Chapter 9
183
Logic programming – Function blocks
For restrictions to this rule that apply in forward/backward locked mode see below.
5. If the release time has expired and no transition to inch mode has occurred, the
function block will transit back to Waiting for start mode and a complete start
sequence is required again.
6. The duration of the inch mode is not limited. It will be stopped if the High input (Inch
forward or Inch backward) becomes Low again. In this case the Enable output
and the Forward active or the Backward active output will become Low again.
The inch mode will also be stopped if both inputs (Inch forward and Inch
backward) become High at the same time. After the inch mode has been stopped,
the release time starts again. This means that another rising edge on the Inch
forward or on the Inch backward input will restart the inch mode immediately
without a new start sequence. If the release time has expired and no transition to
inch mode has occurred, the function block will transit back to Waiting for start
mode and a complete start sequence is required again.
7. The inch mode will also be stopped by a falling edge on the Reset input or on the
Stop input. In this case, the function block will transit back to Waiting for start mode
and a complete start sequence is necessary again.
Parameters of the function block
Parameter Possible values
Direction switching Locked
Not locked
Waiting time
1 to 60000 ms in steps of 10 ms. The value has to be greater
than the logic execution time.
Release time
1 to 600000 ms in steps of 10 ms. The value has to be greater
than the logic execution time.
Signal time
0 to 6000 ms in steps of 10 ms. If the value is not 0, it has to be
greater than the logic execution time, but smaller than the
Waiting time.
Impulse time
0 to 60000 ms in steps of 10 ms. If the value is not 0, it has to be
greater than the logic execution time, but smaller than the
Release time.
Direction switching
This parameter determines if it is possible to switch between the forward and
backward direction with or without execution of the complete start sequence. If the
setting Not locked is configured it is possible to initiate the start sequence with one of
the inputs (e.g. Inch forward) and confirm the start sequence with the other input (e.g.
Inch backward). In Not locked mode, it is also possible to switch the direction of the
inch mode without the execution of the complete start sequence.
The setting Locked means that the start sequence must be confirmed (during the
release time) with the same input (Inch forward or Inch backward) that has triggered
the start sequence. A rising edge on the other input will restart the Waiting time instead.
It is also not possible to switch between directions in inch mode. If the direction shall be
changed a complete start sequence must be executed (see also Figure 173).
Note
Table 80:
Parameters of the Start
warning function block
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