WIN95 RS232 Low Speed

Hi
I have connected PC(166Mhz)Win95 and PLC FX2N Mitsubishi.
The program (written in VBasic 5) collects data frop PLC by reading it from RS232.
Baud Rate is 9600

The speed collecting data is slow. When the same program runs on Laptop 1,3Ghz WinXP then the speed of reading data from PLC
rises many times.
Is it problem in Win95 which has maybe old drivers for RS232?


Kelm

Perhaps the problem is the difference between "166Mhz" and "1,3Ghz". 9600 baud would be the same on both machines, but there is an lot of computing for a VB program.

Older computers had some limitation like RS232 maximum baud rate
of 38400 or 115200bps which is way higher than puny 9600.
Newer machines support RS232 speeds as high as 921600.
As already mentioned, it is likely that collected data is
transfered in fragments and faster PC handles associated overhead
(processing) much faster. What's stoping you from getting faster
machine? I've retired just about everything under 1GHz.
Used PC shops here sell PCs like PIII-700/128Mb/10Gig/CD/1.44/NIC etc
for ca $150-200 canadian.

"rest in pieces"

If the reason is in processor speed, then its ok. I was little worry about if the problem could be in program.
In my project this PC166 has only one goal- to tranfer data from PLC
to internet and it will stay working and lay under dust for long years
Because I choose so cheap solution.

Clock of Processor not influencied baud rate. Is running secondary chips

You problem drivers, specific function or bibliotec... or config

My system W95, run SW diverses for DEMOs from SCADA, drivers aquisition and comunication external equipament is good.

I find it config.
Execute ->sysedit

SYSTEM.INI

[386Enh]
COMxBuffer=1024 (Is set buffer in Bytes)

x=number the COM

dandrade said:

I find it config.
Execute ->sysedit

SYSTEM.INI

[386Enh]
COMxBuffer=1024 (Is set buffer in Bytes)

x=number the COM

Click to expand...

Since you stopped using the translator Dandrade, your english is better. :site:

The tip is good but I think he missunderstood what
is potential problem as discussed above. I have had
similar experience where original program was very slow.

Baud rate is set by different clock (dedicated one)
and it is not affected by CPU clock speed.

The thing is that this PC is not only receiving data
through RS232 (this is easy, even very first PCs could
do that without problem).

This PC is also evaluating data and acting as a webserver.
Depending on experience of the programmer and complexity
of of the task, this could be rather poor or very
very efficient program.

If the first case is what he's got, faster PC is definitelly
having easy time crunching data and processing inefficient
code which in turn results in faster overal performance.

In my case as mentioned above, modified logic nearly tripled
performance which was almost good enough on originally used
P75. But since this was very old machine and I don't like to
be called if something fails in the middle of the night,
I decided to put faster machine anyway.

Nothing like a piece of mind...

[

This PC is also evaluating data and acting as a webserver.
Depending on experience of the programmer and complexity
of of the task, this could be rather poor or very
very efficient program.

I dint make web server. In my project Remote computer has own visualised program that knows Local computer's IP adress. (Winsock to communicate between Local and Remote computers.)
Today I found, why my PC 166 handled too slowly RS232. Problem was in program architecture. I used timers for reading and writing bytes from com port. That was mistake.
I got to know that timers on PC166 VBasic environment are sensless already at interval <50(ms).

Now I removed these timers and communication speed is very good.