Alarm Dialing with Micrologix 1500

Hi all,

I have an application that uses a Micrologix 1500 connected to a modem through an AIC module. I configured Channel 0 as half duplex slave and all I need to do is dial out when an alarm occurs and transmit the alarm. There are 21 alarms addressed from B3:10/0 to B3:11/4. Does anyone know of a source where I can sample code to set this up (never attempted before). Thanks,

Norm

I have not done this but here is something that might help


http://www.mrplc.com/kb/index.php?page=index_v2&id=67&c=12

Check out these Remote Access Modems

They aren't cheap, but they DO work. Almost anyone in here who has attempted to set up a PLC/Phone Modem connection will tell you that these things are WELL worth their cost in terms of days and days fiddling about getting the connection up and running reliably, and ease of life-cycle support. What happens when you (the guy who figured out how to make it work) is no longer about to deal to any issues that may arise?

By contrast I've used three of these kits now, they arrive with all the cables, the documentation and they plug in and work.

Half-Duplex Slave isn't the protocol you want for this kind of application. A half-duplex slave channel can't send ASCII commands, and can't transmit it's message unless polled by the master anyhow.

Describe your whole system. What's at the other end of this modem ? Are there other slave stations, and if so how many ? How often do you need this alarm data from the slave station ?

Thanks for the lead on the Modem kit. Didn't know that AB sold a magic modem.


The other end of this system is a municipal SCADA system. The remote pump station that I am programming will be calling the SCADA system and transferring alarm conditions only when alarms occur. I haven't talked to anyone on the receiving end yet as to what they are expecting. I am assuming it will be a string of zeros with a true bit somewhere in the string which can be decoded into the correct alarm. Didn't know a half duplex slave couldn't initiate a call even after reading all the AB literature relating to the subject. Must be missing something...hmmmm.

You can't begin to program or configure this until you know what devices and protocols are being used by the head end of the system.

Is this a one-of-a-kind remote station or an expansion of an existing system ?

Hi Ken,

I don't yet know what's on the other end, but I'm making the assumption that whoever (or whatever) is most likely a lot smarter or more experienced than I am. I would hope that all I need to do is to send ASCII strings. From the reading that I have done this weekend, I now know how to send ASCII strings to the modem for controlling dialing, hangup etc.

The confusion happens when I have to send a string representing 21 alarm points from B3:10/0 to B3:11/4. Thanks for your help.

Norm