Specify Feed Data and Non-Printable Characters

This section describes how to specify feed data and non-printable characters in DNC-Max.

Feed data is the term used for any information sent or received by DNC-Max that is not part of the actual file being transmitted.

The following is an example from the standard protocol configuration, where the CNC requires a '%' character followed by a ASCII 0 to signal end of transmission.

Send at end of feed.

This also demonstrates how to specify non-printable characters, using the standard ASCII name "NUL" preceded by a "\".

You can also enter "\0" to specify ASCII 0. But notice that the next time you open the configuration dialog, this has been converted into "\NUL".

The ASCII names for all non-printable characters (ASCII 0 ASCII 31 and ASCII 127) are listed in ASCII Table.

If you need to specify a non-printable character followed by one or more regular ASCII characters, you must insert a space after the ASCII name. Ex. "\EOT stop", the space character will not be sent. To send a space after a ASCII name, you must enter two spaces.

Pay attention when you enter data in multi line input fields like Send data above. If you press enter, the cursor will move to the next line, and server will send the specified data, followed by a newline (see below for further information).

An alternative solution to specifying %\NUL is shown below, in this case only '%' is specified in the Send data field, and the ASCII 0 character is instead send using the Send character field.

Alternate solution to end of feed problem.

Specifying Multiple Lines

In all multi line input fields you can enter more than one line. The following is an example from the standard protocol configuration, where the CNC requires a line containing "M30", followed by a line containing "%".

Send multiple line at end of feed.

Notice that the cursor is at the beginning of the next line following the line containing "%". This happens if Enter was pressed at the end of the "%" line. After each line, the server will send the newline character(s) specified for the port. The result is shown in the terminal window below.

Result of sending feed data with linefeed.

If you do not want to send newline characters after the last line, make sure that you did not press enter, at the end of the last line.

To verify that no extra newlines have been entered, click with the mouse in the input field, below the last line you entered. If the cursor moves to the beginning of the next line, this indicates that you pressed Enter, if you do not want a newline character, press Backspace to delete it.

The result of sending the two lines, where no newline is sent at the end of the second line is shown in the terminal window below.

Result of sending feed data with no linefeed.

Specifying Enviroment Variables

You can also specify environment variables in feed data. The example below is from the standard protocol, and it demonstrates how to ensure that the correct feedrate, spindle speed and tool number is used when you restart transmission from any point.

Using environment variables in feed data

For further information about environment variables, please refer to the Reference Manual.