System Overview of the ABB Freelance DCS

The Freelance DCS provides both, operator level and process level. The operator or HMI level contains the functions for operation, process monitoring, archives and logs, trends and alarms. Open-loop and closed-loop control functions are processed in the controllers, which communicate with actors and sensors in the field.

Freelance operator level
Freelance Operations (DigiVis) provides HMI functionality and runs on a simple PC-environment under Microsoft Windows. It supports dual-monitor operation to stay continuously tuned with essential information like the alarm list, while inspecting at the same time for example the progress of a sequential function chart, trend archives, or the system display with extended diagnostics.

Freelance Engineering
The Freelance engineering station is used to configure and commission the system including the operator interface. Usually, portable equipment such as laptops, which allow configuration both in the office and on site, can be used.

The Freelance process level
A Freelance system can consist of between one and several AC 700F, AC 800F or AC 900F controllers and can be extended with different types of I/O units. You have the option of configuring your system either standard or fully redundant. The connection to the Freelance control network is achieved via Ethernet.

ABB Freelance DCS Benefits

  • Scalable system structure: The Freelance DCS can be easily scaled up from a small system of a few I/Os to a large system of up to thousands of I/Os. Expansion can be done with minimal engineering effort.
  • Reliability: The technology has proven its worth in industrial use over several years and meets the toughest requirements regarding availability. The hardware can be structured redundantly at all levels. This includes the redundant fieldbus modules, redundant fieldbus lines as well as network and controller redundancy.

We focus on industrial automation and process instrument over 20 years

Freelance comes with three different types of controllers, AC 700F, AC 800F and its latest Freelance controller – the AC 900F. This controller truly extends the hardware portfolio of Freelance distributed control system.

AC 900FImage result for AC 900F
– SD card support
– Typically around 1,500 I/Os supported with CPU PM 902F
– Up to 400 I/Os supported with CPU PM 901F (Lite)
– G3 compliant as standard
– Redundancy option for high availability
– AC 900F Standard (PM 902F): Four (4) built-in Ethernet ports supporting Modbus TCP or 60870-5-104 Telecontrol protocol
– AC 900F Lite (PM 901F): Three (3) built-in Ethernet ports supporting Modbus TCP or 60870-5-104 Telecontrol protocol
– Two (2) serial ports supporting Modbus RTU or IEC 60870- 5-101 Telecontrol protocol
– Optional PROFIBUS master modules (up to two) providing integrated line redundancy
– Optional one CAN Bus communication interface for connection of Freelance Rack I/O
– Direct connection of I/O modules (as many as 10), including modules combining inputs and outputs in just one module can reduce footprint and costs.
– I/O modules can also be connected remotely via PROFIBUS


AC 800FImage result for AC 800F
– The outstanding feature is it can be equipped with a set of fieldbus modules, covering all major fieldbuses used in process automation.
– Option to run controllers either redundantly (CPU redundancy, fieldbus module redundancy) or non-redundantly.

– Fieldbus-compliant components such as remote I/O, field devices, and network components can be used.
– Optional G3-compliant
– A single controller can typically support around 1,000 I/Os


AC 700FImage result for AC 700F
– Typically supports around 300 I/O signals per AC 700F controller.
– This PLC-like controller comes with a very small footprint.
As many as eight (8) S700 direct I/O modules can be plugged to the right of the controller module.
– The connection to the Freelance control network is via Ethernet as for all other controllers. As an alternative to remote I/Os, AC 700F can be placed directly in the field, offering a very flexible and cost-effective solution for an “intelligent” I/O station.
– I/O modules can also be connected remotely via PROFIBUS. This allows for high flexibility in installation.
– SD card support
All three controller types can be used side by side within a project and can easily communicate with each other via the Ethernet based control network. The engineering is performed with one engineering tool, Freelance. All function blocks and pre-engineered functions are available for all controllers in the same way.