PVA-3000 Reference Manual
December 2, 2019 Sifos Technologies
4. PowerShell PSA Software
PowerShell PSA is a script development and interactive command execution shell built upon the Tcl/Tk scripting
language (version 8.4.5 or later). Tcl/Tk is an open source, portable, and easily extendable programming language
developed for Unix (Linux) and subsequently extended to Windows and MAC operating systems. Compiled versions
of Tcl/Tk are available from the ActiveState Web-Site (www.activestate.com). Tcl/Tk as required for the PhyView
Analyzer will automatically be placed on Microsoft Windows computers when PVA software is initially installed.
Tcl (Tools Command Language) is a scripting language consisting entirely of commands for developing programs that
run on and utilize command line interfaces. Tk is a significant extension to Tcl to enable Graphical User Interface
(GUI) applications that are (for the most part) platform-independent.
4.1. TCL and Wish Shells
PowerShell PSA is provided with access to both a Tcl shell and a Wish shell. Shells are interactive command consoles
just like the traditional DOS command shell that accompanies Windows or a “terminal” shell in Linux. In fact, when a
Tcl or Wish shell is opened on a Windows-based system, traditional DOS commands such as “dir” are fully available.
Both Tcl and Wish shells support interpretive command execution, meaning commands may be typed and executed
immediately when the [Enter] key is pressed. There is no compilation or linking required for Tcl/Tk commands. This
feature makes Tcl/Tk an attractive solution for instrument control. Tcl is also quite powerful at managing and
analyzing arbitrary data structures through its “list processing” capabilities. There is a considerable body of
information regarding Tcl and Tk that is freely available over the Internet. Additionally there are some commonly
used reference books including “Practical Programming in Tcl and Tk” by Brent Welch. The remainder of this
manual will assume that the reader has some familiarity with Tcl – familiarity with the Tk extensions to Tcl is not
necessary.
The Tcl Shell (see Figure 4.1) is purely a command entry and program execution shell that does not support GUI
application development. It supports keyboard entry, mouse operations, and shell configuration in a manner consistent
with the host command shell (e.g. Windows “cmd” shell or Linux “terminal” shell). It supports interactive user
prompting (via “standard input”) from a script. The Tcl Shell will not support Tk graphical interface extensions.
The Wish Shell (see Figure 4.3) is a newer shell designed to enable GUI application development. PowerShell Wish
uses the top-level window created by the Wish Shell to present a “Close PowerShell” button since the console window
opened by Wish is subsidiary to the top-level window. As with the Tcl Shell, the Wish Shell may be used either for
script execution or interpretive command execution. PowerShell Wish must be used by any applications or command
sequences that produce PSD traces since these require the Tk resources available under Wish.
4.1.1. Tcl Versus Wish in the PC Windows Environment
On Microsoft Windows systems, when a Tcl Shell is opened, users may right-click on the title bar to set properties for
the console shell. Generally, PC users will benefit from configuring the shell properties to support “QuickEdit” and
“Insert” modes. Text may be copied using the mouse to select the text and pressing [Enter] on the keyboard. Text
may be pasted by using the mouse or cursor keys to position the cursor and then right-clicking the mouse. One handy
feature of the Tcl shell is ability to select and copy columns of text or data. A second benefit is that the screen buffer
length can also be configured to very large sizes as part of the console settings.
Wish is more “Windows-like” in that users may use typical methods of selecting, inserting, deleting, and copy-paste as
are used in other Windows applications. Also, Wish is Tcl and PowerShell command-knowledgeable and will color
code all known commands as they are typed into the shell. Wish supports Tk graphics and offers easy access to
graphical user interface commands and tools such as message boxes. PowerShell Wish enables the display of PVA-
3000 PSD traces using a single command from the shell. One limitation with the Wish Shell under Windows is that
any applications utilizing command-line prompts to the
user will not function properly since Wish is will not take
“standard input” from the command shell. Also, the
screen buffer length is limited and fixed.
4.2. PSA Connection Dialog
Unlike PVA Interactive, PowerShell PSA has the
capability to connect to any Sifos Technologies
PowerSync Analyzer (PSA) or PhyView Analyzer (PVA),
including instruments that may include both test blade
types. When PowerShell Tcl is opened (see Figure 4.1),
a command line prompt notifies the user of the default (or
last used) instrument address and offers an opportunity to
Figure 4.1 PowerShell TCL Connection Dialog
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