Frequency Input Secure Blending Controller - DCV Control

The 515 CB02 application is a secure blending controller measuring the volume flow in a main and process line using frequency flow inputs.

The main and process flows are used to determine the net volume flow. The operator can view the ratio of totals as well as the ratio of flowrates.

The control of the process flow is via a digital control valve. The flowrate deadband and control responsiveness can be adjusted to reduce wear on valves.

The instrument can be set to prompt for a valid ID-Tag before a delivery can commence. The valid ID-Tag also sets the pre-programmed target ratio % and is stored as a part of the logged transaction record.

CALCULATIONS

The total and flowrate are derived from accurately measured frequency and the number of recieved pulses.

volume = pulses/k-factor

volume flow = frequency/k-factor

The controller caters for blending points before and after the main flowmeter. The process flow is a ratio of the net (combined) flow (o-100% range).

Pflow
Ratio% = —————- × 100
Netflow