J
Hi. Me again.
Another project we are working on with our local municipality requires long distance communications between a Master PLC (at a standpipe) to several slaves at the pumphouses.
In the past, the city has used 300 Baud telephone company circuits. Most PLC's don't even go this low anymore, so we are looking for suggestions on what would be the best method.
We have been looking at spread spectrum RF, but don't know about reliability, or vulnerability to vandilism. (big towers make great target practice, especially when some of the sites are in wooded areas.)
The only other affordable option I can think of would be leased lines. Problem is, the local phone company only knows how to provide you with the line. What type of hardware should we use? What type of topology (bus, star...?) and what are the pros/cons. Would we terminate everything at the master PLC and use a concentrator?
Just for more info, the PLC's will most likely be Modicon, using the modbus port (unless someone thinks the MB+ might be a better option), and the distances will vary from 1/4 mile to 4 miles or so.
Thanks in advance
Jody Gallant CET
Shadcomm Ltd.
Another project we are working on with our local municipality requires long distance communications between a Master PLC (at a standpipe) to several slaves at the pumphouses.
In the past, the city has used 300 Baud telephone company circuits. Most PLC's don't even go this low anymore, so we are looking for suggestions on what would be the best method.
We have been looking at spread spectrum RF, but don't know about reliability, or vulnerability to vandilism. (big towers make great target practice, especially when some of the sites are in wooded areas.)
The only other affordable option I can think of would be leased lines. Problem is, the local phone company only knows how to provide you with the line. What type of hardware should we use? What type of topology (bus, star...?) and what are the pros/cons. Would we terminate everything at the master PLC and use a concentrator?
Just for more info, the PLC's will most likely be Modicon, using the modbus port (unless someone thinks the MB+ might be a better option), and the distances will vary from 1/4 mile to 4 miles or so.
Thanks in advance
Jody Gallant CET
Shadcomm Ltd.