Lease Automatic Custody Transfer (LACT)

For over 20 years, Willowglen has been at the forefront of the custody transfer flow computer business with innovative products that incorporate new technologies to push the limits of what is possible in a flow computer. Willowglen was among the first companies to offer a microprocessor-based flow computer. The innovation continues with the Unisen Flow Computer Complete LACT Package:

  • Up to 2 meters, BS&W, sampler
  • Ideal for measuring liquid flow
  • Integrated PLC functionality
  • Custody tickets by network printer or web server (web browser requires an external computer)
  • Provides card reader/4.3” HMI for gauger/driver input
  • Sample Arrangements: 16 AI, 2 pulse inputs, 16 DI, 8 DO
  • Modular and expandable I/O

The Unisen Flow Computer is your most advanced, scalable, and cost-effective choice.

Key Features

Truck Metering

The Unisen Flow Computer interfaces to standard liquid flow meters, and functions in a variety of configurations – swiping a card or utilizing an HMI to enter truck data and producing a ticket for the trucker and central office.

Card Reader

The Unisen Flow Computer is able to read truck ID from a card reader. All data can be verified by the user.


The Unisen Flow Computer has sampling routines built in; an external PLC is not required.

Electronic Ticketing

Unisen’s electronic ticketing can be easily adapted to the needs of your business.

Web Browser for Remote Maintenance

Standard web browser can be connected to the Ethernet port on the Unisen Flow Computer to configure or view its database or reports. No special software, hardware, or licenses needed.

Alarm, Event, Audit Logs

Maintenance, configuration, operator action, or field events are recorded in a log file. Each entry contains a time stamp, the change issuer, along with the old and new value.

Configurable Reports

By using one of the four Ethernet ports on the Unisen, reports can be set to automatically print directly from the flow computer itself (no need for an intermediate PC to do the printing). Alternatively, reports can be saved as files in PostScript or CSV file format. Any report can be recalculated (with audit).

Database Records

  • 1,000 Well Database Records
  • 1,000 Truck Database Records
  • 1,000 Meter Prove Records

Flexible Reporting and Tracking

  • Driver Authentication
  • Tracking filling levels for sample receiver
  • Repository for Drive Load Transactions
  • File based report delivery (FTP)

IEC Programming Environment

The Unisen Flow Computer allows customers to create their own PLC programs. These programs can be written in any of the five IEC 61131-3 languages including ladder logic.

  • ESD Valve Control
  • Ground Permissive

HMI – Operator Interface

An HMI features full graphic displays and keyboard for data entry or to view GSV. The 4.3” HMI can fit in older flow computer cutouts for upgrading purposes.

Upgrading Existing Flow Computers

Some 10+ year flow computer installations may need upgrading. To simplify upgrades, Willowglen provides a faceplate to directly fit older flow computer panel cut-outs.

Flexible Modbus Map

The Unisen flow computer has a flexible Modbus Map that can be easily configured with a Omni Software Modbus Map.


Technical Specifications

  • Flow computer: 4 Ethernet ports, 6 serial ports
  • Operating temperature: -40°C to 50°C (-40°F to 122°F)


The Unisen Flow Computer is compliant with API measurement standards.

Dimensions and Weight

(Including power supply module and I/O cards)

  • Size: 296mm x 166mm x 229mm (11.65in x 6.55in x 9.0in)
  • Weight: 2.72kg (6lbs)

Value-Added Services

  • Software Configuration
  • Panel Wiring
  • Factory Acceptance Testing
  • Supervise On-site Installation
  • On-site Configuration
  • Assist with On-site Commissioning
  • Ongoing Servicing and Support