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Microcontroller Based PLC Designing

Hi ,
I want to design a PLC which use two 8051 Microcontroller in
place of Microprocesser in which one operate as a execution unit and
second as a control
unit.Any body have an idea how to interface them.
 
Hi ,
I want to design a PLC which use two 8051 Microcontroller in
place of Microprocesser in which one operate as a execution unit and
second as a control
unit.Any body have an idea how to interface them.

What ever for? There probably is a more pointless exercise, but it
escapes me for the moment.
 
R

Rene Tschaggelar

Jan 1, 1970
0
Hi ,
I want to design a PLC which use two 8051 Microcontroller in
place of Microprocesser in which one operate as a execution unit and
second as a control
unit.Any body have an idea how to interface them.

You're about 20 years late. I can buy a PLC with
everything for 120$

Rene
 
S

Spehro Pefhany

Jan 1, 1970
0
What ever for? There probably is a more pointless exercise, but it
escapes me for the moment.

What don't you like about it? The other option would be to try to use
a pre-emptive scheduler to keep the PLC part consistent timing, since
high-quality control algorithms run on most 8051s will be much slower
than can be tolerated in the PLC loop. I've done the latter on
Freescale microcontrollers and it's messy too. As far as interfacing--
it's pretty situation-dependent. Maybe he could use SPI or I2C or
whatever with some simple protocol to allow the chips to talk to one
another. Or even just dedicate a port and some handshaking lines.

Best regards,
Spehro Pefhany
 
R

Rene Tschaggelar

Jan 1, 1970
0
Yes you are right . I am 20 year late but I am not going to run any
factory with ... I just want to learn .

Only if you cycle time is very short, then
splitting the communication from the control
loop makes sense. However, the communication
between the controller has to be very
efficient and short.

I'd set this cycle time below 1ms, where a
split of the solution in two controllers is
appropriate.

The 8032 family is outdated, kept for legacy
reasons to use the already existing tools.
Rather have a look at the newer families
such as PIC and AVR in the 8 bit world.

Rene
 
S

Spehro Pefhany

Jan 1, 1970
0
The 8032 family is outdated, kept for legacy
reasons to use the already existing tools.
Rather have a look at the newer families
such as PIC and AVR in the 8 bit world.

Rene

He mentioned the 8051. There are 8051s that run at 100MIPS.

Best regards,
Spehro Pefhany
 
R

Rene Tschaggelar

Jan 1, 1970
0
Spehro said:
He mentioned the 8051. There are 8051s that run at 100MIPS.

That still is the same family. With one
index (far-) pointer. And most are clock
div 12. Yawn.

Rene
 
I

Ian Bell

Jan 1, 1970
0
Rene said:
Spehro Pefhany wrote:

That still is the same family. With one
index (far-) pointer. And most are clock
div 12. Yawn.

Today most are NOT clock div 12.

IAn
 
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