Siemens SIMATIC S7 System Manual page 265

HDEF instruction sets the counting mode
The HDEF instruction assigns HSC counter mode. The following table shows the physical
inputs assigned for clock, direction control, and reset functions. The same input cannot be
used for two different functions, but you can use any input not being used by the present
mode of its high-speed counter for another purpose. For example, if the present mode of
HSC0 is mode 1, which uses I0.0 and I0.4; then you can use I0.1, I0.2, and I0.3 for edge
interrupts, HSC3, or motion control inputs.
Note
All counting modes of HSC0 always use I0.0 and all counting modes of HSC2 always use
I0.2, so you cannot use these inputs for other purposes when these counters are in use.
Mode Description
0
1
3
4
6
7
9
10
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
HSC0
HSC1
HSC2
HSC3
HSC4
HSC5
Single-phase counter with internal direction
control
Single-phase counter with external direction
control
Two-phase counter with 2 clock inputs
AB quadrature phase counter
Program instructions
Input assignment
I0.0 I0.1
I0.1
I0.2 I0.3
I0.3
I0.6 I0.7
I1.0 I1.1
Clock
Clock
Clock Direction
Clock Direction
Clock Up Clock Down
Clock Up Clock Down
Clock A Clock B
Clock A Clock B
7.6 Counters
I0.4
I0.5
I1.2
I1.3
Reset
Reset
Reset
Reset
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