integrity level SIL 2

Advantages and benefits

  • Thanks to the redundancy provided by the two I/H converters, the Mean Time Between Failures (MTBF) for the pressure control module is over 20,000 years. Your equipment operates with maximum availability. Productivity increases and the costs associated with lost production remain low.
  • It is possible to replace a faulty I/H converter during operation. You avoid un­planned downtime and their associated high costs.
  • Voith pressure control modules are not sensitive 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 module can be integrated into your equipment easily. Standard adapter plates are available to allow the I/H converter module 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 potenti­ometer. 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 pressure control modules 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 Voith DSG I/H converters
  • Upgrade of systems with partially or non-redundant Woodward CPC or CPC‑II converters

Technical information


Process control system; control magnet | hydraulic pilot control, hydraulic maximum selection circuitry

The pressure control module employs a two-channel design. A redundant control system provides the two input signals w1 and w2 for the two I/H converters. The hydraulic output pressure pA1 or pA2 from each of the I/H converters is proportional to the applied 4 – 20 mA input signal. The two pressures are connected to a hydraulic maximum selection circuitry, which then selects the higher pressure.

Lowering the setpoint from the control system gradually during operation allows additional built-in pressure sensors to provide continuous monitoring of the hy­draulic function. This pressure variation makes it possible to diagnose each of the subsystems while operating. Each I/H converter has an electronic monitoring circuit that detects a malfunction of the converter. If one I/H converter fails, a hydraulic maximum selection circuitry ensures that the other converter assumes control automatically. The output pressure from the correctly operating I/H converter is used. This makes it possible to remedy the cause of the malfunction during operation.

A Load connection (output)
T Tank connection
P Oil supply connection (input)
X0, X1 Parameters for output pressure range (potentiometers)
F Force
FMag Magnetic force
FHydr Hydraulic force
U Voltage
UHall Hall voltage
w1, w2 Output pressure setpoints
pA1, pA2 Hydraulic output pressure


Selection table

Typ Maximum
pressure [bar]
range [bar]
Flow rate [l/min] at
1 bar differential pressure
P > A A > T
DSM -B05XXX 40 0 – 5 30 30
DSM -B10XXX 40 0 – 10 30 30