High Speed Data Logging to C-More!!!

I am having problems logging data more than once per second...

I have an Automation Direct "KOYO" DL05 PLC communicating serially with a C-More HMI. We have set the C-More up to write data to a USB card (csv) for data analysis on a PC.
The highest Data sample rate on a trend graph on the C-More is 1 sec. We would like to record 4 - 5 samples every second and then send the data array to the HMI USB card when a certain event happens. Process cycle is about 10 sec. during which we need 40 - 50 timed sample points that record time, date, name, Variable X, and Variable Y.
Could it be possible to just accumulate the data in the PLC and then write it to the HMI USB Card on command?
Does it help with data logging if I install a Flash Card in the HMI?

Thanks
O Jonsson

I don't believe you can log data below 1 sec intervals on a C-more panel. Panel holds the data to be logged in an internal buffer and then writes to USB or CF card when it reaches a certain limit. (I dont recall the exact number but look in your c-more help file under data logging/Trending for more info). USB writes are really slow on these panels. You may even lose some data (I have seen this), if your internal storage buffer gets full frequently and when the buffer data is being written to a USB card. CF writes are much faster than writing to a USB. You will notice improved data logging/writing performance, but don't believe you can log data below 1 sec intervals if you are using trend tables.

Just out of curiosity, do you get a data/Log buffer full message(or somthing similar to that)on you panel flashing intermittantly? This message clears itself when data buffer has been written to an external device (ie. USB or a CF Card).

A trick that you can try is using the alarm/events to log data. Set-up some trigger tags you want to log in to the event manager, but don't alarm them and check the log option. You might have to embed the actual data tag on to the trigger tag so it will get logged. Then use a trigger from the PLC that would cause that event to fire in the HMI, which in turn will log that tag. I have not tried using triggers below one second intervals, but you can experiment and see if this might work. This also depends on how fast your tags are being updated on the HMI panel (PLC to PANEL Comms). With serial Comms on these panels, logging 4 to 5 samples/sec might be impossible.

Hopefully someone else may know more. I am using a much faster processor (AB Controllogix)with an 12" C-more with Ethernet Comms and I am still loosing data sometimes when using the usb card. I am using max # of trend tables and each one is used to its max capacity.

Are you using the 15" C-More? I believe it has a faster processor but not sure if you can log data below 1 sec. intervals on that panel either.

Let us know if this works. You might also want to drop an email to AutomationDirect Tech support or put this post on their forum as well.

Good Luck

Orn Jonsson said:

I am having problems logging data more than once per second...

I have an Automation Direct "KOYO" DL05 PLC communicating serially with a C-More HMI. We have set the C-More up to write data to a USB card (csv) for data analysis on a PC.
The highest Data sample rate on a trend graph on the C-More is 1 sec. We would like to record 4 - 5 samples every second and then send the data array to the HMI USB card when a certain event happens. Process cycle is about 10 sec. during which we need 40 - 50 timed sample points that record time, date, name, Variable X, and Variable Y.
Could it be possible to just accumulate the data in the PLC and then write it to the HMI USB Card on command?
Does it help with data logging if I install a Flash Card in the HMI?

Thanks
O Jonsson

Click to expand...

Did you consider saving the data you want to record in PLC memory and reading it all at once every second or so from the HMI? I'm not familiar with DL05, but I assume it has indirect addressing. Try saving the data to the equivalent of N7:[C5:0.acc], where C5:0.acc is incremented at the rate you want to sample the data. Let's say you do this 10 times a second. At the end of tenth sample, set a bit that the C-More uses to trigger a a read of multiple addresses (N7:0 to N7:9), then reset C5:0. If once a second is too fast, try once every 10 seconds, reading N7:0 to N7:99.

I realize this may still not work perfectly, since there will be a finite amount of time required to read all the values to the C-More. If this time exceeds the amount of time between samples, there will be some data loss. However, you can get around this by setting up two "banks" of data - one that you'll read from and one that you'll store to while the HMI is reading the other bank.