Siemens Simatic S7 Series System Manual

Special memory (SM) and system symbol names
D.9 SMB8-SMB19: I/O module ID and errors
S7-200 SMART
672 System Manual, 09/2015, A5E03822230-AC
D.9
SMB8-SMB19: I/O module ID and errors
SMB8 through SMB19 are organized in byte pairs for expansion modules 0 to 5.
The even-numbered byte of each pair is the module-identification register. These bytes
identify the module type, the I/O type, and the number of inputs and outputs.
The odd-numbered byte of each pair is the module error register. These bytes provide an
indication of any errors detected in the I/O for that module.
See also
SMW100-SMW114 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.