Hatching distributed automation architectures

Automation keeps fish hatcheries healthy by providing a consistent environment for fish eggs to be cultivated under artificial conditions for breeding, repopulation, and other purposes. Typically, hatchery workers release the female fish's eggs (a process known as “stripping”) and then add the male fish's sperm (milting.

By Control Engineering Staff December 15, 2008

Automation keeps fish hatcheries healthy by providing a consistent environment for fish eggs to be cultivated under artificial conditions for breeding, repopulation, and other purposes.

Typically, hatchery workers release the female fish’s eggs (a process known as “stripping”) and then add the male fish’s sperm (milting.) 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.

At Oden’s main hatchery building, Opto 22 systems manage tank water temperatures, water flow and oxygenation, and equipment status. Source: Opto 22

“Michigan hatcheries release all their fish into 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 Michigan Department of Natural Resources (DNR).

Monitoring and control systems

Klage oversees six hatcheries in the state of Michigan: 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’ process control and alarm systems, which use Opto 22 Snap Ethernet hardware as central components.

The Opto 22 systems interface with flowmeters, float level sensors, variable frequency drives, and the hatcheries’ other POW-related equipment. (POW is an acronym used by hatchery personnel to describe anything power-, oxygen-, or water-related.)

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 various hatchery buildings to automate, manage, and monitor equipment used during every stage of the fish rearing process.

“Opto systems 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 system integrator and 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 hatchery’s Windemuller-designed control and monitoring systems use Gems-brand float level switches that work in similar fashion to the ballcock assembly in most home flush toilets. The float devices are connected to Opto 22 digital input modules. 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 a Snap LCM4 (or Snap LCSX Plus) controller.

To see a video of the hatchery’s automation in action, click here .

Alarms, remote access

Alarming features also have been added so hatchery personnel receive notification if the preset high water or, more importantly, the low water mark is reached. Too little water means there is not enough oxygen to sustain the fish. The hatcheries also use system alarms to warn if too little or too much water is being supplied to any tank.

“We have the systems configured for high alarms around the 6,000 gpm mark and low alarms in the 2,500 gpm range depending on the facility and also the time of year,” says Klage. Hardware receives an alarm condition and triggers local audible horns and visual strobe lights to warn on-site hatchery personnel. After working hours, an alarm will close various contacts for remote pagers and activate a phone dialer for remote notification and quick response by on-call personnel.

For remote monitoring of the hatchery systems and equipment, Windemuller worked with the Department of Natural Resources and used OptoDisplay software to create easy-to-understand HMI screens. Source: Opto 22

While the hatcheries’ Opto 22 hardware uses an Ethernet transport protocol, the physical layer for communication varies by location—a possibility enabled by the hardware’s flexibility, says Klage and Dekker.

Some hatcheries use a serial interface from the controller to the field I/O connections (and 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 platform’s distributed nature 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. Emphasis is on performance, simplicity, and aesthetics.

As Klage explains: “At each hatchery site, there are many different buildings, such as 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 PC, so biologists and technicians can review and interpret water and equipment conditions, review control strategies, and adjust any hatchery system. Additionally, when Klage is off site, he can use PC Anywhere software to check conditions, change set points, and control various systems at the six hatcheries.

Remote control capabilities are secondary after systems related to supporting the fish and their environments. In addition to 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. A central controller and Ethernet connectivity allow biologists and technicians to monitor water and equipment conditions on any networked PC monitor, and the system can interface with these and monitor closure of auxilary contacts, providing a holistic view of all electrical equipment.


The Opto 22 systems were first specified for installation at the Michigan hatcheries just prior to 2000. Michigan DNR had Y2K compliance worries about the myriad control systems (from a mix of vendors) being used at the hatcheries.

“When I came into the picture in 1999, almost every hatchery used a different hardware-software platform,” Klage explains. Working within his budget constraints, Klage was pleased to learn that he could meet all his functionality requirements and have Windemuller integrate nearly all six systems with Opto 22 hardware for the price it was going to cost to do just one of the systems with components from a competitor.

Simplicity and easy configurability of the programming software were other major selling points. “Opto flowcharting is easy to understand, especially compared to ladder logic,” says Klage. “I also like that the I/O racks have fewer slot dependencies and that the modules are trouble-free and easy to swap out [with hot swaps, if necessary]. With some of the other systems, we would have to nearly disassemble the whole rack to replace one board.”

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– More need for outside engineering expertise, says HiTech Control Systems : Control Engineering System Integrator of the Year winner.- How system integration goals influence future: JMP Engineering ,- How to overcome the economy, grow with technology: Brock Solutions ,

Also see other articles in the 2009 print edition of the Automation Integrator guide .

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