On 10/1/2010 4:53 PM, Russell L. Harris wrote:
Check out the catalogue of a broadcast supplier such as www.bswusa.com or www.fullcompass.com. Radio stations have utilized the telephone line for remote monitoring and control of remote transmitter sites for many years. Parameters monitored include temperature, line voltage, etc. There even is a highly-reliable spark/flame detector, which is needed because of the high voltages within the transmitter. In recent years, in order to reduce costs, stations have been moving away from the telephone line to the Internet The transition from monitoring via a telephone-line to monitoring via the Internet recently has brought to market inexpensive Internet "monitoring appliances". After using a computer to set up ip addresses, reporting interval, etc., simply connect your thermocouple/rtd and your sensor contacts to a terminal strip, and plug in the power supply and the ethernet cable. There is a rather large market, and radio stations are notorious for being niggardly in allocating funds for maintenance, so the component prices are surprisingly low. I seem to recall seeing one of the appliances priced in the range of two to three hundred bucks. RLH
That first site does have some interesting equipment. It would be good to get this done without a computer, but you sure get a lot of flexibility by using an old computer. Mike _______________________________________________ Houston mailing list [email protected] http://mail.pm.org/mailman/listinfo/houston Website: http://houston.pm.org/
