Siemens Simatic S7 Series System Manual

Program instructions
7.6 Counters
S7-200 SMART
System Manual, 09/2015, A5E03822230-AC
233
Reset operation
The operation of reset shown in the following figure applies to all modes that use the reset
input. In the figure below, the reset operation is shown with the active state assigned as the
high level.
HSC reset
HDEF instruction sets the reset active level and counting rate
HSC0 and HSC2 counters have two control bits that are used to configure the active state of
the reset and to select 1x or 4x counting modes (AB quadrature phase counters only). These
bits are located in the HSC control byte for the respective counter and are only used when
the HDEF instruction is executed. These bits are defined in the following table.
Note
You must set these two control bits to the desired state before the
HDEF instruction is
executed. Otherwise, the counter takes on the default configuration for the counter mode
selected.
Once the HDEF instruction has been executed, you cannot change the counter setup unless
you first place the CPU in STOP mode.

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.