Resource Data Management (RDM) has released the Mini Intuitive 3 Stepper EEV Case Controller for multi-evaporator single refrigeration cases. Following the release of the 3 SSR Pulse EEV variant, the newest addition can control up to three stepper electronic expansion valves (EEV). Its small-format design reduces space required for the installation as well as cost.
The same base controller as the Pulse EEV variant is used with added software capabilities and new expansion module configuration. The controller’s base inputs and outputs (I/O) are extended by three Mini Intuitive Stepper Expansion Modules with Auto-Close, each providing a stepper output and two temperature probe inputs. The expansion modules are required for the intended operation of the controller. The controller and expansion modules can be purchased together in a kit, or individually for spares or replacements. For cases featuring only two valves, a kit consisting of the controller and two expansion modules is also available.
The Mini Intuitive 3 Stepper EEV Case Controller provides outputs for lights, fans, defrost and alarming on a single refrigeration case, as well as control of up to three stepper EEV valves for the coordinated control of three evaporator sections. The Auto-Close feature of the Mini Intuitive Stepper Expansion Modules uses supercapacitor technology to close the stepper valves upon power failure.
The controller operates the EEVs via three control types: temperature control (EET), superheat control (EEV), or a combination of both (EEV/T). The controller contains logic for staggered modulation of valves during controller start-up or after defrost to reduce the impact of liquid hammer.
Two control applications – medium temperature and low temperature case control – are pre-programmed for quick and easy setup. The return and discharge air temperature of each evaporator is monitored. Alarms will be triggered based on configurable over and under temperature values. Timed delays can be set for the alarms to allow for the temperatures to return to normal to prevent premature alarms.
Superheat can be calculated in a variety of ways suiting individual requirements:
- Evaporator and suction line temperature probes only
- A pressure transducer wired directly into the controller
- Remote pressure on a network broadcast from the RDM rack/pack controller
The controller will operate five mechanical relays for fans, defrost, case lights, optional alarm and remote relay. One relay on the main controller can be operated via remote network command, such as the general purpose (GP) timer or an appropriate PLC program.
The new Mini Intuitive controller integrates seamlessly into the existing RDM suite of energy-saving features available on control system front-end DMTouch. It allows for remote defrost and case light scheduling, case performance monitoring, maximum operating pressure (MOP) protection and alarm monitoring, as well as rack shutdown support.
Key Features
- Temperature or superheat evaporator control using Stepper EEV control
- Control of fans, defrost heaters and lights
- Auto-Close feature closes stepper valves upon power failure
- Energy-saving defrost skip algorithm
- Optional pressure transducer input for pressure-temperature superheat calculation and control
- Digital inputs for general fault, case clean, and defrost enable
- Remote control options from RDM system front-end DMTouch
- Remote evaporator pressure from a rack controller
- Maximum Operating Pressure (MOP) protection and alarm monitoring
- Rack shutdown and recovery support