Carmel, IN – The three most important factors in real estate are location, location, and location. Apparently the same is true of telephone lines, as the Sieper Area Water System (SAWS) in rural Rapides Parish, LA learned. This water facility has two wells and a water tower to serve the needs of its 1225 residents.
The wells are connected to the water tower via a leased telephone line which carries the signal to activate/deactivate the pumps, based on tank water level. But since the telephone line skirted two different telephone exchanges, the cost was roughly $250 per month. A radio transmitter system from Ritron enabled SAWS to replace their hardwired connections and save the monthly telephone fees.
Out With the Old
Prior to installing the Ritron Quick Talk RQT system in September 2013, the Sieper Area Water System had relied on a hardwired system for communication between the wells. The system included well #1 located adjacent to the water tower, which is equipped with a float switch. When the water level drops below that float switch, a contact closure turned on well #1.
At the same time a voltage change was sent along the telephone line to well #2 – approximately a half mile away – starting the pump to help fill the water tank. When the water in the tank reaches an adequate level, another float switch signals a contact closure at the tank, which again sends a signal to turn off well #1. A voltage change is passed along the telephone line to well #2 – this time to cease operation of the pump there.
The robust equipment was working well, however, it was expensive to operate – as the telephone line was invoiced at $250 per month. Additionally, a phone line is subject to all of the problems associated with severe weather – ice storms or hurricanes can (and do) knock down lines – disrupting the flow of information…and water.
In with the New
Wireless communications within the water system infrastructure are not new, but this was not a typical scenario either. Because the old system relied on telephone wires to carry signals, the voltage change passed along those wires was 48V – a far cry from the 0-5 volts DC which is typical for sensors and relays.
Since the old system was robust and working well, it was prudent to keep as much of it as possible, including the contact closures, float switches, and high-voltage capability (as replacing it would add cost and complexity). But rather than sending the signals to start/stop the pumps through a leased telephone line, radio signals were sent wirelessly.
This was done with a Ritron QuickTalk RQT – a 2-watt, industrial- grade radio transmitter with switch inputs. A relay capable of accepting a high level voltage change (48V) and convert it to a contact closure was installed between pump #1 and the old hardwire. The contact closure output feeds into the RQT switch input which tells the RQT to engage – and encode and send a DTMF string – via UHF1 – down the hill over the airwaves to well #2.
The signal is received at well #2 by a Ritron TeleSwitch with relays built into it. The TeleSwtich receives and decodes the DTMF string and opens the appropriate relay to start the pump at well #2.
When the water level reaches the desired level, the process is essentially reversed. The float level switch triggers a contact closure to shut off pump #1 which sends another voltage change to the relay, which converts it to a contact closure fed into the RQT switch input.
The RQT engages – encoding and sending a different DTMF string also via UHF1 through the airwaves to well #2, where the TeleSwitch receives and decodes the DTMF string, closing the appropriate relay to stop the pump at well #2.
For Savings that Ring True
The new system – comprised of a high-voltage-capable relay from Functional Devices, a Ritron RQT and a Ritron TeleSwitch cost approximately $3,000, and was installed in one day. Once operational, the lease on the telephone wire was cancelled, yielding a savings of $250 per month – or a 12-month payback.
In addition to fast payback, quick installation, and reliable service in all sorts of weather conditions – the Ritron system allows for future expansion.
Sieper Area Water System plans to build another well – in fact the land has already been purchased. When the well is drilled and brought online – bringing it into the system is easily accomplished with another RQT to signal a TeleSwitch at well #3 – and an alternating relay so that wells #2 and #3 are engage alternately to help well #1 fill the tank
Local communications equipment company Mid-State Communication Services was very helpful throughout the process. In fact it was their relationship with the local Fire department that began the process.
“Although the system is fairly rudimentary, there were some quirks – like the 48 volt voltage change” said Mid-State’s Frank J. Coe. “Once we found a relay that would accept that voltage and transform it to a contact closure, we were off and running.”
Nuts and Volts – How the System Works
The Ritron Quicktalk RQT is an industrial-grade radio transmitter with switch inputs and voice storage capability. Sieper Area Water System officials opted for the 2 watt transmitter because of its 1 mile line-of-sight capability, though the heavily forested and hilly terrain required an upgrade to directional, high gain Yagi antennas. They operate on a UHF frequency in the 450 Mhz spectrum, though VHF (150-165 MHZ) and VHF License Free MURS (5 pre-selected MURS) are also available.
Housed in a gasketed and sealed polycarbonate enclosure with built in mounting flanges, the RQT in Rapides parish is powered by a 110 VAC adaptor but also has batteries in case of power failures, though stand-alone facilities can be powered by 6 AA batteries.
Though SAWS does not use the voice recorder function, each switch/sensor circuit can also be coupled with a unique voice recording which is broadcast when the switch/sensor state changes – for example, SAWS officials could receive a broadcast message on their hand-held (or base station) radios whenever the pump from well #2 was signaled to start.
The Ritron TeleSwitch is a radio-controlled remote switch which includes a built-in VHF or UHR radio RF telemetry radio and a dual-relay DTMF decoder. The dual-relay decoder board responds to predetermined DTMF tones to activate or deactivate one or both relays which in turn are hardwired to the pump at well #2.
All electronics are housed in a sealed enclosure. Hard-wire connection of an external device is made via Heyco strain relief. Each TeleSwitch includes an antenna with BNC, AC power supply and narrow band compliant, DTX Series RF telemetry module.
While location, location, location might dictate costs for leased telephone lines, officials at the Sieper Area Water System have found a better solution to activate their well pumps. Wireless radio controls offer a simpler, economical alternative to expensive leased phone lines. The new system, built around the Ritron RQT and Ritron TeleSwitch provide a quick payback – so that SAWS can start stockpiling money to fund their new well and then seamlessly integrate it into the system.
For more information visit www.ritron.com.
Filed Under: M2M (machine to machine)