The 515 BC01 application is a dual stage batch controller for reliable measurement of pre-set quantities using a volumetric frequency or analogue input. Used as a single or dual stage controller it is suitable for fast batch applications.
It provides the operator with clear local readout and can be controlled via communications in more automated systems. There is quick access to commonly used pre-set values directly from the front panel if access has been authorized. Automatic overrun compensation caters for system delays, such as valve closure, for precise volumes.
The instrument is compatible with a wide range of flowmeter frequency outputs, including millivolt signals, reed switches, pulse, Namur proximity switches and analogue signals. Inputs can be scaled, filtered, and have non-linear correction applied. Square law and cut-off points can also be applied to the analogue input.
If using the frequency input, 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
If using the analogue input, to derive the flow rate the input is normalised to a value (A) between 0 and 1.
volumeflow = (Vƒmax-Vƒmin) A = Vƒmin
Volume = ∫(volumeflow . Δt)
Automatic overrun compensation calculates the new valve closure point to ensure correct delivery by averaging the overrun amount from the last three complete batches.
The overrun compensation value is valid for a new pre-set value provided the stored overrun is less than 20% of the new pre-set.
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