Fish hatcheries are facilities where fish eggs are cultivated under artificial conditions for breeding, repopulation and other purposes. Typically, hatchery workers release the female fish’s eggs in a process known as “stripping,” and then add the male fish’s sperm, a process called milting. The fertilized eggs are incubated in a controlled environment free from disease, predators and other risks. The hatched fish are then moved to raceways (artificial canals) where they mature and are sold for food, sent to aquariums or pet stores, or used for restocking.
“Michigan hatcheries release all their fish into our local rivers, lakes and tributaries to support commercial and recreational fishing and to supplement the natural population of various species,” explains Chris Klage, from the State of Michigan’s Department of Natural Resources.
Monitoring and Control
Klage oversees six hatcheries in the state of Michigan, including the Wolf Lake, Harrietta, Platte River, Oden, Thompson and Marquette State fish hatcheries. These facilities produce several varieties of salmon, sturgeon, pike, trout, splake and other species. Klage’s main area of responsibility is maintaining the hatcheries’ numerous process control and alarm systems, which utilize Snap Ethernet hardware from Opto 22, an automation products developer based in Temecula, Calif.
The Opto 22 systems interface with flow meters, float level sensors, variable frequency drives and the hatcheries’ other POW-related equipment. POW is the acronym used by hatchery personnel to describe anything power, oxygen or water related. Numerous other devices and systems manage a variety of conditions such as tank water temperatures, water flow, and oxygenation, as well as the on/off status of equipment. For example, at the Oden State Fish Hatchery, a breeding facility for brown and rainbow trout, Opto 22 Snap controllers are used in the different hatchery buildings to automate, manage and monitor equipment used during every stage of the fish-rearing process.
“First and foremost, we monitor for the presence of three-phase power to ensure that the building systems are up and running,” says Greg Dekker, project manager at Windemuller, a Wayland, Mich.-based provider of electrical, automation, communication and IT services to companies throughout Michigan. “We also monitor all of the hatchery tanks’ water levels, specifically the low water marks.”
The hatcheries’ Windemuller-designed control and monitoring systems use float level switches that work in similar fashion to the ballcock assembly in most home flush toilets. The float device is connected to digital input modules, and as the water levels change, the float rises up and down, triggering internal switches that send a signal to the module, which then communicates the readings to the controller.
Alarming features have also been added so that hatchery personnel receive notification if the preset high water or, more importantly, if the low water mark is reached, as too little water means not enough oxygen to sustain the fish. The hatcheries also generate an alarm to warn if too little or too much water is being supplied to any given tank at any given time.
“We have the systems configured for high alarms around the 6,000 gpm (gallon per minute) mark and low alarms in the 2,500 gpm range, depending on the facility and also the time of year,” says Klage. The Opto hardware receives an alarm condition and triggers local audible horns and visual strobe lights to warn on-site hatchery personnel. When alarm conditions arise after working hours, Opto 22 equipment closes various contacts for remote pagers and also activates a phone dialer for remote notification and quick response by on-call personnel.
Although all the hatcheries’ hardware communicates using Ethernet as the transport protocol, the physical layer over which this communication takes place varies by location. Some hatcheries use a serial interface from the controller to the field input/output (I/O) devices, then an Ethernet interface for programming, and to deliver hatchery data from the controllers back to a database. Other hatcheries, however, use fiber optic cable as the physical media. Future plans call for standardization of all the hatcheries on fiber optic cabling.
Distributed architectures
“The distributed nature of the Opto 22 platform is particularly important for us because each hatchery spreads out over 10 to 75 acres,” says Dekker, who worked with FishPro (a professional services firm specializing in fishery and aquatic resource engineering) to design and install the specific architecture at each hatchery that offered the best performance, simplicity and aesthetics.
As Klage explains, “At each hatchery site, there are many different buildings—raceways, clarifiers, well houses, cold storage buildings, a visitor’s center—so we have cable running underground to all these different locations. But instead of a separate controller at each location, we have an independent I/O processor talking to the local I/O and then communicating to the central Opto controller.”Once the data is received, the central controller’s Ethernet connectivity allows information to be transmitted to any networked personal computer (PC), so biologists and technicians can review and interpret the water and equipment conditions. Additionally, when Klage is off site, he can use an application program called PC Anywhere to check conditions, change set points, and take control of various equipment at any of the hatcheries.
However, these types of remote control capabilities come secondary. The main consideration is keeping all of the systems that support the fish and their environment thriving. To help ensure this, many monitoring and alarming features have been implemented. In addition to the aforementioned high- and low-water notifications, various other alarms are configured. Every piece of electrical equipment that supplies water to eggs or fish is outfitted with power monitors, and the system interfaces with these, and monitors closure of auxiliary contacts, thereby providing a holistic view of all electrical equipment.
The Opto 22 systems were first specified for installation at the Michigan hatcheries just prior to the year 2000. The Department of Natural Resources had Y2K compliance worries about the myriad of control systems (from a mix of vendors) being used at the hatcheries, and a decision was made to standardize on a single vendor.
“When I came into the picture in 1999, almost every hatchery used a different hardware-software platform,” Klage explains. Working within its budget constraints, the department was able to confer with Opto 22’s presales team and eventually specify a powerful and affordable system for each hatchery. Indeed, Klage was pleased to learn that besides having all of his functionality requirements met, he could have Windemuller integrate nearly all six systems with Opto 22 hardware for the price it was going to cost to do just one of these systems with components from a traditional programmable logic controller (PLC) competitor.
“Using Opto 22 has been very good for the department and also for the state of Michigan and the people who enjoy the great outdoors and the great fishing the state has to offer,” says Klage.
