Implementing a servo-hydraulic system with the ABB SPHSS13 module requires careful planning and precise execution. This guide provides a practical, step-by-step overview for control engineers and technicians, covering the key considerations for selection, installation, wiring, and commissioning of this critical motion control component.
Warning: Working with hydraulic systems and high-voltage electronics requires qualified personnel. Lock out/tag out all energy sources (electrical and hydraulic) before beginning work.
The SPHSS13 must be matched correctly with the other components in the servo loop.
Servo Valve Compatibility: This is the most critical check. Confirm that the SPHSS13's output current range and electrical characteristics are compatible with your specific servo valve model. The valve's datasheet will specify the required drive current and coil impedance.
Controller Compatibility: Ensure your main controller (e.g., ABB Advant OCS, MOD) can provide a compatible analog command signal (typically ±10 V) and receive the necessary feedback.
Feedback Sensor: Verify the module supports the type of feedback sensor used (e.g., LVDT).
The SPHSS13 is designed for DIN rail mounting. Securely mount it in the control cabinet in a location with adequate airflow.
Connect the module to a stable, well-regulated power supply as specified in the manual. This is typically a 24V DC or a higher voltage AC/DC supply. Ensure correct polarity for DC supplies.
Command Input: Connect the analog command signal (±10 V) from the motion controller to the designated input terminals on the SPHSS13. Use shielded, twisted-pair cable and ground the shield at one end to prevent noise interference.
Feedback Input: Connect the signal from the position transducer (LVDT) to the module's feedback input terminals. Again, use shielded cable.
Connect the high-current output terminals of the SPHSS13 directly to the torque motor coils of the servo valve.
Use the cable type recommended by the servo valve manufacturer, which is often a specialized, robust cable designed to handle the current and resist noise.
Pay close attention to the polarity as indicated in the manuals; reversing the connections can cause the valve to operate in the wrong direction.
Connect the external enable signal if your safety system requires it. This allows a safety circuit to disable the module.
Wire the module's fault relay output to your controller or alarm system to be notified of any faults (e.g., coil break, overcurrent).
Configuration is often done via potentiometers (pots) or DIP switches on the module itself, rather than software.
Gain/Amplification Adjustment: Adjust the gain pot to set the relationship between the input command voltage and the output current. This should be set according to the servo valve's specifications and the desired system response.
Null/Offset Adjustment: This pot is used to fine-tune the output current when the command signal is zero, ensuring the servo valve is truly in its neutral position. This is critical to prevent "creep" in the actuator.
Other Settings: Refer to the manual for other adjustable parameters, such as feedback conditioning or fault detection thresholds.
Commissioning a servo-hydraulic system must be done methodically and safely.
Initial Checks: Double-check all wiring. Ensure hydraulic pressure is off.
Power Up Electronics: Apply power to the control system and the SPHSS13. Verify that the "Power" LED is on and no fault indicators are active.
Test without Hydraulic Pressure:
With the hydraulic system still depressurized, enable the module.
Use the controller to send a very small command signal (e.g., 0.1 V).
Observe the servo valve. You may hear a slight hum as the torque motor is energized. The valve spool should not shift significantly without pressure.
Check that the feedback signal is being read correctly.
Apply Hydraulic Pressure and Test:
Slowly apply hydraulic pressure.
Start with very small commands and observe the actuator's movement. Does it move in the correct direction? Does it respond smoothly?
Direction Correction: If the actuator moves the wrong way, swap the connections to the servo valve torque motor.
Loop Tuning: Once basic operation is confirmed, the control loops (position, velocity) need to be tuned in the main motion controller for optimal performance (response speed and stability).
No Movement, No Fault:
Check the enable circuit is active.
Verify the command signal is present at the module's terminals.
Check the servo valve connections.
Erratic or Unstable Motion:
Often caused by incorrect gain settings (too high) or noise.
Reduce the gain on the SPHSS13 or in the controller.
Re-check shield grounding on all signal cables.
Fault Indicator Active:
Consult the manual for the fault code (often indicated by LED blinking patterns).
Common causes: open circuit (broken wire) or short circuit in the servo valve coil.
Integrating the ABB SPHSS13 requires a meticulous approach to wiring, configuration, and commissioning. By carefully matching components, following noise-reduction best practices, and adopting a step-by-step testing procedure, you can successfully deploy this powerful module to create a high-performance, reliable servo-hydraulic motion control system.
