IOX Modbus Software Setup (Release 3.3 and Prior)

Owned by Nina Cardillo (Unlicensed)
Last updated: 26-Oct-2022 by Nina Cardillo
3 min read

For SmartServer 3.4 and higher, see IOX Modbus Software Setup.

This section describes how to enable Modbus and setup the UART configuration at the IOX device using the SmartServer CMS, and consists of the following:

Enabling/Disabling IOX Modbus

IOX Modbus can be enabled or disabled from the SmartServer CMS Datapoint Browser widget.

Note: Only one Modbus driver can be enabled at a time. When enabling the IOX Modbus driver, make sure that the Modbus driver of all other SmartServer IOXs and Modbus drivers are disabled.

To disable the SmartServer Modbus driver, first go to the SmartServer’s Configuration UI→RS-485 tab. Then, on the RS-485 Configuration page, change the Bus type of both RS-485 1 and RS-485 2 to anything other than Modbus.

For more information about the RS-485 Configuration page, see (Optional) Add a Modbus RTU Interface, Setting the Modbus RTU Configuration.

The IOX device's modbus_active property controls the Modbus engine of IOX. Valid values for the modbus_active property are true or false.

To change the IOX Modbus modbus_active property, perform the following steps:

  1. Open the CMS Devices widget.



  2. Click the Action button () for your iox[1-n].sys device (where iox1.sys is the first installed IOX, iox2.sys is the second, etc.) and select the View Datapoints action.



    The Datapoint Browser widget appears for the selected IOX device.

    Notes: Click the Expand button (  ) for a better view of this widget. 



  3. Click the Action button () for the modbus_active datapoint and select the Edit Value action.



    The Edit Value view appears for Modbus control.



  4. Edit the Modbus control (i.e., true or false) as needed.

  5. Click SAVE to store the Modbus control setting.

Changes to the modbus_active property initiates a reboot of the IOX device. Rebooting and restoring device operations takes about 2 minutes to complete.

Setting the UART Configuration of IOX Modbus

If the Modbus driver of a particular IOX is enabled, then users can modify its UART configuration parameters from the SmartServer CMS Datapoint Browser widget by editing the value of the modbus_uart_cfg property.

Default UART parameters

The default UART parameters are 19200 baud rate, no parity and 2 stop bits.

To change the IOX Modbus modbus_uart_cfg property, perform the following steps:

  1. Open the CMS Devices widget.



  2. Click the Action button () for your iox[1-n].sys device (where iox1.sys is the first installed IOX, iox2.sys is the second, etc.) and select the View Datapoints action.



    The Datapoint Browser widget appears for the selected IOX device.

    Notes: Click the Expand button (  ) for a better view of this widget. 



  3. Click the Action button () for the modbus_uart_cfg datapoint and select the Edit Value action.



    The Edit Value view appears for the Modbus UART configurations.



  4. Edit the Modbus UART settings (i.e., baudrate, stopbit, parity) as needed.

  5. Click SAVE to store the Modbus UART configurations.

When edits are made to the modbus_uart_cfg property, SmartServer CMS publishes a message similar to the following:

glp/0/17q3knb/rq/dev/iap/1.sys/if/cfg/0 {"modbus_uart_cfg":{"value":{

  "parity": 0,

  "baudrate": 19200,

  "stopbits": 2

}}}

Changes to the modbus_uart_cfg property initiates a reboot of the IOX device. Rebooting and restoring device operations takes about 2 minutes to complete.