Visual Basic GEM Equipment Application

NAME

Visual Basic GEM Equipment Application

SYNOPSIS

GemEquip.exe

DESCRIPTION

Hume Integration provides Visual Basic source code and project files to create a GEM Equipment simulator application as part of its Application Development Package. This VB application software is a prototype or demonstration of the techniques that are used to combine the Hume GEM software which is based on Tcl/Tk, with User Interface and Equipment control logic that executes in a separate process or in separate processes. The VB application software is intended for Visual Basic version 6 on the Windows XP, 2000, or NT operating systems. The techniques used in this example could also be used from C++, Java, or a programming environment on a non-Windows platform.

When the VB application is executed, it starts a dmh_wish process running in the background. The dmh_wish process acts as the server of a DMH message group, and it also executes SECS/GEM equipment logic. The VB application uses DMH messages to control and integrate with the dmh_wish process. When the VB application is terminating, it also terminates the background dmh_wish process. If the VB application is terminated abruptly, the dmh_wish process terminates when it sees that the DMH communication is broken. The casual user is not aware that the apparent functionality is provided by the coordinated teamwork of the two applications, since he is never involved in the startup, shutdown, or cleanup of the background process.

INSTALLATION

The VB Application is distributed in a separate .zip archive file, VB_Equip.zip. If you received the DMH software on CDROM, the VB_Equip.zip archive is found in the subdirectory LAN_IMAGE. You will also need to install the DMH.ocx Active-X control from the archive file DMHocx.zip which is found in the same directory. (See DMHocx installation.) The distribution archive needs to be unzipped into a path of your choosing; for example, c:\hume. The archive includes the subdirectory VB_Equip. All of the source and project files are found in this subdirectory. The source files include:
DlgAlarmEdit.frm
A VB form for editing alarm definitions.
EquipUI.frm
The main form together with the application logic.
GemEquip.exe
A compiled executeable. VB6 runtime components need to be installed to use this.
GemEquip.vbp
The Visual Basic project file. This is the file to open in the Visual Basic Studio.
EquipUI.frx
Data that is used by VB to create and initialize the EquipUI form.

USAGE

The target audience of this software is a VB developer. The expectation is that the developer will load the software into the Visual Studio environment and examine the well-commented source code. The User Interface provided by the VB application is nearly identical to that provided by the gemsim Tcl application. However, a key difference is a set of buttons that will bring up diagnostic and development windows connected to the dmh_wish process.

To develop a GEM interface for real equipment, the developer should copy or mimic the logic found in the main form into his own application. The diagnostic and debugging capabilities can be made accessible behind a password protected system menu. As an alternative, it is possible to run separate utility programs when diagnostics are desired. With the background process performing as a DMH server, it is possible to connect to the process from anywhere in the network.

SEE ALSO

GEM EI Applications
The VB application uses the gemsim application that is usually installed in /usr/local/gem/equip/, and described in this document.
gemsim_server.bat
This batch file starts dmh_wish running as a background SECS process for use by external software. The dmh_wish startup imbedded in the VB application is nearly equivalent. The batch file contains documentation on the use of the DMH message system by the SECS/GEM logic.
secsport, hsms Tcl commands
The applications leverage the secsport and hsms commands that have been added to the extended Tcl interpreter.
Tcl SECS notation
The software manipulates SECS data structures using Tcl SECS notation.
DMH.ocx Active-X Control
The VB application uses an instance of the DMH.ocx Active-X control to integrate with the DMH message system using native VB events, method calls, and properties.
Distributed Message Hub (DMH)
This is the reference information on the DMH message system and its native Tcl API.

AUTHOR

Hume Integration Software.
This is licensed and supported software, (C)Copyright 2000 All Rights Reserved.

KEYWORDS

GEM SECS VB Equipment DMH Hume