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Allen-Bradley ControlLogix Ethernet Driver Help


Descriptions of the parameters are as follows:


CL ENET Port Number: This parameter specifies the port number that the remote device is configured to use (such as 1756-ENBT). The default setting is 44818.


Request Size: This parameter specifies the number of bytes that may be requested from a device at one time. To refine the performance of this driver, configure the request size to one of the following settings: 32, 64, 128, or 232. The default setting is 232 bytes.


Perform Block Writes for Function Files Supporting Block Writes: Function files are structure- based files (much like PD and MG data files) and are unique to the MicroLogix 1100, 1200 and 1500. Supported function files include the following: High Speed Counter (HSC), Real-Time Clock (RTC), Channel 0 Communication Status File (CS0), Channel 1 Communication Status File (CS1), and I/O Module Status File (IOS). For more information, refer to "Block Writes" below.

For applicable function files, data can be written to the device in a single operation. By default, when data is written to a function file sub element (field within the function file structure), a write operation occurs immediately for that tag. For such files as the RTC file, whose sub elements include hour (HR), minute (MIN) and second (SEC), individual writes are not always acceptable. With such sub elements relying solely on time, values must be written in one operation to avoid time elapsing between sub elements writes. For this reason, there is the option to "block write" these sub elements. The default setting is unchecked.

Block Writes

Block writing involves writing to the device the values of every Read/Write sub element in the function file in a single write operation. It is not necessary to write to every sub element before performing a block write. Sub elements that are not affected (written to) will have their current value written back to them. For example, if the current (last read) date and time is 1/1/2001, 12:00.00, DOW = 3 and the hour is changed to 1 o'clock, then the values written to the device would be 1/1/2001, 1:00.00, DOW = 3. For more information, refer to the instructions below.

1. To start, locate the Function File Options tab in Device Properties. Then, select the Perform Block Writes for Function Files Supporting Block Writes checkbox to notify the driver to utilize block writes on function files that support block writes.

Note: Changes will take effect upon clicking OK or Apply.

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