Operating Process Examples of the Servo Function

Automatic Mode with Position Copy

Operation in automatic mode with copy position.

T_MOTOR = 25 s, T_MINI = 1 s and sampling period = 4 s

For each step, the operating principle is as follows.

Step	Operating principle
1	The deviation between OUT_MAN and RCPY is 20%. A pulse of 5 s (25 s x 20%) is generated on the RAISE output.
2	The deviation is 10%. A pulse of 2.5 s (25 s x 10%) is generated on the Raise output, without accounting for the second which remained from the previous pulse.
3	The deviation is –2%, which would correspond to a pulse of 0.5 s (25 s x 2%) on the LOWER output. As T_MINI equals 1 s, no pulse is generated (in contrast, the 0.5 s duration is stored.
4	The deviation is always -2%. The corresponding pulse (0.5 s) is added to the previously stored pulse (0.5 s) to give 1 s. As this duration is at least equal to T_MINI, the pulse is therefore applied to the LOWER output.

Automatic Mode without Position Copy

Operating in automatic mode without position copy.

T_MOTOR = 25 s and T_MINI = 1 s

In this case, the command variation value is taken into account each time the Servo function is operated.

For each step, the operating principle is as follows.

Step	Operating principle
1	The PID output variation is +20%. A pulse of 5 s (25 s x 20%) is generated on the RAISE output.
2	The PID variation is +2%, which would correspond to a pulse of 0.5 s. As this pulse is less than T_MINI (=1 s.),it does not affect the outputs.
3	This second PID output variation is +2%. In order to be calculated, the function adds this variation to the previous variation (which was below the minimum value), corresponding to a global variation of +4%. A pulse of 1 s (25 s x 4%) is generated on the RAISE output.
4	The PID output variation is -24%. A pulse of 6 s (25 s x 24%) is generated on the LOWER output.
5	Before completion of the following second, a further variation of +22% on the PID output restores the system to a global variation of –2%. As this variation corresponds to a pulse of 0.5 s (below T_MINI), the function ends by carrying out the minimum pulse of 1 s.

Manual Mode without Position Copy

In the case of operating in manual mode without copy position, the opening or closing bit moves to 1 during a period of time which corresponding to the command difference (proportional to period of opening time).

For example, T_MOTOR = 10 s. If the command moves from 30% to 40% then the RAISE output = 1 during 1 s (10 s x (40%-30%)).