Product description

The TwinCAT Temperature Controller is a universally applicable PLC function block for monitoring and controlling a wide variety of temperature-dependent processes. The controller can be operated in

• automatic mode (closed loop) and
• manual mode (open loop).

The control value can be accessed in digital or analog form. The digital control value is pulse width modulated (PWM). A two-point or three-point output is also available. The control value is limited to the permitted maximum and minimum values.

The setpoint is also limited to permitted minimum and maximum values, and can also be ramped. A bit is available in the interface to the function block that provides easy switching from the setpoint to a standby setpoint. A soft start can be parameterized to support "heater baking". This involves the setpoint (optionally ramped) being initially set to a low value, remaining there for a certain time, then being changed to the true setpoint (again optionally ramped).

The actual value can be digitally filtered.

The control algorithm is PID-based. An additional pre-controller can be inserted in order to minimize overshoot.

The controller has a variety of parameterizable monitoring functions. There is

• tolerance band monitoring (two different tolerance bands),
• absolute value monitoring,
• encoder monitoring (open, backvoltage, reverse) and
• heating current monitoring (open, short circuit, leakage current).

There is an algorithm for determination of optimal controller parameters that greatly simplifies the process of commissioning the controller. This algorithm evaluates a jump and uses the inflectional tangent method to determine the maximum velocity and delay time of the section. This data allows a controller to be specified according to the rules of Chien, Hrones and Reswick. The parameters for the pre-controller are also determined here. If the controller parameters are already known, then the controller can also be operated using these externally supplied parameters. The controller parameters can be determined separately for the heating and cooling section. A corresponding sequence of the tuning process can be preselected. If no separate parameter set is determined for cooling, it is also possible to use the heating parameter set for the cooling section by means of a freely selectable scaling factor.

Commissioning the Controller in Stages.

Documentation of the function block and the required structures.