Functional description using the A4VS axial piston pump with HS5 control as an example
The swivel angle and pressure control as well as the torque limitation of the A4VS… variable displacement pump are effected by an electrically controlled proportional valve (1). Via the actuating piston (2) of the pump, this valve determines the position of the swash plate (3).
The position of the swash plate is determined by a swivel angle sensor (4); the actual pressure value is recorded by a pressure transducer.
The actual torque value is calculated from the product of the actual pressure value and the actual swivel angle value. The controller software ensures by means of a minimum value generator that the controller corresponding to the working point is always active.
The sectional drawing shows the A4VS… variable displacement pump with HS5 control; the proportional valve (1) is controlled using the VT-HPC control electronics.
Notice for the HS5 control:
With de-energized proportional valve and pump with clockwise rotation and if the set pressure is available, the pump swivels to swivel angle α = 0 (A4VSO design) or α = –100% (A4VSG design).
Functional description of the control electronics
The VT-HPC (Hydraulic Pump Control) is a digital control system with integrated controller, optionally with programming according to IEC 61131. The internal PLC functionality is activated by plugging the SD card SD-HPC-PLC. It is not included in the VT-HPC scope of delivery and must be ordered separately.
The following controller functionalities are available:
- Pressure control
- Swivel angle/flow control
- Torque limitation
- Optional: Speed-variable function (n function)
This enables, amongst others, the following operating modes:
- Pressure/swivel angle control
- Pressure/flow control
Command value presetting is done via the bus interfaces (XF20/XF21 or XF30), via the analog interface (XG20) or, alternatively, via an internal PLC program.
The feedback information of the actual value signals to the superior control system is provided optionally either via the bus interfaces (XF20/XF21 or XF30) or the analog/digital interface (XG20).
The controller parameters are set via one of the two Ethernet interfaces (XF20/XF21) (integrated switch functionality)
The digital control electronics enable comprehensive monitoring functions/error detection including:
- Communication error
- Cable break for analog sensor inputs (4 … 20 mA)
- Short-circuit monitoring for analog/digital outputs
- Temperature of the integrated electronics
IndraWorks PC program
To implement the project planning task and to parameterize the VT-HPC, the user may use the IndraWorks DS operation tool. For the use of the PLC function, IndraWorks MLD is necessary:
- Project planning
- Comfortable management of all data on a PC
- Requirement: PC operating system at least Windows 7
Slot for one SD memory card
The following data may be saved:
- Parameter data
- Any other data
- Update of the speed-variable function (see Accessories)
Only SD and SDHC memory cards up to a size of 4 Gbyte with FAT32 formatting are supported. The card must already be inserted when the device is switched on, otherwise it will not be detected. It is recommended to use the Rexroth memory card (see Accessories).
- Component series 1X
- Control electronics for the A4VS axial piston pump with HS5 adjustment
- Function: Swivel angle, pressure control, torque limitation, master/slave
- Communication: Sercos, PROFINET RT, EtherCAT, EtherNET/IP, POWERLINK, optionally PROFIBUS, analog
- Parameterizable via standard Ethernet