Barcode reader scan time ready flag

[pszczepan 2]

Hi ! I have DeviceNet network with CJ2H as a Devicenet master. Barcode scanners are connected to DRT1-232C2. I use FB to read scanned code. Time between flag - scanner buffer is full and flag that scanned code is in PLC takes aprox. 120ms. It is quite fast internal transport and sometimes PLC doesn't have enough time to make cylinder movements - the scan time is 9,85ms Electrical gabinet is not far - I am thinking to use CJ1W-SCU21 card to read the scanner code. The question is - how much time I can save using CJ1W-SCU21 Thanks Pawel

[PMCR 66]

The answer to your question depends somewhat on how you use the SCU module. The most efficient way to do it would be to use Protocol Macro, with a Protocol Macro that kept running. Normally in a Protocol Macro, you execute the PMCR, and then return to ladder. Step 0: Read Barcode. End If you change the 'Next' column to go back to step 0, this is much faster. Step 0: Read Barcode Goto Step 0. I did some testing a few years ago on CJ1 with PMCR, and it takes about 40 ms to start a PMCR from ladder. If you leave the PMCR running all the time, you should be able to recieve much faster than your DeviceNet method. I would say that you could cut the response time to 60ms or less. The other thing that you can try with your existing setup is to increase the 'Peripheral Servicing' time. This is found in the PLC Settings on the Peripheral Services tab. Uncheck the 'default', and try a value of 50 (which is 5.0 ms). This will allow more time per scan to service communications modules, (such as DeviceNet), and may improve the response that you are getting.

[pszczepan 2]

Thanks for clues. I've already set "Peripheral Services" tab to 25ms (250). It's mostly devicenet application - you think it is to much?