Frequency Input Batch/Ratio Controller, Tailored for Volumetric Flow Meters

The 515 BR01 application is a batching process controller for delivery of preset quantities at preset ratios using volumetric frequency inputs. Batch control can operate in preset or on-off modes, while flow control can be set to various loop control modes.

The process controller 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 authorised.

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.

CALCULATIONS

There are three types of control modes in which the process flow is dependent on the main flow. These are RATIO, BLEND-1 and BLEND-2 modes where the relationship between the flows are as follows:

Ratio Control Mode.
The process flow is a ratio of the main flow (0 to 400% range).

Pflow
Ratio% = —————- × 100
Mflow

Blend Control Modes.
These modes cater for blending points before and after the main flowmeter. The process flow is a ratio of the net (combined) flow (0 to 80% range).

Pflow
Ratio% = —————- × 100
Netflow

Displayed Information

The front panel display shows the current values of the input variables and the results of the calculations. A list of the variables for this application and their type (total or rate) is shown at the end of this document.
The instrument can be supplied with a real-time clock for storage of up to 1000 transactions with time and date stamps.

Communications

There are two communication ports available as follows:

• COM-1 RS-232 port
• COM-2 RS-485 port (optional) or Ethernet (optional)

The ports are available for remote data reading, printouts and for initial application loading of the instrument.

Isolated Outputs

The opto-isolated outputs can be configured to retransmit any main menu variable or provide various error/control signals (flow error, pump control, end-of-batch, etc.). One output is standard, a second output is available as an option.

Relay Outputs

The relay outputs 1 and 2 are used to control the flow of product for each delivery. These contacts are normally open and can be used to drive external relays, valves,pump circuits etc. The advanced option provides another two relays that can be used as fully programmable alarms for any rate type variable.

Software Configuration

The instrument can be programmed to suit the particular application needs and the flexible I/O can be assigned as required. Program settings can be changed either via the front panel (depending on assigned access levels) or via the 500 Series Program Manager (500-PM software).
The instrument stores all set-up parameters, totals and logged data in non-volatile memory with at least 30 years retention.

For more information on Contrec’s 515 range of Batch Ratio Controllers, please click on the link.