Allen-Bradley ControlLogix Ethernet Driver Help
Descriptions of the parameters are as follows:
TCP/IP Port: This parameter specifies the TCP/IP port number that the device is configured to use. The default setting is 44818.
Connection Size: This parameter specifies the number of bytes available on the CIP connection for data requests and responses. The valid range is 500 to 4000 bytes. The default setting is 500 bytes.
Note: Only the ControlLogix 5500 and CompactLogix 5300 device models support this feature. In order to support connection sizes greater than 500 bytes, the device must support Firmware version 20 or later controllers and Ethernet bridge EN3x, EN2x, or EN5.x. Older Ethernet modules like ENBT and ENET do not support this feature. Devices that do not meet the necessary requirements will automatically fallback to the default setting of 500 bytes, although the requested size will be re-attempted after communications failure.
Important: The Connection Size value may also be requested through the System Tag "_ CIPConnectionSizeRequested." For more information, refer to Internal Tags.
Inactivity Watchdog: This parameter specifies the amount of time a connection can remain idle (without Read/Write transactions) before being closed by the controller. In general, the larger the watchdog value, the more time it will take for connection resources to be released by the controller and vice versa. The default setting is 32 seconds.
Note: If the Event Log error "CIP Connection timed-out while uploading project information" occurs frequently, increase the Inactivity Watchdog value. Otherwise, an Inactivity Watchdog value of 32 seconds is preferred.
Array Block Size: This parameter specifies the maximum number of array elements to read in a single transaction. The value is adjustable and ranges from 30 to 3840 elements. The default setting is 120 elements.
Note: For Boolean arrays, a single element is considered a 32-element bit array. Thus, setting the block size to 30 elements translates to 960 bit elements, whereas 3840 elements translate to 122880 bit elements.