High-Speed Counter Instructions - Siemens SIMATIC S7-200 System Manual

S7-200 Programmable Controller System Manual

High-Speed Counter Instructions

High-Speed Counter Definition
The High-Speed Counter Definition instruction (HDEF)
selects the operating mode of a specific high-speed counter
(HSCx). The mode selection defines the clock, direction,
start, and reset functions of the high-speed counter.
You use one High-Speed Counter Definition instruction for
each high-speed counter.
Error conditions that set ENO = 0
H 0003 (input point conflict)
H 0004 (illegal instruction in interrupt)
H 000A (HSC redefinition)
High-Speed Counter
The High-Speed Counter (HSC) instruction configures and
controls the high-speed counter, based on the state of the
HSC special memory bits. The parameter N specifies the
high-speed counter number.
The high-speed counters can be configured for up to twelve different modes of operation. See
Table 6-26.
Each counter has dedicated inputs for clocks, direction control, reset, and start, where these
functions are supported. For the two-phase counters, both clocks can run at their maximum
rates. In quadrature modes, you can select one times (1x) or four times (4x) the maximum
counting rates. All counters run at maximum rates without interfering with one another.
Error conditions that set ENO = 0
H 0001 (HSC before HDEF)
H 0005 (simultaneous HSC/PLS)
Table 6-25 Valid Operands for the High-Speed Counter Instructions
Inputs/Outputs
HSC, MODE
N
Refer to the Programming Tips on the documentation CD for programs that use high-speed
counters. See Tip 4 and Tip 29.
Programming
Tips
High-speed counters count high-speed events that cannot be controlled at S7-200 scan rates.
The maximum counting frequency of a high-speed counter depends upon your S7-200 CPU
model. Refer to Appendix A for more information.
Tip
CPU 221 and CPU 222 support four high-speed counters: HSC0, HSC3, HSC4, and HSC5.
These CPUs do not support HSC1 and HSC2.
CPU 224, CPU 224XP, and CPU 226 support six high-speed counters: HSC0 to HSC5.
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Data Types Operands
BYTE Constant
WORD Constant