Siemens Simatic S7 Series System Manual

Libraries
9.3 Modbus library instructions
S7-200 SMART
452 System Manual, 09/2015, A5E03822230-AC
Holding register addresses greater than 49999
Modbus holding addresses are within the range of 40001 to 49999. This range is adequate
for most applications but there are some Modbus slave devices with data mapped into
holding registers at a higher address range.
The MBUS_MSG instruction allows an additional range for the parameter
Addr
to support an
extended range of holding register addresses at addresses 400001 to 465536.
For example: to access holding register 16768, the
Addr
parameter of MBUS_MSG should
be set to 416768.
The extended addressing allows access to the full range of 65536 possible addresses
supported by the Modbus protocol. This extended addressing is only supported for holding
registers.

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.