49
Powers
TM
IntelliStation BAS Integration Manual
Modbus
®
Specifications
Communication Protocol Modbus over RS485
Physical Layer RS485 Two-Wire plus Signal Ground
Baud Rate 2400, 9600, 19200, 38400, 57.6k, 115k)
(default 19200 bps)
Recommended Cable 18 AWG Shielded Twisted-Pair (STP)
Transmission Mode RTU or ACSII (default RTU)
Maximum Cable Length Without terminating resistors
- 115,000 baud --> 177 m (580 ft)
- 57,600 baud --> 353 m (1,158 ft)
- 19,200 baud --> 1,000 m (3,280 ft)
- 9,600 baud --> 1,000 m (3,280 ft)
- 2,400 baud --> 1,000 m (3,280 ft)
With 2 x 120 Ohm resistors
- 115,000 baud --> 1,000 m (3,280 ft)
- 57,600 baud --> 1,000 m (3,280 ft)
- 19,200 baud --> 1,000 m (3,280 ft)
- 9,600 baud --> 1,000 m (3,280 ft)
- 2,400 baud --> 1,000 m (3,280 ft)
Start Bit 1 Bit
Data Length 8 Bits for RTU Mode
7 Bits for ACSII Mode
Parity None (2 Stop Bits)
Even (1 Stop Bit)
Odd (1 Stop Bit)
(default Even)
Addressing 1 to 247 (default 1)