Siemens SIMATIC S5-100U, System Manual

Page: 108 / 552

Addressing S5-100U
6.2 Digital Modules
Digital modules can be plugged into all slots (0 through 31).
Only two information states (“0” or “1”, OFF or ON) per channel can be transferred from or to a
digital module. The memory requirement is one bit.
Each channel of a digital module is displayed by a bit. This is the reason that every bit must be
assigned its own number. Use the following form for a digital address:
Figure 6-5. Configuration of a Digital Address
Bit number (channel number)
Byte number (slot number)
x . y
The “X.Y” address consists of the following two components:
• Byte Address X (Slot Number X)
- The byte address is the same as the number of the slot the module is plugged into.
• Channel Number Y (Bit Address Y)
- The channel number comes from the connection of the actuators or sensors to the terminals
of the terminal block. The assignment for the channel number and the terminal number is
printed on the frontplate of the module.
Example: Address Assignment
You are connecting a 2-wire BERO proximity limit switch to an 8 x 24-V DC digital input module
(6ES5 421-8MA11) at terminal 3. The other wire is routed to an L+ (positive supply voltage) termi-
nal block (see section 3.2 for wiring). The module is plugged into slot 3.
This defines the address used by the control program to evaluate the signal states of the BERO.
• The byte address is 3 since the module is plugged into slot 3.
• As shown on the frontplate, channel number 1 is used.
• The complete address for the BERO switch is 3.1.
Note
You can address 4-channel digital modules only with channel numbers 0 through 3. The
channel numbers 4 through 7 printed on the frontplate are relevant only for the ET 100U
system.
6-4
EWA 4NEB 812 6120-02b