Bus line
Remarks
Commonly used telephone cables with PE insulation and a
core diameter of > 0.8 mm are usually sufficient.
Cables with PVC core insulation and core diameter of
0.8 mm can be used up to a length of approx. 250 m. In this
case, the bus terminating resistor is approx. 100
Ω
.
Cable Lengths
The maximum possible cable length of a serial connection subnet within a segment depends on
the baud rate (transmission rate).
COM1 - RCOM:
Baud rate
Maximum cable length
2.4 kBaud to 19.2 kBaud
On request
COM2 - CONSOLE:
Baud rate
Maximum cable length
19.2 kBaud
On request
Bus Termination (RS-485 only)
The line ends of the bus segment must be equipped with bus termination resistors. Normally,
these resistors are integrated in the interface connectors.
Master at the bus line end,
pull-up and pull-down activated,
bus termination 120 Ohms
Slave within
the bus line
Slave at the bus line end,
bus termination 120 Ohms
1
2
3
4
RxD/TxD-P
RxD/TxD-N
1
2
3
4
1
2
3
4
120
Ohms
120
Ohms
Term. P
Term. N
1.3.2.3
State LEDs
LED
Color
State
Description
PWR
Green
ON
Voltage is present
OFF
Voltage is missing
RDY
Yellow ON
Communication module is ready
Flashes
cyclically
Event queue blocked (slave devices only)
OFF
Hardware defective
RUN
Green
ON
Normal operation
Device Specifications
Communication Modules (AC500 Standard) > CM574-RCOM for RCOM/RCOM+
2019/04/17
3ADR010121, 13, en_US
97