frame?

[richerdick]

Can anyone give me a brief idea of what the term frame refers to concerning PLC programming.
I believe it has something to to with the configuring of comms ports to communicate with external devices but want to know more

 

[Watthour]

I've only been doing this since about 1983, so I'm rather new at it, but I've never encountered the term "frame" relating to lader logic programming of PLCs. The old AB Industrial Terminals and "micro" cassette recorders for PLC 2/15s, 2/20s, and PLC3s had a massive "frame" but that's an entirely different mater, I'm sure.

Siemens PLCs used "blocks" for programming, and some of the older Gould/Modicons (through the Micro 84s) had "cards" for programming, but "Frame" is not in my PLC vocabulary.

But, as I stated, I'm fairly new at this, so I'm all ears.

 

[richerdick]

This type of PlC is manufactured by Harland simon, the code is similar to ladder logic but tends to function on a lower level. I have been doing some poking abut and it has become apparent that it is something to do with preparing a block of data to be sent over a comms port

 

[jde777]

Are you thinking of serial character framing? For comms through a serial port of a plc?

 

[itsmoked]

Now THAT would make some sense. Nice idea jde777.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[danw2]

The term 'frame' appears 70+ times in the Modbus protocol specification "MODBUS over Serial Line Specification and Implementation Guide V1.02" at

http://www.modbus.org/docs/Modbus_over_serial_line_V1_02.pdf

example:

Dan

 

[jde777]

http://cnx.org/content/m12293/latest/

some insight

 

[richerdick]

thanks i think that adds up now