The 515 BF01 application is a batching controller for delivery of preset quantities at preset flowrates using a volumetric frequency input. Batch control can operate in preset or on-off modes, while flow control can be set to local (manual) or PI loop mode.
This application provides the operator with clear local readout including flowrate deviation and can be controlled via communications in more automated systems. There is quick access to commonly used preset values directly from the front panel if access has been authorized.
The PI control of the process flow is via a 4-20mA proportional valve or pump controller. It has integral wind- up protection, a deadband, output hold and ramp time that can be programmed to reduce wear on valves and actuators and provide for bumpless operation.
The total and flowrate are derived from accurately measured frequency and the number of received pulses.
volume = pulses / k-factor
volume flow = frequency / k-factor
Automatic overrun compensation calculates the new valve closure point to ensure correct delivery by averageing the overrun amount from the last three complete batches.
The overrun compensation value is valid for a new preset value provided the stored overrun is less than 20% of the new preset.