Hello,
I have serveral CR1000 dataloggers connected to the GPRS network with Fastrack Xtend FXT009 modems.
I noticed that sometimes, the communication with the datalogger is lost whereas the modem is still registered and connected to the GPRS network.
The solution I found is to reboot once a day the modem using the SW12 port of the CR1000 datalogger.
This solution works well but, in some of our stations, the SW12 is used to supply some sensors.
Then, my questions are:
1) Does somebody know the reason of this loss of connection that occurs sometimes with these modems? I reboot the modems once a day but is there another solution to solve this problem?
2) In some cases where the SW12 is used to supply sensors, i can't plug the modem on the SW12 to program a reboot once a day. Is there another solution to do it with the CR1000?
Thanks for your help,
Regards,
Coralie
Hi
In my experience it is normal reset the modem, at least, one time for day. But not is clear to me what could be the problem, if the modem is registered and connected GPRS. How can you have this certainty? which kind of test do you perform ? Check the modem manual or the manual of Campbell because I know that is possible to do a reset without turning off the modem with the SW12, but with sending a serial string with AT commands to the modem.
Smile
It is difficult to locate the root cause for the situation you described.
I have seen cases with some models of modems where the modems themselves locked up. The modems weren't designed to be used the way they are with dataloggers, and the modems would freeze up over time. Power cycling them is the only option.
I have also seen cases where it was a cellular network issue. Sometimes the cell connection would drop on the cell network side and the modem wouldn't notice. Thinking it still had a good connection, the modem wouldn't reestablish a connection to the network. Sometimes connections get pushed so far down the priority list on the cell network, the connection would become unusable. Resetting with an AT command might work in these cases.
Cycling power to a cell modem on a regular basis is the most reliable way to avoid bad connections. Keeping the modem off part of the day also provides benefit in reducing power consumption. The newly released version of ShortCut includes a control file for timed control of the SW12 port. You can add an external relay such as part number 7321 if you need additional switched power sources.