Control Network Newsletter

BASrouterLX Advanced Slave Proxy Feature Benefits Users

November 2013 - The BACnet MS/TP standard allows for two types of devices - master and slave. A master device is one that participates in the token-passing process while a slave does not. The major difference between master and slave devices is slave devices do not support the BACnet discovery process. Only MS/TP master devices are discoverable. However, BACnet defines a slave proxy feature where a BACnet router can answer discovery requests on behalf of any connected slaves. The BASrouterLX supports slave proxy in both automatic and manual modes.

MS/TP slave devices are accessible using either Manual Slave Address Binding or Automatic Slave Discovery. MS/TP slaves can be addressed throughout the complete MS/TP address range.  A standard web browser is all that is needed to access the features of the high-performance router.

There are various Slave Proxy parameters including:

• Slave Proxy Enabled - When enabled, the router will proxy MS/TP slave devices for clients. Slaves can be discovered (when Auto Slave is enabled) and you can also manually enter information about the slaves. When Auto Slave is disabled, MS/TP slaves must be manually configured.
• Auto Slave Enable (Default Value Off) - When enabled, MS/TP slaves will be automatically discovered - if Slave Proxy has first been enabled.
• Auto Slave Table - This table lists the slaves that have been automatically discovered. To view the table, click View Auto Slave.
• Manual Slave Proxy Entry - Enter the MAC address, Device Instance, Vendor ID and MAX APDU for each slave device and then click Apply.
• Manual Slave Table - This table lists the Slaves that have been manually entered.

Enabling the Slave Proxy logging feature allows viewing of logging information for the BASrouterLX's communication with slave devices from its webpage. When auto-slave is enabled you can view the BASrouterLX attempts at communicating with slave devices on the network and any issues during the discovery process. You can also view any communication issues with manually entered slaves.

The BASrouterLX is part of the BASautomation family of BACnet devices. For more information, visit the BASrouterLX product page.