Rexroth Bosch Group VT2000 Proportional Amplifier

If the width of the front panel is different (4X is different width), blind plates need to be ordered.

Check if the power supply is still 24VDC (the old system may have used other voltages).

The original 4X may not have over temperature protection, while the 5X does, but it will not affect its functionality.

8.2 Installation precautions

The amplifier must be plugged in and out in a power-off state.

Do not use a plug with a freewheeling diode to connect the electromagnet, as it may damage the PWM waveform and potentially damage the output stage.

When measuring, only high internal resistance instruments (≥ 100k Ω) can be used, and ordinary pointer multimeters may cause measurement errors.

Measurement zero position MO cannot be connected to a 0V power supply! This means that the oscilloscope ground clip cannot be randomly connected to the MO, and differential probes or isolation channels should be used instead.

8.3 Electromagnetic Compatibility (EMC) and Wiring

Command value cable shielding layer single ended grounding (amplifier side).

The amplifier itself is grounded through terminal 6 or 8. If there is no system ground, ground the 0V power supply.

Electromagnetic cables should also be shielded and laid separately from power cables.

Maintain a distance of at least 1 meter from radio, radar, and other equipment.

8.4 Safety related

The electrical signals (such as actual values) derived from control electronic devices shall not be used to switch safety related machine functions. Pressure safety still relies on independent mechanical safety valves or designs that comply with prEN 982 standards.

Common Failure Modes and Solutions

9.1 The valve does not move at all, and the measurement of the "I" socket is 0

Check for 24V power supply; Is the fuse blown.

Check if the instruction value is actually sent (use a multimeter to measure 12ac or 28c for MO).

Check if the Gw potentiometer has been mistakenly adjusted to the minimum.

Check if the amplifier is overheated (cool down and try again).

9.2 The valve can operate but the pressure is low, and even the maximum command value cannot reach the system pressure

Measure whether the "w" socket reaches 6V at the maximum command value. If not, adjust the Gw potentiometer clockwise to increase.

Measure whether the "I" socket reaches 800mV. If it is below 800mV but "w" is already 6V, it may be due to output stage current limiting or high electromagnetic resistance (>30 Ω). Check the coils and cables.

Check if the bias current is set too high (Zw R130), causing the available adjustment range to be compressed.

9.3 Slow pressure response and long slope time

Check if the S1 jumper is in the "5s" position and if the ramp potentiometer is set too large. Try to reduce the slope time.

If the external rapid ramp contact remains closed, it will force a minimum ramp time (about 30ms) and the response will be fast. On the contrary, if the contact is disconnected, follow the set ramp time.

9.4 Pressure fluctuations or oscillations

Check if the clock frequency setting (100Hz or 200Hz) matches the valve. Some valves are sensitive to vibration frequency.

Check whether the shielding and grounding are good, and whether there is electromagnetic interference.

Check if the electromagnetic cable is too long (recommended cable not used for>50m).

9.5 After replacement, the amplifier cannot be inserted into the original card slot

Confirm if the card slot is VT3002-2X/32 type (standard Euro card slot). If it is a dedicated card slot, an adapter may be required.

How to obtain spare parts and technical support

Due to the fact that VT2000 belongs to an older series, Bosch Rexroth may have classified it as an outdated product. Users can obtain support through the following channels:

Contact Rexroth's official spare parts department to inquire if there are any remaining inventory or refurbished parts.

Use an independent repair service provider (such as Artisan Technology Group in the document source) to provide used or repaired equipment.

Consider upgrading to a newer amplifier series (such as VT-VSPA2 or VT-VRPA), but require reconfiguration of wiring and parameters.

When ordering second-hand or refurbished parts, be sure to confirm:

Complete model (VT2000 5X)

Whether the jumper settings comply with the application (the supplier may be required to pre configure according to the settings provided by the user)

Is there a test report attached (especially for output current accuracy and ramp time)