Wiring the routers - SmartIntego specifications
You have several options for connecting the routers (SI.GN.CR) with each other. The following table gives an overview of the advantages and disadvantages of the connection options described here. The wiring options are sorted in descending order (recommendation).
Power supply units in the middle of the bus required | Wiring from bus terminal to Vin ext. and GND ext. required | Problems resulting from voltage drop | |
Separate power supply units for bus participants | yes | no | unlikely |
Daisy-chaining through Vin ext. and GND ext. | no | yes | unlikely (if high operating voltage is applied) |
Daisy-chaining through Vin and GND | no | no | possible |
The shown wiring options are not a complete list of all wiring options. Further options are possible!
Separate power supply units for bus participants
With this variant, each router (SI.GN.CR) is supplied with its own power supply unit at the external power supply connection (Vin ext. and GND ext.) (power supply unit optionally available, see Technical specifications). This means that no power supply is transmitted via the long RS-485 bus cable, only signals. As a result, only little current and voltage drop flows in the RS-485 bus line and the associated problems are minimised.
In addition, one wire in laid cables is saved because the supply voltage no longer has to be transmitted through the RS-485 bus line.
Loop through Vin ext. and GND ext.
With this variant, each router (SI.GN.CR) is supplied with the same power supply unit at the external power supply connection (Vin ext. and GND ext.). This makes high operating voltages possible (see Technical specifications). When higher operating voltages (e.g. 24 V) are used, little current flows through the RS-485 bus line and the voltage drop or associated problems are minimised.
In contrast to the first wiring variant, only one power supply unit is required at the beginning or end of the RS-485 bus.
Looping through at Vin and GND
With this variant, each router (SI.GN.CR) is supplied with the same power supply unit at the bus power supply connection (Vin and GND in). The connection cable therefore does not have to be routed to the external power supply connection on the side. However, only low operating voltages are possible (see Technical specifications). This results in a significantly higher current flow compared to the other wiring variants and problems can occur due to voltage drop with long cables (for recommended cable lengths, see Technical specifications).
In contrast to the first wiring variant, only one power supply unit is required at the beginning or end of the RS-485 bus.