DHRIO_CLX object

The DHRIO_CLX object represents the physical Allen-Bradley ControlLogix DH+/RIO Communication Interface module.

• 1756-DHRIO

This object is hosted by BACKPLANE_CLX.

Add the DHRIO_CLX object to your ABCIP hierarchy

1. Select and right-click on the New_BACKPLANE_CLX_000 object.

2. Select Add DHRIO_CLX Connection from the shortcut menu. The New_DHRIO_CLX_000 object is created.

3. Rename the newly created object as appropriate. The DHRIO_CLX Parameters configuration view is displayed.

This configuration view has three parameters, two of which are configurable:

• Module Type: (not configurable) Information provided automatically by the OI Server Manager (DH+/RIO Communication).

• Slot Number: A sequential number beginning with 0 (zero) assigned to each slot in a ControlLogix DH+/RIO Bridge module.

  • The slot number indicates where the sub-module resides.

  • The valid range is 0 - 16.

  • The default value is 0 (zero).

• Max CIP Connections per Channel: The maximum number of CIP connections that can be originated from the Communication Driver to the PLC. The number of CIP connections should be configured based on the load of messages that are sent to the device, and the hardware capabilities of the PLC processor. When multiple CIP connections are configured, the ABCIP Communication Driver distributes the number of messages across these connections to enable faster processing of the messages. For example:

  • If Max CIP Connections is configured as 1, then all messages will be polled through the single CIP Connection, one message at a time.

  • If Max CIP Connections is configured as 4 and there are 10 messages in the queue, then these 10 messages will be polled through 4 CIP Connections. 4 messages will be sent to PLC immediately, and the other 6 messages will be in queue. The next 4 messages will be sent to PLC after the first 4 messages are processed. The process will continue until all messages in the queue are processed.

  • The valid range is 1 - 31.

  • The default value is 4 (four).

    Note: For each CIP connection established, the PLC allocates certain resources to handle the connection. If too many CIP connections are established by the Communication Driver, the PLC processor allocates more resources for the CIP, which might affect the performance of other operations. For example, with 31 connections, the data updates become extremely sluggish since the PLC ran out of resources to handle the runtime logic and updating the control items. This is why it is important to configure the number of CIP Connections based on the hardware capabilities of the PLC processor.