Controlling E9Screen EPC9 Installation 85
• AD-7 is the I-mon 1 input, i.e., the current input after filter 1.
To read V-mon, one has to connect the corresponding V-mon output of the EPC9 to any
suitable AD-input channel (but not 6 or 7). The user can now switch between two
programs. In this configuration, one can use the user program for data acquisition and
processing, while E9Screen is used to control the EPC9 settings, such as gain and
compensations. The holding potential is best set in E9Screen. If the holding potential
should be set from the user program, one has to control DA-3, which directly applies the
voltage to the EPC9 (scaling is 0.1, i.e., an input of 100 mV will translate to 10 mV).
Alternatively, voltages can be applied to the EPC9 by setting DA-0, DA-1, or DA-2, and
connecting that DAC to the external stimulus input of the EPC9. In this case, activate the
External Stimulus Input option in E9Screen, i.e., setting an appropriate external stimulus
scaling factor.
Controlling the EPC9 from another Program
Sending Commands to E9Screen
E9Screen can be controlled from another program by a simple “batch file control”
protocol. This “batch file control” protocol is simple, fast, and platform independent. The
new control protocol allows to control the EPC9 over a network, even one with different
platforms, such as Windows, Macintosh, Unix, OS/2, or workstations. Thus, it is now
possible to control the EPC9 from computers running a multitasking operating system
which can create and read shared files (e.g., Windows 95, Windows NT, MacOS, etc.).
Controlling E9Screen from another program is possible by communicating via two
ASCII-files. The user writes the commands to one file (the “command” file) and E9Screen
communicates back by writing to a second file (the “response” file). The user program
has write permission (plus sharing permission) on the “command” file it will write to.
E9Screen will access that file with read and shared permission only. The reverse is used
on the second file, the “response” file: E9Screen will have write and sharing permission,
and the user program read permission only (plus sharing permission, of course).
The first line in the “command” file must contain one positive number (as ASCII, e.g.,
“+1234”). This “command index” is interpreted by E9Screen as follows:
• If this number is zero or negative, E9Screen does not execute the commands in the
“command” file.
• If the number is larger than zero, E9Screen will execute the instructions
immediately. E9Screen will write that number to the “response” file to flag
execution once all commands have been executed.
• To prevent E9Screen to execute the instructions more than once, E9Screen will not
execute any further commands until the “command index” value is changed by the
user program.
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