Balluf RFID can't read more than 256 at a time

Hello

We integrated a BIS M-400-072-002-07-S4 (BIS0104) on a machine for the traceability system. It has to read a BIS M-110-02/L (BIS0044).
We are using a PLC Siemens S7-1200 with a BNI PNT-502-105-Z015 (BNI004U). We implemented and adapted the AOI available on the web page so we can be able to it.
We have been testing different combinations of addresses and number of bytes.

We can read up to 256 bytes only, starting from any address without exceeding the capacity of the data carrier (2000 bytes e.g. Address = 1743 Number of bytes = 256 ).
If we try to start to read from an address equal or greater than 2000, or if the capacity of the data carrier is exceded e.g. Addr=1990 No. of bytes= 20, we get an error (16#20). That’s normal, and we expect it. But if we try to read more than 256 bytes starting in any address without exceding the data carrier capacity e.g addr=0, we get the same error (16#20).

Does somebody knows if it is the normal operation of this processor? Or if is it possible to read the whole data carrier (2000 bytes) executing the instruction once?

Regards

Not familiar with that line of RFID readers, but some general questions:

Where are you getting that error? Is it from the PLC, maybe in the diagnostic buffer? Is it from the FB you adapted from the AOI? Is it from the diagnostics of the RFID reader?

How are you communicating to it? If the reader only occupies 256 bytes of IO memory, then it can only transmit 256 bytes of data on a cyclic basis (every scan). However, you may be able to read/write data records to pull more data out of it on an acyclic basis (only as needed). There may also be a way to chain different read commands together. I've done both with other RFID readers in the past.

It is most likely the maximum number that reader can execute for a single 'job'. You would need to verify it with the manual.

Most likely if you need to read/write more data you will need to loop through it, shifting the data each time.

I think the maximum is 254 bytes per single read.

Thanks for your responces.

mk42, the error was from the RFID reader. The reader occupies 32 bytes of IO memory, has to toggle a bit and check another to be able to read more than 30 bytes.

JOLTRON & LadderLogic. You are right, the maximum number of bytes per 'job' is 256.

I had to chain two read commands to be able to read 25 bytes starting from address 0, and 6 bytes starting from address 1226.

Best regards