PID / Pressure controls

PID and pressure control modules for general use with pressure valves or variable displacement pumps and p/Q control modules for flow control and closed loop pressure limitation control

 

General Information

Application Note Pressure control with automatic commissioning assistant

AN-104-EN

 


MDR-339-P-IO

Digital pressure controller with integrated power amplifier, commissioning assistant and IO-Link interface

Typical applications:

  • Pressure control with pressure valves and servo pumps and
  • Speed control with analogue speed sensors (tacho)
  • Digital setpoint specification, parameterisation and monitoring via IO – Link

Advantages:

  • Optionally one or two control loops can be operated
  • Assistance system as commissioning support
  • Integrated power output stages, thus optimum overall solution
  • Sensor signals and diagnostic data are available via IO-Link, analogue inputs of the PLC can be eliminated
  • Parameterisation optionally via IO link or WPC (USB interface)
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This module controls the pressure (and optionally the speed) in one or two hydraulic systems. Two power output stages for proportional valves are integrated. It can also be used for a variety of other applications where the combination of PID controller, feedforward control and unidirectional output stage is required.

The unit also offers a commissioning wizard for determining optimum pilot control characteristics and for dynamic controller adjustment. In this way, it is possible to compensate for non-linearities of the systems. Due to the adjusted feedforward control, the control algorithm only has to compensate for small deviations, which means that the system reacts quickly and with minimal overshoot.  The automatic setting of the controller parameters enables particularly fast and uncomplicated handling.

The setpoints are specified via IO-Link, and the actual values as well as status and diagnostic information can be called up via this connection. The unit has a port compatible with class A. Galvanic isolation between the IO-Link interface and the supply voltage ensures optimum immunity to interference.

The controlled variables are read in via 0…10 V signals (or 4…20 mA with cable break monitoring). The output current is regulated and therefore independent of the supply voltage and the solenoid resistance. The output stage is monitored for cable break and overcurrent (short circuit) and switches off in the event of a fault. Operation is simple and application-oriented, which ensures a very short training period.

MDR-339-P-IO


 

MDR-337-P

Pressure control with integrated power amplifier and automatic commissioning assistant

Typical applications:

  • pressure control with pressure valves, also for variable displacement pumps

Due to the linearization, particularly good dynamics and precision can be achieved.

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This module controls the pressure (and optionally the speed) of a hydraulic system. Integrated is a power amplifier for proportional valves.

This device corresponds to the technical data of the MDR-137-P, however, the module additionally has a commissioning assistant for the determination of an optimal pilot control characteristic and dynamic controller adjustment.

In this way, it is possible to optimally compensate for nonlinearities of the system. Due to the adapted pre-control, the control algorithm only has to compensate for minor deviations, which means that the system responds quickly and with the slightest overshoot.

The patented MR controller can also be activated for closed loop control, combining robust behavior with excellent dynamic characteristics.

The automatic setting of the controller parameters allows particularly fast and uncomplicated handling.

MDR-337-P


PID-131-U

Standard PID controller

Typical applications:

dynamic PID compensator for

  • force
  • pressure and
  • speed control
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This module was developed for general controlling of dynamic systems. The controller structure is designed as a classic PID compensator with a short cycle time of 1ms. It is possible to choose out of different sensor and command signal types and polarities as 20… 4 mA, 4… 20 mA, 0… 10 V or 10… 0 V. More special input signals can be freely adapted via a mathematical scaling function.

The output signal is available as an active differential signal for the direct connection of valves with integrated electronics. A current signal is parameterizable here, too.

For the controller, the user may choose between two parameter sets.

REMOTE CONTROL for commissioning is possible.

PID-131-U


PQ-132-U

p/Q controller, pressure limitation controller for hydraulic axes

Typical applications:

  • electronic 3-way pressure control
  • pressure limitation control and
  • differential pressure control
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This module was developed for controlling pressure and force of hydraulic drives, worked out as a classical p/Q controller (flow control with closed loop pressure limitation function).

The command values are set via analog signals or as fixed parameters and the module is controlled with digital inputs.

The output signal is available as an active differential output for direct connecting of control valves with integrated electronics. Alternatively, a current output can be parameterized.

The control loop works with a cycle time of 0,5… 3 ms (adjustable). The controller is equipped with two sets of parameters, which can be switched in case of critical applications with different operating points. Programmable are the standard PID control parameters and an additional activation threshold for the integrator. The system is monitored internally for various errors. These are indicated by the digital output signal and the corresponding LED.

PQ-132-U


MDR-133

Pressure control module

Typical applications:

  • pressure control with pressure relief valves and/or
  • pressure reducing valves
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This module was developed for control of pressure and force in hydraulic systems. The control structure is optimized for pressure closed-loop control systems with typical pressure valves.

The controller works in a bypass control function, where the input signal is linked directly to the control output (pressure valve) and the PID compensator has to control the linearity deviations only. In many cases, the optimization can be carried out without further test equipment (only a pressure sensor is needed).

The output signal is available as 0… 10 V or 4… 20 mA signal for the direct connection of valves with integrated electronics. External amplifiers and our power plug can be used, too.

Alternatively, the controller is available with an integrated power output stage. The advantage of the integrated power output stage is founded in the integrated control behavior without additional dead times. This allows higher dynamics and higher stability respectively.

MDR-133-U/P


MDR-137-P

Pressure control module with integrated power amplifier

Typical applications:

  • pressure control with pressure valves and servo pumps as well as
  • speed control with analog speed controllers (speedometer).
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This module has been developed for controlling pressure and force (and optionally the speed) in hydraulic systems. A power stage for proportional valves is integrated. Various parameter settings allow an optimal adaptation to the respective valve. The control circuit operates with a control cycle time of 1 ms and the integrated power stage with a cycle time of 0,125 ms for the solenoid current control.

The demand and the actual value are read in via a 0 … 10 V signal (optionally 4 … 20 mA with cable break monitoring). The ramp function and the PID controller are universally applicable. The output current is closed loop controlled and thus independent of the supply voltage and the solenoid resistance. The power output stage is monitored for cable break and overcurrent (short circuit) and switches off in the event of a fault.

Programmable are the standard PID control parameters and a threshold value for the integrator limitation and activation as well as various parameters for valve adaptation.

MDR-137-P


SCU-138-P

Speed control unit with integrated power stage

Typical applications:

  • speed control with pulse generators
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This module was developed for controlling a universal closed loop control system for speed and velocity control. A power stage for proportional valves is integrated. Various parameter settings allow an optimal adaptation to the corresponding valve. The controller runs with a loop time of 1 ms and the power stage with 0,125 ms for the current control.

The command value is set via an analog input signal in the range of 0… 10 V or 4 … 20 mA. Optionally, a PWM input signal can be used. Alternatively, a command value can be programmed internally (fixed speed control for generators). The ramp function and the PID controller are universally usable. The output current is closed loop controlled and therefore independent of the supply voltage and the solenoid resistance. The power output stage and current input signals are monitored for cable break and switch off in case of detected errors.

Programmable are the standard PID control parameters and a threshold value for integrator limitation and activation as well as various parameters for the valve adaptation.

SCU-138-P