ABB Compact control system replaces PLC AC700F

800F system. “It is easy for anyone to learn how to operate

the software and hardware. In contrast, it was practically impossible

to understand the standard program supplied by the

manufacturer together with the centrifuge.” Mr. Rohner also

sees clear advantages over other systems when it comes to

maintenance and faultfinding. Whereas with other manufacturers

faultfinding is only possible using a handheld device in

the field, Freelance 800F provides extensive analysis options

right in the control room. “Now I look at the status and can

see straight away where the error is. That is not possible that

simply in other systems.” This makes fault finding and maintenance

substantially easier.

Northam Platinum Ltd. is based in Johannesburg, South Africa,

and mines and produces precious metals. Convertors are

used to extract platinum from ore. These convertors are driven

using electrical motors. Until now, a PLC controlled the motors’

direct motor starters. This operating mode was not reliable

and efficient enough for Northam, as the motors thus operate

constantly at full output. That reduces the lifespan of the components

and causes higher repair and maintenance costs to

increase.

When the application was modernized and converted to frequency

converters to increase energy efficiency, the outdated

PLCs were to be replaced. Customer requirements were a

more compact controller, an improved presentation of alarms

and results and an excellent cost/benefits ratio.

Northam opted for the new AC 700F controller when replacing

PLCs for the converters. Northam has been using the Freelance

800F system to control its smelting furnaces and other applications

for many years and is convinced by the systems performance.

One AC 700F controller now regulates one variable-speed

drive. The motor output can be adjusted at any time to the

current operating requirements of the application, as frequency

converters can be simply driven by the controller. The adjustment

allows up to 50% of energy savings and processes can

be better controlled. The increase in efficiency resulting from

the intelligent speed control can be used in two ways: to increase

productivity or to keep production stable while simultaneously

reducing energy consumption.

Integration of the AC 700F controller into the existing Freelance

800F system and the easy engineering with just one engineering

tool, “Control Builder F” simplify commissioning and maintaining

of the entire application. The configuration is particularly

simple as the visualization is also created with Control Builder

F. Separate tools for programming the PLCs and to create

operator images are no longer needed. Technicians now only

need to handle a uniform engineering tool system wide. Production

data and information such as signal descriptions,

current and historical data, reports and detailed status information

can be recorded over several years in the information

management tool PGIM 800F.

As a result of its positive experience, Northam will modernize

additional converters and other small plants using the AC 700F

controller in the near future.