Clearing unwanted ASCII data from RFID

so im trying to figure out a way around a little dilemma here with an RFID reader. I have older logic from another setup that works with all of the boot up string data from the RFID, but it involves timers and such and just seems overall confusing to me so im trying to redo it on my terms.

RFID boots up, it sends a bunch of ASCII data to the PLC that i dont want. to be exact 26 characters, then another 1 character. Then the RFID card character data comes through to the PLC properly after you swipe a card over the reader twice. So what i need in the end to be doing is looking at a swipe of an RFID card, thats going to output 11 characters of data, example 0:12345678, with an end of termination hex character of 0D (ASCII ^M on a ML1400) to make up all 11 characters. So what I would like to do is read all of that boot string data into the PLC from the buffer, then delete it and have a fresh clean slate for the first swipe of the RFID card.

attached is a screenshot. Processor is an ML1400. First time dealing with ASCII instructions so be warned, in the attached screenshot i think im on the right track, but full disclaimer i could be way off.

Have you tested your logic out?
I would connect Windows HyperTerminal to the controller to test if you do not have a spare RFID. You would be able to mimic the signals coming in to the port.
Download Hype Terminal:
http://download.cnet.com/Hype-Terminal/3000-2086_4-76158601.html

Regards,

I have. I am able to use a spare RFID station I have available to me. My issue is that upon bootup this scanner spits out a boot string and i need to be able to take it into the PLC and just delete it so that the RFID card data that comes in after it is seen immediately on the first swipe of the card.

Does your PLC control boot up of the scanner? If not, wire it so that it does then you'll always know when the unwanted data will be arriving and can deal with it accordingly.

Why not use a greater than 11 on your buffer to clear the buffer? This should then take care of the initial characters send upon startup of the RFID.

Just a thought,

shawn_75 said:

Does your PLC control boot up of the scanner? If not, wire it so that it does then you'll always know when the unwanted data will be arriving and can deal with it accordingly.

Click to expand...

it does not. I know that the unwanted data arrives on boot up of the RFID scanner. What i cant yet figure out is how to deal with it accordingly.

gclshortt said:

Why not use a greater than 11 on your buffer to clear the buffer? This should then take care of the initial characters send upon startup of the RFID.

Just a thought,

Click to expand...

i just tried as you said.

put a GRT instruction in and it was set to if the ABL instruction found more then 11 in its R10 control data file .POS then it would trigger an ACL, but im still having the same issue.

i assume that once ASCII data is sent TO the PLC, it has to be dealt with in some way? or can it just be kept in the buffer then deleted?

screenshot

So my question is. After an ABL I see that I will get the amount of characters returned. Now those characters, do they need to be brought into the PLC via an ARL and then deleted if they aren’t needed? Because what I’m attempting to do is then use an ACL right after an ABL and trigger the ACL off of an NEQ comparing the R10 data file attached to the ABL. If the amount of characters that I’m after isn’t found in the ABL, I’d like to just clear them from the buffer. But it’s not seeming that it works out that way.

Set your ACL Receive Buffer to "Yes" in your rung 002

shawn_75 said:

Set your ACL Receive Buffer to "Yes" in your rung 002

Click to expand...

well, i cant say that it wasnt in the manual because i just re-read that section and it does say you need to set them to "Yes". thanks for the heads up, glad it should all work now and it wasnt a larger logic issue.