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Entry type: FAQ, Entry ID: 23451499, Entry date: 09/29/2014
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What is the meaning of the terms "sinking" (German: "P-lesend") and "sourcing" (German: "M-lesend") in digital modules of SIMATIC?

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  • Associated product(s)
There is a variety of terminologies for characterizing digital inputs and outputs; "P-lesend" and "P-schaltend" (PNP), "M-lesend" and "M-schaltend" (NPN) in German and sinking/sourcing in English.

Furthermore, you can characterize or order the digital inputs and outputs as follows:

  • the logical status
  • the electrical signal
  • the wiring and switching

The two tables below show the relationship between terminology and assignment:

Digital inputs (24V)
 

Terminology Logical status Electrical signal

Switching

P-lesend

Sinking input

Switch is located between DC24V and the module

1 (true) 24V


Fig. 01

0 (false) 0V (or open)
M-lesend

Sourcing input

Switch is located between the module and ground

1 (true) 0V
Fig. 02
0 (false) 24V (or open)

Table 01

Digital outputs (24V)
 

Terminology Logical status Electrical signal

Switching

P-schaltend

Sourcing output

PNP Transistor

Load located between the module and ground

1 (true) 24V


Fig. 03

0 (false) 0V (or open)
M-schaltend

Sinking output

NPN Transistor

Load located between DC24V and the module

1 (true) 0V
Fig. 04
0 (false) 24V (or open)

Table 02

The input and output modules of S7-300, S7-400, S7-1500, S7-1200 and ET 200S are P-lesend (sinking input) or P-schaltend (sourcing output). The exceptions are the modules listed below.
 

Overview of SIMATIC S7-300 modules
6ES7321-1BH50-0AB0 Sourcing inputs (M-lesend)
6ES7321-1BP00-0AB0 Sinking inputs (P-lesend) or sourcing inputs (M-lesend)
6ES7350-1AH03-0AB0 Sinking encoder inputs (P-lesend) or sourcing encoder inputs (M-lesend)
6ES7351-1AH02-0AE0 Sinking encoder inputs (P-lesend) or sourcing encoder inputs (M-lesend)
6ES7322-1BP50-0AA0 Sinking outputs (M-schaltend)
6ES7326-2BF40-0AB0 Sourcing outputs (P-schaltend) or sinking outputs (M-schaltend)
6ES7352-5AH00-0AE0 Sinking outputs (M-schaltend)
6ES7352-5AH01-0AE0
Overview of SIMATIC S7-400 modules
6ES7421-7DH00-0AB0 Sinking inputs (P-lesend) or sourcing inputs (M-lesend)
6ES7450-1AP00-0AE0 Sinking encoder inputs (P-lesend) or sourcing encoder inputs (M-lesend)
Overview of SIMATIC ET 200S modules
6ES7131-4BD51-0AA0 Sourcing inputs (M-lesend)
6ES7131-4BF50-0AA0 Sourcing inputs (M-lesend)
6ES7138-4DA04-0AB0 Sinking encoder inputs (P-lesend) or sourcing encoder inputs (M-lesend)
6ES7138-4DL00-0AB0 Sinking encoder inputs (P-lesend) or sourcing encoder inputs (M-lesend)
6ES7132-4BD50-0AA0 Sinking outputs (M-schaltend)
6ES7132-4BF50-0AA0 Sinking outputs (M-schaltend)
6ES7138-4FB02-0AB0 Sourcing outputs (P-schaltend) or sinking outputs (M-schaltend)
Overview of SIMATIC ET 200SP modules
6ES7138-6AA00-0BA0 Sinking encoder inputs (P-lesend) or sourcing encoder inputs (M-lesend)
6ES7131-6BF60-0AA0 Sourcing inputs (M-lesend)
6ES7132-6BF60-0AA0 Sinking outputs (M-schaltend)
Overview of SIMATIC S7-1200 modules
6ES7221-3BD30-0XB0 Sourcing inputs (M-lesend)
6ES7221-3AD30-0XB0 Sourcing inputs (M-lesend)
6ES7223-3BD30-0XB0 Sourcing inputs (M-lesend)
6ES7223-3AD30-0XB0 Sourcing inputs (M-lesend)
Overview of SIMATIC S7-1500 modules
6ES7521-1BH50-0AA0 Sourcing inputs (M-lesend)
6ES7550-1AA00-0AB0 Sinking encoder inputs (P-lesend) or sourcing encoder inputs (M-lesend)

 Table 03

Further Information
The technical data of the modules listed in Table 01 provides information about whether the inputs are sinking or sourcing and whether the outputs are sinking or sourcing. The technical data of the S7-1200 and S7-1500 modules is available in the manuals listed below.
 

Manual Entry ID
SIMATIC S7-1500/ET 200MP digital input module DI 16x24VDC SRC BA 59191844
SIMATIC S7-1200 Automation System 36932465

 Table 04

Security information
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http://www.siemens.com/industrialsecurity.