Operating mode

Selecting the operating modes

There are three operating modes, which are selected via the inputs MAN and HALT.

Operating mode	MAN	HALT
Automatic	0	0
Manual mode	1	0 or 1
Halt	0	1

Automatic operating mode

In the automatic mode, the function block operates according to the following rules:

If...	Then...
	the current X value is transferred to the buffer, and the oldest X value in the buffer is placed on the output Y. If a cycle time is greater than T_DELAY / 128, a resolution of less than 128 will result, causing a systematic error leading to double storage of some X values. (see the following Example).
	not all X values can be stored in the buffer. In this case the X value is not saved in some cycles, and Y remains unchanged in these cycles.

Example of automatic mode

In the example the following values are accepted:

Cycle time = 100 ms

T_DELAY = 10 s

tin = T_DELAY / 128 = 78 ms

As the reading time tin is shorter than the cycle time, each X value is transferred to the buffer. On the fourth execution of the function block (after 400 ms) the X value is saved twice rather than once (as 3 x 78 = 312 and 4 x 78 = 390).

Manual mode

In manual mode the manual value YMAN is consistently transferred to the control output Y. The internal buffer is charged with the manual value YMAN. The buffer is marked as charged (READY =1).

Halt mode

The output Yis held at the last calculated value in Halt mode. The internal buffer still continues to operate as in automatic mode.