Sending ASCII data in Hex format?

Can someone help me to find instruction which stores ASCII characters to String data type tag and Is it possible to convert an ASCII string to Hex (hexadecimal) format?

My printer accepts ASCII characters in Hex format. I have a gateway from RTA which takes data in String tag and transfers it to printer which accepts ascii data using TCP/IP.
I am using Control Logix PLC.

You are mixing concepts in your question.

ASCII is a defined code for text (visible characters) and format control characters (like linefeed and carriage return).

Hex(adecimal) is a method for displaying the contents of a binary word by showing a code for each group of 4 bits. The codes are the characters 0-9 and a-f.

Can you provide a link to the manual for your printer and also point out where it defines 'characters in Hex format'?

in there hexadecimal form, this is for the ease of presentation for the writing of the documentation

Click to expand...

So you see, they are showing the hexadecimal form for clarity. It does not affect the sending. The ASCII will be sent in their standard form. Now, the 'ESI' protocol sounds like a data protocol (which command codes are used and how they are interpreted by the printer) as opposed to a transmission protocol (how the transfer of information is handled on the Ethernet cable). I have no information on whether TCP/IP transmission is supporter by ControlLogix.

Here is an interface unit which may help.

Thank you for your reply. I already bought that RTA unit which sends ascii data from Control Logix to TCP/IP device. You are correct, ESI is data protocol. I have all these commands in hexadecimal form. Was not sure how to convert it into ascii and send it through PLC.

The control codes ARE ASCII characters. The upper hex character is either 0 or 1.

Assuming you are using a string tag in the ControlLogix PLC simply fill one with the required control characters (using the RSLogix5000 tag monitor/editor) ending in the 0D (Carriage Return) control characters. Set the string length to the number of control characters including the terminating CR. (Edit - actualoly the editor will properly set the length for you.)

You should set these up in seperate strings from the one used for communication to the RTA device then use the COP command to copy them into that communication string when they are needed.

The RTA device will see the non-zero length, copy out the characters and send them to the printer. It will also zero the string length. This is the clue for your PLC code to place another string (using COPy) into the communication string.

We have used Ethernet <-> RS485 Gateways from RTA. The 'String Length' method of handshaking (both directions) makes the PLC code incredibly easy.