Siemens Simatic M7-400 Reference Manual page 494

M7-400 Expansions
Table 12-7 MSM 478 Parallel Port, Socket X1 (25-Pin Sub D Socket)
Pin
1 /STROBE
2 Data 0
3 Data 1
4 Data 2
5 Data 3
6 Data 4
7 Data 5
8 Data 6
9 Data 7
10 /ACK
11 BUSY
12 PE
13 SLCT
14 /AUTO FEED
15 /ERROR
16 /RESET
17 /SLCT IN
18 GND
19 GND
20 GND
21 GND
22 GND
23 GND
24 GND
25 GND
Note
Operational ground (GND signal) at the COMa or COMb ports is referenced to
internal ground.
Suitable measures may be required on the process side to avoid ground loops.
12-24
Meaning
S7-400, M7-400 Programmable Controllers Module Specifications
Direction
Input/output
Input/output
Input/output
Input/output
Input/output
Input/output
Input/output
Input/output
Input/output
Input
Input
Input
Input
Output
Input
Output
Output
–
–
–
–
–
–
–
–
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