Siemens Simatic S7 Series System Manual

PLC concepts
4.2 Accessing data
S7-200 SMART
74 System Manual, 09/2015, A5E03822230-AC
Using an offset to access data
This example uses LD10 as a pointer to the address VB0. You then increment the pointer by
an offset stored in VD1004. LD10 then points to another address in V memory (VB0 +
offset). The value stored in the V memory address pointed to by LD10 is then copied to
VB1900. By changing the value in VD1004, you can access any V memory location.
Table 4- 20 Example: Using an offset to read the value of any V memory location
LAD
STL
Load the starting address of the V
memory to a pointer.
Add the offset value to the pointer.
Copy the value from the V memory
location (offset) to VB1900
Network 1
LD SM0.0
MOVD &VB0, LD10
+D VD1004, LD10
MOVB *LD10, VB1900

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.