Siemens Simatic S7 Series System Manual

Special memory (SM) and system symbol names
D.10 SMW22-SMW26: Scan times
S7-200 SMART
System Manual, 09/2015, A5E03822230-AC
673
D.10
SMW22-SMW26: Scan times
SMW22, SMW24, and SMW26 contain information on the scan time. You can read the last
scan time, minimum scan time, and maximum scan time (millisecond values).
Table D- 7 SMW22-SMW26 PLC scan times
S7-200 SMART
symbol name
SM address
Description
Last_Scan
SMW22
Scan time of the last scan.
Minimum_Scan SMW24 Minimum scan time recorded since entering the RUN mode or since resetting these
values from the PLC Information dialog.
Maximum_Scan SMW26 Maximum scan time recorded since entering the RUN mode or since resetting
these values from the PLC Information dialog.
D.11
SMB28-SMB29: Signal board ID and errors
SMB28-SMB29 byte addresses store the signal board type and error status.
See also
SMW100-SMW110 System alarm codes (Page 684)

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.