The P-843 preloaded piezo actuators are laboratory devices designed for indoor use in an environment that is free of dirt, oil, and lubricants. They are intended for use in areas where failure would result in considerable risks for human beings or the environment. The P-843 must be operated with suitable electronics from PI. The electronics are not in the scope of delivery of the P-843. The P-843 may not be used for purposes other than those stated in this user manual. The P-843 may only be used in compliance with the technical specifications and instructions in this user manual.
Function Description
The P-843 preloaded piezo actuators convert electrical energy into mechanical displacement, providing precise and dynamic positioning capabilities. They are designed to operate with external piezo amplifiers/servo controllers, which supply the necessary voltage to drive the actuator. The actuators are preloaded, meaning they are designed to maintain a constant preload force, which is crucial for their performance and longevity, especially in dynamic applications. The P-843 series offers various travel ranges and force capabilities, making them suitable for a wide array of applications requiring high-resolution motion. The devices are equipped with a sensor for position feedback, enabling closed-loop control and enhanced accuracy.
Important Technical Specifications
The P-843 series includes several models, each with specific travel ranges and associated gauge sensors.
- P-843.10: Preloaded piezo actuator, 15 µm travel range, 800 N / 300 N, strain gauge sensor.
- P-843.20: Preloaded piezo actuator, 30 µm travel range, 800 N / 300 N, strain gauge sensor.
- P-843.30: Preloaded piezo actuator, 45 µm travel range, 800 N / 300 N, strain gauge sensor.
- P-843.40: Preloaded piezo actuator, 60 µm travel range, 800 N / 300 N, strain gauge sensor.
- P-843.60: Preloaded piezo actuator, 90 µm travel range, 800 N / 300 N, strain gauge sensor.
General Specifications (across all models unless specified):
- Travel Range: 15 to 90 µm (depending on model).
- Push Force Capacity: 800 N.
- Pull Force Capacity: 300 N.
- Torque on Tip: 0.35 Nm max.
- Electrical Capacitance: 1.5 to 9 µF (depending on model).
- Resonant Frequency (no load): 18 to 6 Hz (depending on model).
- Operating Temperature Range: -40 to 80 °C.
- Mass without cable: 31 to 127 g (depending on model).
- Length L: 37 to 127 mm (depending on model).
- Voltage Connector: LEMO FFA.00.250 (coaxial).
- Sensor Connector: LEMO FFA.0S.304.
- Cable Length: 1 m.
- Sensor: Strain gauge sensor (SGS).
- Resolution: 0.3 to 1.8 nm (depending on model).
- Small Signal Stiffness: 57 to 10 N/µm (depending on model).
- Maximum Altitude: 2000 m above msl.
- Air Pressure: 1100 hPa to 100 hPa.
- Relative Humidity: Highest relative humidity 80 % for temperatures up to 31 °C, decreasing linearly to 50 % relative humidity at 40 °C.
- Storage Temperature: -20 °C to 80 °C.
- Transport Temperature: -20 °C to 80 °C.
- Overvoltage Category: II.
- Protection Class: I.
- Degree of Pollution: 1.
- Degree of Protection: IP20 according to IEC 60529.
The P-843 actuators are designed to be used with specific piezo amplifier modules (E-503, E-505, E-610, E-617, E-621, E-625, E-663, E-665, E-709, E-831). These modules provide the necessary voltage range (-30 to 130 V or -20 to 120 V for E-663) and control for the actuators.
Usage Features
Installation and Mounting:
- Avoiding Mounting Errors: Piezo actuators are sensitive to angular errors, axial loading, and torsion. It is crucial to avoid these errors during mounting to prevent damage and ensure optimal performance. Figures illustrate correct and incorrect mounting scenarios, emphasizing the importance of proper alignment and avoiding overtightening.
- Protective Earth Conductor: The P-843 must be connected to a protective earth conductor. This is a critical safety measure to prevent electric shock. The mounting hole in the base of the P-843, suitable screws, and conductive screw are essential for this connection.
- Fixing the Load: The open-end wrench should be used to hold the tip of the P-843 in place while tightening the nut to secure the load. This prevents twisting of the actuator.
- Connecting the P-843: The P-843's voltage plug connects to the voltage socket on the electronics, and the sensor plug connects to the sensor socket on the electronics.
Determining Operating Parameters:
- Resonant Frequency: The operating frequency should not exceed one third of the resonant frequency of the loaded piezo actuator. This is crucial for preventing dynamic overload.
- Maximum Push/Pull Force Capacity: The mass of the load to be moved and the operating frequency of the piezo actuator must be selected so that the dynamic forces generated during operation do not exceed the maximum push/pull force capacity of the piezo actuator.
- Maximum Permissible Operating Temperature: The operating voltage, operating frequency, and the temperature generated in the piezo actuator must be considered. The maximum permissible operating temperature of the piezo actuator is not exceeded if the operating frequency, operating voltage, and operating time meet specified limits.
- Maximum Power Consumption: The power consumption of the unloaded, uncooled piezo actuator operating at a voltage of 100 V peak-to-peak with the operating frequency from column B of the maximum ratings table.
Discharging the P-843:
- Connected to Electronics: To discharge, set the piezo voltage to 0 V on the electronics.
- Not Connected to Electronics: Insert the P-843's voltage connector into the switched-off electronics from PI and maintain the connection for a few seconds.
Maintenance Features
Cleaning:
- Requirements: The P-843 should be disconnected from the electronics before cleaning.
- Auxiliary Materials Required: Soft, lint-free cloth and a mild cleaning agent or disinfectant.
- Procedure: Dampen the cloth with the cleaning agent or disinfectant and carefully wipe the surfaces of the P-843.
- Important Notes:
- Avoid short-circuiting due to cleaning fluid penetrating the housing. Cleaning fluid penetrating the P-843's housing can short-circuit the actuator and drive electronics.
- Disconnect the P-843 from the electronics before cleaning.
- Prevent cleaning fluid from penetrating the P-843's housing.
- Damage due to unsuitable cleaning agents: Some cleaning agents may cause damage to the P-843. Use mild cleaning agents or disinfectants only.
- Damage from ultrasonic cleaning: Ultrasonic cleaning can damage the P-843. Do not do any ultrasonic cleaning.
Troubleshooting:
The manual provides a comprehensive troubleshooting guide for various issues:
- No or Limited Motion:
- Check cable connections.
- Do not exceed the maximum push/pull capacity according to specifications.
- Readjust the sensor's zero-point (see manual for the electronics).
- If possible, replace the defective actuator with another actuator and test the new combination.
- Reduced Accuracy:
- Recalibrate the axis displacement (see controller manual) or contact customer service.
- In the case of calibrated systems, pay attention to the assignment of the axes when connecting several piezo actuators to a multi-channel controller.
- The Piezo Actuator Starts Oscillating or Positions Inaccurately:
- Switch off the servo mode of the corresponding axes immediately.
- Check the servo control parameter settings on the controller.
- Adjust the servo control parameters on the controller according to the load change.
- Operating with an Excessively High Frequency:
- Operate the piezo actuator at a maximum of one third of the resonant frequency.
- Reduced Lifetime of the Piezo Actuator Due to Permanently High Voltage:
- The permanent application of a high voltage to piezo actuators leads to a considerable reduction in the lifetime of the piezo ceramic.
- When the P-843 is not being used (e.g., to ensure temperature stability of the electronics), discharge it.
- If possible, limit the maximum operating voltage during continuous operation.
- Operating Voltage Excessively High or Incorrectly Connected:
- Operating voltages that are too high or incorrectly connected can cause damage to the P-843.
- Pay attention to the operating voltage range and pin assignment.
- Damage After Reconnecting Due to a Charged P-843:
- The P-843 can remain charged when the connecting cable is pulled out of the electronics during operation. Reconnecting a charged P-843 to electronics during operation can cause a mechanical impulse that will damage the P-843.
- Do not pull the connecting cable of the P-843 out of the electronics during operation.
- If the connecting cable of the P-843 is accidentally pulled out of the electronics during operation, switch off the electronics before you reconnect the P-843.
- Destruction of the Piezo Actuator Due to Overheating:
- Overheating can destroy the piezo actuator.
- Adjust the operating voltage, operating frequency and/or operating time so that the maximum operating temperature of the piezo actuator is not exceeded.
- Uncontrolled Oscillation:
- Oscillation can cause irreparable damage to the P-843. Oscillation is indicated by a humming noise and can be caused by the following:
- A change in the load and/or dynamics requires the servo-control parameters to be adjusted.
- The P-843 is operated near to its resonant frequency.
- If you notice oscillation:
- In closed-loop operation, switch off the servo mode immediately.
- In open-loop operation, stop the P-843 immediately.
Transportation and Disposal:
- Transportation: Pay attention to ambient conditions and classifications. Pack the P-843 in the original packaging. If the P-843 is to be sent, use a stable outer box.
- Old Equipment Disposal: Dispose of your old equipment according to international, national, and local rules and regulations. PI undertakes environmentally correct disposal of all PI equipment free of charge, if it was made available to the market after August 13, 2005.
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