We Hate Spaghetti Monsters

Over the years we have seen many panels similar to the one on the left. Such panels can be confusing, hard to maintain and dangerous. We can help you get these panels cleaned up. We can also upgrade your panel to an affordable Opto 22 PAC so you can have more control over your process.  

Pine Drive Water District




Pine Drive Water District is a  small water system west of Pueblo, Colorado with ~165 taps. Their surface water facility was originally constructed in 1979 and treats just 12,000 gallons per day using a typical Neptune-type rapid sand filter. The district has a considerable amount of buried water storage. This is because fire protection is priority as this system borders national forest and is thoroughly wooded.  Water is drawn from the surface water source, treated, then stored in the primary 36,000 gallon tank. From there water is pumped up to Squirrel Creek station (36,000 gal), then to Watseka station (36,000 gal) and finally to the Stansfield facility (48,000 gal).


This district has used automation since the day of its installation. Back then large relay panels were required to run the filter and system processes. Wires were dug for miles up the mountain to the tanks in order to get control signals out to the remote sites. In the late 1990's an electrician was hired to retire the old system and install Opto 22 PLC automation using the SNAP-LCSX system. Around 2005 the master controller was replaced with a SNAP-PAC-S and programmed with new features for email alarms. To connect all four sites MDS microwave radios were used to send serial data down to the master controller; a repeater radio also had to be used at the nearby Beulah Water District storage tank to reach two of the sites. The original relay cabinets are still in use today but house the new equipment. This system served the district reliably until 2015 when the radios and original remote racks began to fail. This was causing complete loss of communication to the remote tank/lift pump sites. It was determined that a complete control system and network replacement would be the best option.



Hardware

Moving to the newer Opto 22 control system did not pose much of a challenge in this case. The master rack was replaced and a SNAP-PAC-R was put in place of the S controller, which was held as a backup master. Just the one R controller runs the entire water system, all filter processes, lift pumps, raw water pumps, VFD's and level sensors.  All remote racks were upgraded to SNAP-PAC-EB2 brains. In all cases the original I/O cards were found to be reusable. The entire system was designed to communicate via ethernet. However, the radios chosen during design pushed the budget a bit too far for the district. This turned out to become a unique challenge because each site is 1.6 miles away from the next, with large elevation changes and all are among trees. This requires a powerful radio. One unique option was brought to our attention by a water board member, wide area network (WAN) radios for internet providers. 


This solution turned out to be a good match for the district's needs since security and distance were issues at the top of the list. WAN radios have excellent encryption and are designed for long distances. Cambria radios were purchased from a local distributor that surveyed the site and arranged pre-programmed radios for pickup. Once the system was delivered the radios were installed under the supervision of Stanford Engineering. Each site required as much antenna height as possible to get good signal. Antennas at each site were mounted atop ten foot poles on top of ten foot tripods. The tripods can be climbed and the poles lowered for one-man maintenance. The radio itself is mounted on the back of the antenna and powered over the ethernet connection coming from the building. Inside each building is a small box housing the power injector, backup battery and connection going to the control rack. This system created a physically large network that, to any computer, looks like a simple wire strung from site to site connecting them together on a logically small network. Such a system holds great potential and opens future avenues for expansions and upgrades. This system was also internet connected through a hardware based security system.        


Results

The original control program was modified to communicate via ethernet instead of serial and some minor logical changes were made. The control software is slated for a major rewrite in 2018 that will be part of a combined project with the nearby Beulah Water Works District. Where the new system has shown benefit is in the areas of system downtime and control system maintenance. Previously operators often lost communication with remote sites causing lift pumps to stick on and off. This problem was solved and the operators noticed an increase in communication speed. System downtime has (up to this writing) been due to scheduled upgrades and power outages.   


Control system maintenance costs have been reduced through the newly gained ability to remotely access the control network. On site costs will always be more than the cost of a remote session from the office. When a water operator notices an issue we are now able to remotely access the control system and see what is going on in real time. This allows us to determine if a technician must go to the site or, if possible, be fixed from the office. Regular control system updates are performed remotely as well as updates to the plant desktops and laptops. It is now commonplace for the operator to call and get walked through problems on the phone while we monitor. The result is a more reliable system with reduced maintenance cost.