Chapter 7 - RUNNING THE LTP PROGRAM ON-LINE OVER THE NETWORK

In addition to running the LTP program solely on one computer, it is possible to utilize the Microsoft Workgroups Network to: 1) plot graphs on a printer attached to a remote computer on the network, 2) to save ADsweep and calculation files to a remote computer on the network, and 3) do on-line multitasking over the network - on other words, stimulate and acquire data with the LTP program on the data acquisition computer, and read and analyze the data files on-line with a custom program on the other remote networked computer.

To do this you must have either Microsoft Windows 3.x, Windows 95/98 installed on the remote computer and either Microsoft Windows 3.x or Windows 95/98 (or even Microsoft Workgroup Add-On for MS-DOS which operates the same as with Windows 3.x) installed on the data acquisition computer.

7.1 Plotting On-line to a Printer Attached to Another Networked Computer

Note: plotting over the network can be much slower than plotting directly through an LPT port directly connected to the data acquisition computer.

7.1.1 If you are running the LTP program on a computer having Windows 95 or Windows 98:

Share the printer on the remote computer you want to connect to. This computer can have either Windows 95/98 or Windows 3.x, it doesn’t matter.

In the data acquisition computer, first go to the MS-DOS mode, then go to any directory (say C:\ANYDIR) and type in the following command (although not the only possible command) to start the network, and log onto the \010704 directory of the remote computer (commands can be in upper or lower case):

C:\ANYDIR> net use lpt1: \\remotecomputername\printername ? /savepw:no

where ltp1: means the printer port LTP24 wants to plot to (chosen in the Printer Port Dialog Box, Fig. 2.10.1; ltp1: can also be lpt2: or lpt3:), \\remotecomputername\printername means log on to this remote computer and its shared printer, ? means get a prompt to enter password, and /savepw:no means that the password you type in any password list.

Then in the data acquisition computer start the LTP24 program as normal (either on C: drive or ‘on’ a networked drive as discussed in Section 7.2, and assuming a Labmaster board was being used):

C:\ANYDIR> ltp24 labmaster

Then (while running LTP24) print to the remote printer as if it were connected directly to the LPT1, LPT2 or LPT3 port. After you exit the LTP program, you can break the printer connection by using the following command:

C:\ANYDIR> net use lpt1: /delete /yes

where ltp1: again means the printer port LTP24 wants to plot to (and can also be ltp2: or lpt3:), /delete means break the printer connection, and /yes means to carry out the action without further prompting.

For getting more information before proceeding, type the following command

C:\ANYDIR> net use /? more

7.1.2 If you are running the LTP program on a computer having Windows 3.x:

Share the printer on the remote computer you want to connect to. This computer can have either Windows 95/98 or Windows 3.x, it doesn’t matter.

You can start an easy to use pop-up program to establish network connection to the printer by typing:

C:\ANYDIR> net

Just follow the directions.

Alternatively you can type in the same commands used by computers having Windows 95/98 (see Section 7.1.1). In other words you can type:

7.2 Save Data Files On-line to Another Networked Computer

7.2.1 If you are running the LTP program on a computer having Windows 95 or Windows 98:

Make sure the remote computer to receive data is logged onto the network and that the directory that is to receive data is shared in Full, Read/Write mode (otherwise LTP24 will exit!). This computer can have either Windows 95/98 or Windows 3.x, it doesn’t matter.

In the data acquisition computer, first go to the MS-DOS mode, then go to any directory (say C:\ANYDIR) and type in the following command (although not the only possible command) to start the network, and log onto the \010704 directory of the remote computer:

C:\ANYDIR> net use * \\remotecomputername\010704 ? /savepw:no

where * means choose the first available drive for representing the remote computer and its shared data directory, \\remotecomputername\010704 means log on to this remote computer and its shared data directory, ? means get a prompt to enter password, and /savepw:no means that the password you type in any password list.

Then in the data acquisition computer go to the first drive available (say it is the E: drive), start the LTP program (lets also say using for example a labmaster board):

When you start the LTP in the E:\ directory, all the ADsweep files (*.P0, *.P1, *.AP0, *.AP1), all amplitude/calculation files (*.AMP), and any LaserJet plot files (*.LJ?) will be saved in the remote computer.

After you exit the LTP program, you can break the network connection by using the following command (after first going to the C: drive):

where * again means just used drive representing remote computer and its shared data directory, /delete means break the network connection, and /yes means to carry out the action without further prompting.

For getting more information before proceeding, type the following command

C:\ANYDIR> net use /? more

Note that even though you are logged onto the drive e: directory on the remote computer, the LTP24.EXE program still runs on the data acquisition computer, because the directory containing the LTP program (\LTP24) is in the path statement in the data acquisition computer’s autoexec.bat.

It is possible to log onto the remote computer, run LTP24, exit LTP24, and then log off the remote computer using a batch file but in between logging onto the remote computer and going to the network drive, you probably will have to put in a pause statement to allow the remote computer to respond before moving to it, in other words:

7.2.2 If you are running the LTP program on a computer having Windows 3.x:

Make sure the remote computer to receive data is logged onto the network and that the directory that is to receive data is shared in Full, Read/Write mode (otherwise LTP24 will exit). This computer can have either Windows 95/98 or Windows 3.x, it doesn’t matter.

In the data acquisition computer, first go to ‘real’ MS-DOS (not the DOS compatibility box), then go to any directory (say C:\ANYDIR).

For computers using Windows 3.x use can start an easy to use pop-up program to establish network connections by typing:

C:\ANYDIR> net

Just follow the directions.

Alternatively you can type in the same commands as used by computers with Windows 95/98 (see Section 7.2.1). In other words, type:

Note that even though you are logged onto the drive e: directory on the remote computer, the LTP24.EXE program still runs on the data acquisition computer, because the directory containing the LTP program (\LTP24) is in the path statement in the data acquisition computer’s autoexec.bat.

It is possible for a computer having Windows 3.x to log onto the remote computer, run LTP24, exit LTP24, and then log off the remote computer using a batch file in the same manner as with a computer having Windows 95/98 (see Section 7.2.1).

7.2.3 Advantages of networking

First, using this technique will allow you to save data directly onto your analysis computer; this is particularly good if space is limited on your data acquisition computer.

Second, you can reanalyze your data on the remote computer using the LTP program at the same time as the LTP program on the data acquisition computer is doing on-line analysis. To do this - on the remote computer enter the DOS compatibility box for either Windows 95/98 or 3.x (NOT the MS-DOS Mode or ‘real’ MS-DOS as this will break the network connection!). Then go to the directory where the ADsweep and calculation files are being loaded into. Then start the LTP24 program and reanalyze the files in the normal manner. There will be no conflict because the data acquisition computer is only writing files to the directory and the remote computer is only reading (the already completely written) files.

7.3 Do On-line Acquisition and Analysis on Two Separate Networked Computers

The real advantage of saving your data on a remote networked computer is that it allows you to stimulate and acquire data on the data acquisition computer using the LTP program, and analyze on-line the data files in the remote computer using a custom program. There is no way I can program all the on-line analyses you might want to do. The custom analysis program has to check if a new ADsweep file has been written to the shared directory, and if so, load the ASCII ADsweep file and analyze it. This custom program can be written in any language such as Visual Basic, Delphi, Excel script language, Origin script language, or C.

In essence this functionally is multitasking. Because DOS is not a multitasking operating system, the LTP program cannot operate with another program running simultaneously on the same computer. However, two programs running simultaneously on two networked computers (1 program per CPU) with both programs accessing the same data files in one shared directory is functionally almost identical to two programs running simultaneously on one multitasking computer (two programs sharing one CPU) with both programs accessing the same data files in one shared directory.

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