Configure Daisy Chain (If Required by Application)

Daisy Chain is useful in applications where:

 

 

A Daisy Chain consists of one parent and one or more child devices. The child devices report their data to the parent, which then reports the data to the network, effectively allowing all readers to act as one. In other words, the outside world interacts with one unit – the parent reader.

 

The Device Discovery Utility (DDU) is used to configure the Daisy Chain group where the parent reader and the child readers are defined. The parent reader interacts with a host computer or PLC. A parent reader that receives a trigger will send a trigger to each of the child readers. Any symbol decoded by the child readers will be communicated to the parent, which collects all of the decodes from the children and will communicate them to the host. The Daisy Chain uses one UDP packet for the decoded data from all readers. Combined data from all readers larger than 3800 bytes will not be reported.

 

Overview of Setup Process

Use the Device Discovery Utility to define the Daisy Chain group, the parent reader, and the child readers.

 

Use WebLink to configure each of the readers in the Daisy Chain group as desired for the application.

 

Tips

The parent reader should:

 

 

The child readers should:

 

 

Parent and child readers should:

 

 

Setting Up a Daisy Chain Configuration with the Device Discovery Utility (DDU)

If your application requires readers to be deployed in a Daisy Chain configuration, the DDU can help you create such a configuration.

 

A Daisy Chain is a grouping of 2 to 8 readers that function as one. The DDU interface allows you to manage Daisy Chains, including their creation, monitoring, and deletion.

 

Connect 2 to 8 V430-F readers that have Daisy Chain-compatible firmware. From the DDU home page, click on the group icon located near the top-right.

 

 

On the Groups page, assign a Group Name and click Create. This opens the interface that allows you to create a new Daisy Chain.

 

Important: Only Daisy Chain-enabled readers will appear in this view.  

 

 

The five most important areas in the Daisy Chain creation interface are:

 

 

 

 

 

 

 

 

 

 

Note: The Create function does not delete a Daisy Chain and only resets the interface.

 

 

 

Below these buttons, messages will appear that indicate any errors in the potential Daisy Chain being created. These errors appear and disappear based on dynamic validation of user input.

 

 

The Daisy Chain creation interface is drag-and-drop, meaning you can move devices around the page to build your Daisy Chain.

 

The All Devices, Parent, and Children containers are drop zones for readers. To move a device, place the cursor over a device, left-click, and hold down. Then drag the device in another drop zone by moving the cursor / reader over it and releasing your mouse's left-click button. Valid reader drop zone areas are designated by the dotted grey line surrounding them.

 

Drag and drop a reader into the Parent drop zone. Drag and drop one or more other Daisy-Chain-enabled V430-Fs into the Children drop zone. Assign a name to the group.

 

If errors occur (A group name must be assigned or Group must consist of at least one parent and one child), resolve them as needed, and then you will see that the Create button will be active. A valid Daisy Chain configuration should resemble the example below.

 

 

If the Daisy Chain was created successfully, the popup will close, and the newly established Daisy Chain will be displayed as a diagram or map. This diagram is generated based on the number of devices in the Daisy Chain. Whichever number of devices in the Daisy Chain, the Parent always appears above and all Children devices below.

 

 

There is no limit on the number of Daisy Chains that can be created. All current, active Daisy Chains will appear on the Daisy Chain page in the DDU. Click on any Daisy Chain to open its information popup. This popup contains information about the Daisy Chain configuration, including Group Information, Parent reader identity, and Children reader identities. The Daisy Chain information popup also contains a Delete button, which deletes the entire Daisy Chain configuration – Parent and Children.

 

 

Daisy Chain Fundamentals

Parent: The master device in the group. Responsible for establishing the group on the firmware side and reporting the Daisy Chain to the DDU. There can be only one Parent in a Daisy Chain. The parent is responsible for receiving create and delete commands from the DDU.

 

Children: Any reader that is currently a part of a Daisy Chain that is not the Parent device is a Child device. Child readers report data to the Parent reader.

 

A Valid Daisy Chain:

 

 

 

 

 

 

The creation and deletion of Daisy Chains occurs via UDP messages that are sent from the DDU user interface to the readers. If a parent device recognizes that it has been configured in a Daisy Chain, it creates the firmware connection, and then broadcasts UDP messages that contain all the information needed by the user interface to produce a functional Daisy Chain configuration. The user interface will only create a new Daisy Chain if it receives a broadcast from the Parent device with the Daisy Chain information. The core communication between the user interface and the devices is via the Parent device. The firmware is responsible for connecting the Parent device to the Children devices and then reporting the status.

 

A Daisy Chain consists of one Parent and one or more Children devices. The Children devices report their data to the Parent, which then reports the data to the network, effectively allowing all readers to act as one.

 

Error Handling

If the Parent reader in a Daisy Chain is turned off for more than one minute, a Disconnected notice will appear in the dialog. This notice will disappear once the Parent reader is turned back on.

 

If a Child reader in a Daisy Chain is turned off, even temporarily, an Offline notice will appear below the respective Child on the reader map. Once turned back on, the Offline notice will disappear.

Some errors can occur when you have already established a Daisy Chain and confirmed that it’s working.

 

In this hypothetical error scenario, the Parent reader = P, the first Child reader = C1, the second Child reader = C2, and the third Child reader = C3.

 

The user shuts down the application and completely turns off power on P, C1, C2, and C3. The user comes in the following day and turns on all the devices except C3 and then starts the application.

 

The complete Daisy Chain can’t be re-initiated because it is missing a unit. To account for this, the application will place a “dummy device” in place of the missing C3. The dummy device will display an error icon, the missing device's MAC address, and an Offline status message. It will continue show this status if the browser is restarted. This offline device can’t be clicked in the Daisy Chain info page. It is only there to alert the user of the missing device.

If the user turns on C3 when seeing the status shown in the diagram above, the application will automatically resolve the issue and a new, fully-formed Daisy Chain with C3 as a full device will be created. There is no need to restart the browser or Parent device.