Documentation - RS-485 network

RS-485 network

ViS-A controllers has RS-485 bus for connecting devices that can operate using the Modbus protocol in the baudrate range from 9600 to 115200 bps.
All signals are galvanically isolated from the main controller circuit (high speed digital isolators are used).
With RS-485 network possible to increase the total number of inputs/outputs up to 240 (plus inputs/outputs on the CNC controller board).

Both devices produced by ViS company (ViS-IN8, ViS-OUT8) and devices from third-party manufacturers (for example, spindle motor inverters) can be used as devices operating as part of the RS-485 network.

The maximum length of a twisted pair cable with a characteristic impedance of 120 Ohms is 300 meters.
The maximum number of devices in the RS-485 network is 30.

For an RS-485 network, you must use a twisted pair cable with a characteristic impedance of 120 Ohms. The use of any other cable, including coaxial, can lead to unstable data transmission and low noise immunity of the line.
It is also recommended to use shielded twisted pair cable, especially in harsh interference environments.

Baudrate

The baudrate of the RS-485 network is set by parameter 7010.
Devices manufactured by ViS company determine the baudrate automatically.

Address programming

To connect devices manufactured by ViS company you need to program the device address.
The device address is programmed by the ViS controller as follows:

Connect only one RS-485 device to the ViS controller for which you want to program a new address
Open the PARAMETERS panel
Open parameter 7100 - Programming a new device address
Enter an address in the range from 1 to 30 and click OK

Connecting devices

Devices manufactured by ViS company connect to the RS-485 network automatically based on the programmed address.
Third-party RS-485 devices must be added manually. For this purpose parameters 7000 and 7001 are used.

The RS-485 network configuration can be changed by opening parameter 7000:

Here you can add any device designed to work via the Modbus protocol, for example, a spindle inverter.
Also in this panel you can enable or disable any device on the RS-485 network using the checkbox in the column called "POLL".
ViS devices can be rebooted using the RESTART button.

You can add a third-party device to the RS-485 network that supports operation via the Modbus protocol by opening parameter 7001:

In order for the device to function correctly as part of the ViS CNC system, it is necessary to correctly describe its operation using the Modbus protocol. For this open the settings from the far right column "MODBUS RTU", the following window will appear:

Here, each function is indicated with a command and its corresponding code so that the ViS CNC controller can recognize it.
Data on commands and their corresponding codes can be found in the operating instructions for the device.