Siemens SIMATIC S7-1200 Manual page 335

Table A- 65 Transmitter and receiver
Technical data
Type
Common mode voltage range
Transmitter differential output voltage
Termination and bias
Optional termination
Receiver input impedance
Receiver threshold/sensitivity
Isolation
RS485 signal to chassis ground
RS485 signal to CPU logic common
Cable length, shielded
Baud rate
Parity
Number of stop bits
Flow control
Wait time
Table A- 66 Power supply
Technical data
Power loss (dissipation)
Current consumption (SM Bus), max.
Current consumption (24 VDC) max.
Easy Book
Manual, 03/2014, A5E02486774-AF
CB 1241 RS485
RS485 (2-wire half-duplex)
-7 V to +12 V, 1 second, 3 VRMS continuous
2 V min. at R = 100 Ω
L
1.5 V min. at R = 54 Ω
L
10K to +5 V on B, RS485 Pin 3
10K to GND on A, RS485 Pin 4
Short Pin TB to Pin T/RB, effective termination impedance is 127 Ω,
connects to RS485 Pin 3
Short Pin TA to Pin T/RA, effective termination impedance is 127 Ω,
connects to RS485 Pin 4
5.4K Ω min. including termination
+/- 0.2 V min., 60 mV typical hysteresis
500 VAC, 1 minute
1000 m max.
300 baud, 600 baud, 1.2 kbits, 2.4 kbits, 4.8 kbits, 9.6 kbits (default),
19.2 kbits, 38.4 kbits, 57.6 kbits, 76.8 kbits, 115.2 kbits,
No parity (default), even, odd, Mark (parity bit always set to 1),
Space (parity bit always set to 0)
1 (default), 2
Not supported
0 to 65535 ms
CB 1241 RS485
1.5 W
50 mA
80 mA
Technical specifications
A.9 Communication interfaces
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