Siemens Metro 21 M216KA Operator's Manual page 324

The 1COUNT40kHz Counter Module
Behavior of the
Output
Output disabled
The output remains deactivated and is not affected by the events comparison value, zero-
crossing, overflow or underflow.
Active from compar-
ison value to over-
flow
*
The output is activated when the counter is in the range between the comparison value n and
overflow. When the counter is set to a value between comparison value and overflow, the
output is activated.
Active from compar-
ison value to under-
flow
*
The output is activated when the counter is in the range between the comparison value n and
underflow. When the counter is set to a value between comparison value and underflow, the
output is activated.
Active at comparison
value counting up-
ward
*
The output is activated for the length of the pulse duration when the comparison value is
reached counting upward.
Active at comparison
value counting
downward
*
The output is activated for the length of the pulse duration when the comparison value is
reached counting downward.
Active at comparison
value counting up-
ward/downward
Underflow Comparison value Overflow
The output is activated for the length of the pulse duration when the comparison value is
reached regardless of the direction of counting.
13-10
You can set one of 6 possible responses for the output when the comparison
value is reached. The alternatives are shown in the table below.
Behavior of the Output
Underflow
Underflow
Underflow
Underflow
Underflow
Upward
t
* Note the conditions overleaf
= output active
t = pulse duration
ET 200L, ET 200L-SC and ET 200L-SC IM-SC Distributed I/O Device
Comparison value Overflow
Comparison value Overflow
Comparison value Overflow
t
Comparison value
t
Comparison value Overflow
t
Underflow Comparison value Overflow
Overflow
Downward
EWA 4NEB 780 6009-02c