1) byte–addressed (8 bit)
Byte addressable by the store identifier, identifier, a byte address combination of bytes. As VB100, its byte addressing mode as shown in the figure.
Byte addressing format: [region ID] [–identifier].[–byte address]
2) addressing (16 bit)
Addressed by the store identifier, identifier and byte the starting address combination. VW100, addressing mode as shown in the figure.
Address format: [region ID] [start address identifier].[bytes]
3) double word address (32 bit)
Double-word addressed by the store identifier starting address, two-character identifier and byte combinations. VD100, its double-word addressed, as shown in the figure.
Double word address format: [region ID] [two-character identifier starting address].[bytes]
For ease of use and the unification of data and memory cell length, S7-200 series, general storage unit has addressed, byte–addressable, addressing and Gemini addressed 4 addressing modes. When addressing, different ways of addressing cases use the same byte address as the start address, it indicates that the address space is different.
In S7-200, some special storage unit for storing data-bit addressing mode is not supported, mainly analog input/output, accumulators, timers, and the current value of the counter memory. Regardless of what mode of addressing and accumulator, will use 32-bit, analog unit addresses are even signs. In addition, timers, memory and the memory with the current value of the counter, belong to the same marking of device memory using the same address.