Siemens SIMATIC S7-300 FM 350-1, Manual

Page: 114 / 198

Operating Modes, parameters and commands
7.3 Count modes
FM 350-1 Counter module
114
Manual, 05/2011, A5E03648639-01
W
W
&03B9
&03B9
'2
&RXQWHUOHYHO
Figure 7-18 At the start of the counting process, V2 < V1
Pulse Duration
You can set a pulse duration in order to adapt to the actuators (contactors, actuators, etc)
used in your process. The pulse duration indicates how long outputs DO0 and DO1 are
active when a comparison value is reached.
If main count direction up or main count direction down is set, then the pulse duration is only
active in the main count direction.
If no main count direction is set, then the pulse duration can be active in both counting
directions.
The pulse duration starts when the output is set. The pulse duration inaccuracy is less than
1 ms.
You can specify a value between 0 and 500 ms for the pulse duration. This value applies to
both outputs together.
If the pulse duration = 0 ms, the output is set when the comparison value is reached and is
reset at the next count pulse.
The default value for the pulse duration is 0.
Note
If you set the pulse duration = 0 ms, the output remains active until the counter level is equal
to the comparison value.
Control pulses may be lost at the outputs if the time interval between the count pulses is less
than the switching times of the digital outputs (up to 300 µs).
You should therefore make sure that the interval between the count pulses is greater than
the switching times of the digital outputs.