3M M2256PW User Manual - Page 31

3M™ Display M2256PW User Guide 31 The header is the first character in the command string and is the ASCII start-of-header control character SOH. The hexadecimal code for the ASCII SOH control character is 01. To start the command sequence, use the key combination Ctrl A (^A). If you are working with an IBM PC compatible system, the Ctrl A key combination immediately returns an ASCII ☺ character. The command, which always follows the header, consists of ASCII uppercase letters and numbers only (printable characters). The terminator is the last character of each command string and is an ASCII carriage return CR. An ASCII CR control character is 0D hexadecimal. To enter a carriage return, ending the command sequence, use Enter or the key combination Ctrl M (^M). This appendix lists each command as a string of ASCII control characters and printable characters consisting of a header, the command, and a terminator as follows: Command Receiving Responses from the Controller After executing a command, the controller returns a response or acknowledgment to the host system. Each controller response consists of a header, the command response, and a terminator in the following format: Command Response Note: The following descriptions of header, response, and terminator, use 3M Touch Systems terminal emulator key sequences. The format of controller responses varies depending on the terminal emulation mode you are using. The header is the first character in the response string and is the ASCII start-of-header control character SOH. The hexadecimal code for the ASCII SOH control character is 01. If you are working with an IBM PC compatible system in terminal mode, the SOH control character returns a ☺ character to the sensor. The command response, which always follows the header, is a range of ASCII characters depending on the type of command sent. Responses can be in many forms. For example, one standard response is 0 (ASCII character 'zero' or 30 hexadecimal). This response indicates a successful command completion for most commands, while it indicates a failed completion for other commands. Refer to the firmware reference section for a description of what the response indicates for each particular command. Another standard response is 1 (ASCII character 'one' or 31 hexadecimal). In most cases, this response indicates the command failed. The controller received an invalid command that it could not execute. Some possible reasons for a command failure include: • The command was not formatted correctly. • The system parameters were not set up to allow command execution. • The controller does not support the command. 3M Touch Systems, Inc. Proprietary Information