Serial interface Pin Signal
4 A2
internally connected to A1
5 B2
internally connected to B1
No. Protocol Description
1 Modbus Modbus RTU, master or slave
2 CAA SerialCom Support for blocks contained in the CAA_SerialCom.lib library
Bus line
Construction 2 cores, twisted, with common shield
Conductor cross section > 0.22 mm² (24 AWG)
Twisting rate > 10 per meter (symmetrically twisted)
Core insulation Polyethylene (PE)
Resistance per core < 100 Ω/km
Characteristic impedance ca. 120 Ω (100 Ω...150 Ω)
Capacitance between the cores < 55 nF/km (if higher, the max. bus length must be reduced)
Terminating resistors 120 Ω ¼ W at both line ends
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.
The maximum possible cable length of a serial connection subnet within a segment depends on
the transmission rate.
RS-485 for point-to-point or bus connection:
Parameter Value
Transmission rate 9.6 kbit/s to 115.2 kbit/s
Maximum cable length On request
The line ends of the bus segment must be equipped with bus terminating resistors. These
resistors are integrated in the module TA5142-RS485. The pull-up and pull-down settings must
also be made on the circuit board of the module.
Protocols
Bus cable
Cable length
Bus termination
Processor modules > AC500-eCo
2022/01/31 3ADR010278, 3, en_US 85
To Next Page
Loading...
