Technical specifications
A.16 Communication interfaces
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
1541
RS232, RS422, and RS485
A.16.4.1
CB 1241 RS485 specifications
Note
To use this CB, your CPU firmware must be V2.0 or higher.
Table A- 245 General specifications
Dimensions W x H x D (mm)
Table A- 246 Transmitter and receiver
RS485 (2-wire half-duplex)
Common mode voltage range
-7 V to +12 V, 1 second, 3 VRMS continuous
Transmitter differential output voltage 2 V min. at R
L
= 100 Ω
L
Termination and bias 10K to +5 V on B, RS485 Pin 3
10K to GND on A, RS485 Pin 4
Optional termination 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,
5.4K Ω min. including termination
Receiver threshold/sensitivity +/- 0.2 V min., 60 mV typical hysteresis
Isolation
RS485 signal to chassis ground
RS485 signal to CPU logic common
707 V DC (type test)
Baud rate 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
Parity No parity (default), even, odd, Mark (parity bit always set to 1),
Space (parity bit always set to 0)