Siemens Simatic S7 Series System Manual

Program instructions
7.6 Counters
S7-200 SMART
System Manual, 09/2015, A5E03822230-AC
223
HSC operating rules
● Before you use a high-speed counter, you must execute the HDEF instruction (High-
Speed Counter Definition) to select a counter mode. Use the first scan memory bit,
SM0.1 (this bit is ON for the first scan and OFF for subsequent scans) to execute HDEF
directly, or call a subroutine that contains the HDEF instruction.
● You can use all counter types with or without a reset input.
● When you activate the reset input, it clears the current value and holds it clear until you
deactivate the reset input.
See also
High-speed counter programming examples (Page 226)
High-speed counter initialization sequence examples (Page 238)
Noise reduction for high-speed inputs (Page 224)

Siemens Simatic S7 Series Specifications

General

CPU	Varies by model (e.g., S7-300, S7-400, S7-1200, S7-1500)
Communication Interfaces	PROFIBUS, PROFINET, Ethernet, MPI
Programming	TIA Portal, STEP 7
Programming Languages	LAD, FBD, STL, SCL, GRAPH
I/O Modules	Digital, Analog, Specialty modules available
Operating Temperature	0°C to 60°C (standard models)
Mounting	DIN rail mounting
Operating Voltage	24V DC or 120/230V AC (varies by model)
Protection Class	IP20 (standard models)
Memory	Varies depending on the S7 model. Includes work memory (RAM) for program execution, load memory (EEPROM or Flash) for program storage, and system memory for operating system functions. Memory sizes range from kilobytes to megabytes.