Ft int

Type Function module

Input IN	REAL (input signal)
K	REAL (multiplier)
RUN	BOOL (enable input)
RST	BOOL (Reset input)
OUT_MIN	REAL (lower output limit)
OUT_MAX	REAL (upper output limit)
Output OUT_MAX	REAL (upper output limit)
LIM	BOOL (TRUE if the output is at a limit)
	FT_INT is an integrator module which provides the integral of the input signal at the output. The input K is a multiplier for the output signal. Run switches the integrator on if TRUE and off when FALSE. RST (reset) sets the output to 0. The inputs OUT_MIN and OUT_MAX serve upper and lower limits for the output of the integrator. FT_INT works internally in microseconds and is thus fulfill also the requirements very fast PLC controller with cycle times under one millisecond.

| | A fundamental problem with integrator is the resolution.The output of type real has a resolution of 7-8 points. This will result in a calculated integration step of 1 at an output value of more than one hundred million (1E8). Thus the step can not be added up because it falls below the resolution limit of a maximum of 8 points in type Real. This limitation is important when using FT_INT. | | | For example, an input signal of 0.0001 would be at a sampling time of 1 millisecond and a baseline of 100000 to add a value of 0.0001 * 0.001 seconds = 0.000001 to the baseline of 100000, which inevitably results in the value of 100000 again, because the resolution of the data type Real can only collect up to 8. This should be considered especially if FT_INT should serve as a utility meter or similar applications. | | Structure diagram | |