Sign in to follow this  
Followers 0
ECSI

Ethernet to Cellular

7 posts in this topic

For the latest CJ1M application (water supply system) that I worked on, the customer now wants to send emails daily to a process analyst. The emails will include an attached .csv file stored on the memory card in the PLC. So, here's what I want to do: 1. Program the PLC to data log process values to a .csv file on the memory card...no problem. 2. Add an ethernet module to the PLC and set it up for email use...not much of a problem. 3. Send the email out over a cellular network....YIKES!! Step 3 is what I am looking for advice on. I know Omron can only use ethernet for email, but a DSL or cable internet connection is not possible (or feasible $$$) at this location, so I am looking into using a cellular network. What I have found so far that looks promising is a Digi Ethernet to Cellular Gateway WAN unit. According to Digi tech support, it "should" work with a local cellular provider. Basically, the Digi unit would be set up to access the cellular data network and be 'always on'. When its time to send the email, the PLC ethernet unit will send out the email just like it would on a DSL or Cable network. Also, I offered to use CX-Supervisor or PLC Reporter to poll the PLC over cellular but this was rejected by the engineer. He wants the PLC to push the data out instead of relying on a computer to do the work. I guess he's looking for the Omron Blackberry technology. I guess I'm looking for opinions or confirmation that this could work before I spend a whole lot more time and money on it. Thanks

Share this post


Link to post
Share on other sites
Plain old telephone modem also isn't an alternative? For such a limited application I think it would be cheaper than choosing a cellphone. OTOH, if there isn't any nearby (< a few hundred meters) telephone connection, it could get expensive due to equipment cost for the interconnecting network. If you want more info on devices for the approach of cellular networks, the search terms "gps", "gprs" and "router" will be the obvious ones. Edited by TERdON

Share this post


Link to post
Share on other sites
Plain old telephone modem is not an alternative because the PLC can only send email over ethernet.

Share this post


Link to post
Share on other sites
Of course it only can send e-mail over ethernet. But you could convert ethernet to a modem connection with a ten year old computer, a modem, a floppy and <a href="http://www.freesco.org">Freesco</a> (or any of several other floppy-based Linux distributions). Using a windows based computer and Internet Sharing gains you the same functionality, and probably there are several other approaches... Edited by TERdON

Share this post


Link to post
Share on other sites
A computer at the site is not an option, its a reliability issue in the eyes of the project engineer. Thanks anyway.

Share this post


Link to post
Share on other sites
There are also hardware devices with the same functionality

Share this post


Link to post
Share on other sites
What you could do (we did it once on boats) is putting in a GSM modem, send a SMS to somebody when a problem occurs and immediately change the PLC's serial setup with the STUP function., and wait for a connection with polling (for instance written with CX-Lite plugins...) from the server / maintenance side... You can also keep track of the last loggings on a CF card, so even if he logs on later he can stil upload everything from the last days. If the data are limited you could write a deamon on the client side and sen everything with a PMCR in a serial board with a GSM modem but this would be a hell of a job....

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0