Siemens installation manual Parallel Wiring of Digital S7-400 Outputs

Wiring the S7-400

4.8Parallel Wiring of Digital S7-400 Outputs

Parallel Wiring of a Digital Output with Different Rated Load Voltages

The parallel wiring of a digital output (rated load voltage 1L+) with another digital output (rated load voltage 2L+) or a rated load voltage 3L+ is only possible using series diodes.

1 L+ 2 L+ 3 L+

Figure 4-5 Parallel Wiring of a Digital Output with Different Rated Load Voltages

Parallel Wiring of a Digital Output with Identical Rated Load Voltages

If the L+ supplies of the digital output modules and the L+ voltage connected in parallel to the output are always the same (difference < 0.5 V), there is no need to use diodes, see figure 4-6.

L+

Figure 4-6 Parallel Wiring of a Digital Output with Identical Rated Load Voltages

4-12	Automation System S7-400	Hardware and Installation
		A5E00850741-01