Serial Communication into Micro850

tim_callinan · Apr 14, 2014

Hello All,
I'm basically trying to get barcode numbers into my Micro850. I have the barcode working, plugged it into a computer and can view it on Hyperterminal. Next stage is getting it into the PLC. I've included a photo of our Micro850s. I think (and hope) there are two ways to get serial communication into the PLC. The first way is through the serial cable shown and the second would be getting a plug-in serial module which we dont have. My plan is to connect the barcode to the serial cable shown and hopefully access the data through connected components workbench. Is this possible or does anyone have any experience with this? Thanks for any assistance.
Tim

Lemming · Apr 15, 2014

The serial port (either onboard or pluggin) can be put into ASCII mode. I'd go for the pluggin module as they are cheap and easy to hookup...

To see the data you will need to setup a routine to scan the buffer, and read in on detection of a complete barcode. Not sure without more info what is needed to test that, but character count is probably a likely method...

mmmlinux · Apr 29, 2014

Alright, so ive been working with Tim on this project. I have the plc receiving the information and acting accordingly, but we were wondering if what ive done is the way that you would normally process ascii serial data, or if there is a better/ more efficient way. please see the linked ladder logic. http://imgur.com/Z3Rl2GQ

Lemming · Apr 30, 2014

I might have used an actual buffer count as a trigger for the read, and used the ARL instruction if you have a known delimitation character in lieu of a delay, but if it works ....

You ask 5 guys, and you'll get 5 variations...

mmmlinux · Apr 30, 2014

while i was testing i was just scanning what ever bar codes were near me, so they weren't always the same length. that's why i was using the delay + >0 combination more then anything. we just wanted to make sure there wasn't some simple all in one block that we were missing or something like that.

edit: also, is there no better way to convert the ASCIILOCADD to a string?

Lemming · Apr 30, 2014

mmmlinux said:
edit: also, is there no better way to convert the ASCIILOCADD to a string?

I haven't actually used the ASCII instruction in a 850.. Have you tried a simple copy ??, it compiles OK

mmmlinux · Jun 6, 2014

Im working on this again. Now im trying to make a function block to make this easier to work with for students. The issue im having now is it always throws an error saying that the serial port is not configured properly. ive checked and rechecked it, and its configured for ASCII just like it should be. im getting an error 4 from my acb block.

mmmlinux · Jun 6, 2014

sorry for the double post, but i just checked. it does seem to be an issue with having the serial commands in a function block. has anyone ever ran in to this issue before?

mmmlinux · Jun 10, 2014

has any one ever attemped to have ACB commands in a function block? or dealt with this in ST?

Lemming · Jun 10, 2014

mmmlinux said:
has any one ever attemped to have ACB commands in a function block? or dealt with this in ST?

I'm playing with a 850 today, so will see if I can get it working...

Lemming · Jun 10, 2014

dumped a ACB into a FB, set the ACBinput as an input parameter, and it compiles fine.. Haven't tried putting it into the PLC yet thou...

mmmlinux · Jun 11, 2014

it turns out you cant have the control variables for the ascii command blocks as local variables. they have to be global. yeah. it will compile fine, but when you run it the block will throw an error id 4.

Lemming · Jun 11, 2014

mmmlinux said:
it turns out you cant have the control variables for the ascii command blocks as local variables. they have to be global. yeah. it will compile fine, but when you run it the block will throw an error id 4.

Could still use in a FB as long as the input parameter was global ??

Serial Communication into Micro850

tim_callinan

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