Controlling E9Screen EPC9 Installation 86
• Every command plus the required parameters must be in one text line, i.e.,
terminated by a “CR” character code (any following linefeed character will be
ignored).
• E9Screen writes the responses to the “response” file. In the first line of that file,
E9Screen writes the “command index”. The following lines will contain the
responses, if any, one response per line.
• The name of the “command” file must be “E9Batch.In”, the one of the “response”
file “E9Batch.Out”. Both files will be inside the default folder of E9Screen, usually
the folder “E9Screen”.
Thus, communication would proceed as follows:
➊ The user program is started first:
It has to create a file in the “E9Screen” folder named “E9Batch.In”. It has to keep
this file open with “write” and “shared” access permission.
➋ Then E9Screen is started:
Enable the “Enable Batch Control” option. E9Screen will open the file
“E9Batch.In” with “read” and “shared” access permission. Also, E9Screen will
now create the "E9Batch.Out" file with “write” and “shared” access permission.
➌ Now, E9Screen will immediately execute the commands in the command file,
provided that the “command index” is larger than zero. E9Screen writes the
“command index” and eventually any error and requested answer to the
“response” file.
➍ Next, the user switches back to the user program.
➎ Any time the user program writes to the “command” file, E9Screen will scan the
command file and execute the commands, if the “command index” changed.
Windows 95 and Windows NT: On computers running Windows 95 or Windows
NT, E9Screen will immediately execute the commands.
Macintosh: On computers running MacOS, E9Screen will immediately execute
the commands, if it is the front application. If E9Screen is not the front
application, then E9Screen will get active when the front application calls the
“Toolbox” routine “GetNextEvent” or “WaitNextEvent”.
➏ The user program can now read the “response” file. The first line should mirror
the “command index”. Subsequent text lines may contain responses and error
messages (see list below). There are the following possibilities:
- There is no further line in the response file. This means, that no error occurred
during execution and that no response was requested.
- There is additional text in the file. The user can easily recognize error
messages, because the first character in an error message is a lower case letter.
All other responses start with an upper case letter.
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