PLC Simatic S5

Addressing/Address Assignments

Address Structure

Digital modules are addressed by bit and analog modules are addressed by byte or word. So, their have different formats

Digital Modules Address

One bit represents a channel on digital module. When you assign the address, remember these:

· The CPU program memory is divided into different address areas

· Number individual bytes consecutively in relation to start address of the relevant address area

· Number the eight bits of each byte consecutively

Bit No. (Channel Number)

0 . 5

	Byte No.

Analog Module Address

Each channel of an analog module is represented by two bytes (=one word). A analog channel address is thus represented by the number of the high-order byte.

Slot Address Assignments

You can establish addresses for S5-115U modules in the following two ways:

· Fixed slot addressing

Each slot has a fixed address under which yopu can reference the module plugged into that slot

· Variable slot addressing

The user can specify an address for each slot

Fixed slot and variable slot addresses are relevant only for modules of block design. The addresses of intelligent I/O modules and modules of ES 902 design (S5-135U/155U) are set on the modules themselves. In this case, the address need not be set on the IM 306.