Hardware Interface - Siemens SIMEAS P 7KG7750 Manual

4.2

Hardware Interface

Bus connection 9-pole D-SUB outlet
Table 4-1
Protocol semi-duplex
Max. line length 1000 m / 3300 ft.
Insulation level AC 500 V
Bus termination Bus termination via bus plug with integrated terminating resistors.
Figure 4-1 Recommended external termination circuit with open-line fail-safe
Power Meter, SIMEAS P 7KG7750/55, Manual
E50417-B1076-C375-A3, Release 01.2009
Pin Signal
1 Shield Shield / Operational ground
2 - -
3 A RS485 connection pin A
4 RTS Directions control
5 GND Data transmission level (ground towards +5 V
EXT
6 +5 V Supply voltage for terminating resistors (DC +5 V, max. 100 mA)
EXT
7 - -
8 B RS485 connection pin B
9 - -
Pin assignment of the bus connector (D-SUB outlet)
A
B
Meaning
+5 V
EXT
390 Ohm
220 Ohm
390 Ohm
GND
EXT
Technical Data
)
EXT
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