get the data outta here

[russrmartin]

This is less a PLC question than it should be. I need to get some information out of a CLogix 5000. I need to track the amount of time a machine runs without a Thermal Oxidizer(track pollution control. This needs to be accurate to a tee, as it will be reported to the WDNR. I was thinking of just monitoring the run status bit for the machine, and the Thermal Ox Running bit in the PLC, and use them to trigger a timer value. I thought I could do this all in Excel, but the problem there is that if I lose my connection to the PLC, the values in excel stay in their last state. The problem with doing the calculations in the PLC is the fear of a program download contaminating the data. How would you guys do something like this? I'm very green at this, and all suggestions are welcome. Thank in advance.

Russ

 

[Ken Moore]

We have a similar situation, local EPA requires us to track all enviornmental equipment down time, running parameters and utilization, and report it on a quarterly basis.
Our permits specify how often everything must be recorded and tracked.

We ended up using a SCADA system to capture and historize the data. The data is backed up every night and stored to tape. We could not meet our permit requirements with anything else we could think up.

A small SCADA system (minimum point) is not that expensive, when the the alternative is to shut down your facility.


Ken

 

[grs]

To me it doesn't sound like this has to be a continuously viewed data stream. IE, you don't need a fancy trend to show it. If that's the case, why not just use the PLC to do the tracking with a timer, like you suggested, and set up excel to start a spreadsheet with a scheduled task, say every morning at 8:00 am. The spreadsheet can have VBA code that will read the PLC data, put it in a nicely formatted report, print it out for the WDNR, and close excel.

 

[russrmartin]

Sounds good to me

GRS,

This is exactly how I would like to do this. My main question now is can I run microsoft excel as a service? The PC I would most like to use needs to be left for production logons etc. Can excel be run as a service?

 

[akreel]

To me it doesn't sound like this has to be a continuously viewed data stream. IE, you don't need a fancy trend to show it. If that's the case, why not just use the PLC to do the tracking with a timer, like you suggested, and set up excel to start a spreadsheet with a scheduled task, say every morning at 8:00 am. The spreadsheet can have VBA code that will read the PLC data, put it in a nicely formatted report, print it out for the WDNR, and close excel.

Except that he said he was concerned that a download might corrupt the data. That is a valid concern with ControlLogix.

I haven't tried this yet with CLX, but you should be able to create a static data element that won't be changed by a download. I would increment that element based on time and your process variable. You shouldn't be able to accidentally manipulate that data, then.

AK

 

[grs]

Russ,

The applications I've done I haven't had Excel running the whole time in the background. I just used the windows 2000 scheduled task to execute the excel spreadsheet I made at a certain time every day.

As akreel mentioned, this doesn't solve the problem of a download clearing the memory. You could always put the keyswitch in 'run' mode to solve this, or invest in RSSecurity Server.

grs

 

[Mark_H]

RSSQL will work, and can log your data into a simple database running MS Acess any where on your network. Using Excell and RSLinx is torture. RSSql will save transactions untill they can be dumped into storage. Once set you can almost forget about it.

 

[robert denton]

Russ,

I have run into the same trouble. Our fix was to set up interger files that tracked total (in your case minutes) for each hour. After 24 hours, the first set is moved, and the new run starts. This allows you to run a excel sheet with DDE to record the events. I was working on a way to automate the excel spreadsheet so that no one had to be present for the run. I had a macro that saved the file to a server folder tagged with date and time stamp. I never quite got it to work in total auto, but chould print my report during a fifty nine minute window, without loosing any data. One report per day, with lots of key data for our system. The bean counters loved it. Production managers hated it. For me, it was just another fun project.

If you are intrested in a little more detail give me a shout. I have sense changed jobs, and don't have the program files or the spreadsheet, but the basic layout is streight forward.

Oh yeah, my new boss wants the same type of report. I just have to get a SLC504 on ethernet, and run a network to support it all.