Easy-STAT Applications
Easy-STAT can process multiple control strategies while maintaining its "industrial" scan rate of 10 scans per second. This ensures highly accurate and stable control.| Applicatons include: | |
Installed Easy-STAT applications
The Easy-STAT has been installed for use in a wide variety of applications, some of which are listed below.Two Pipe FAN Coil
An Easy-STAT1x is used to control a two pipe fan coil unit. One input is used for switching between cooling in the summer and heating in the winter. One output is provided to control the fan and the fan is turned on when either heating or cooling is required. A second output is used to control cooling in summer mode and heating in winter mode. An additional heating output is used for control of another heat source for all season heating needs. The heating and cooling controllers each have their own adjustable PI settings.Four Pipe FAN Coil
This algorithm enables an Easy-STAT1x to control a four pipe fan coil unit. The heating and cooling valves are modulated as required to maintain the space temperature at setpoint. An output is provided to control the fan and the fan runs continuously during occupied mode and is turned on in unoccupied mode when heating or cooling is required. Night setback is implemented, with local mode override. One of the additional inputs on the Easy-STAT can be used for either a remote temperature sensor or fan status. The heating valve is set to 100% if heating is required during unoccupied mode.Radiation of 1, 2 or 3 zones
An Easy-STAT1X can be used to control up to three independent zones of heating, with full PI control for each zone. There are two modulating outputs for zone 1 and 2, the third output is a digital output for control of zone 3. Each zone has its own schedule value to enable night setback. The local mode override on the Easy-STAT is associated with zone 1. The second and third zone are served by a remote RoomSTAT30 or equivalent.Suitable for use with hydronic radiant ceiling panels, wallfin radiation or convectors. This algorithm could also be adapted to control thermoelectric valves. Note that each Easy-STAT1X_IT_O has only 3 DOs, and therefore cannot handle 2 floating point valves.
Radiation with Exhaust Fan
The Easy-STAT1x can be used to control radiation and an exhaust fan. The heating output is fully modulating and the cooling output is turned on/off as required to maintain the space temperature at setpoint. The exhaust fan is turned on when the cooling is enabled. Night setback is implemented, with local mode override. One of the additional inputs on the Easy-STAT is used as a fan status. The Easy-STAT with this algorithm is suitable for use with hydronic radiant ceiling panels, wall fin radiation or convectors.Radiation with Exhaust Fan and Scheduled Output
An Easy-STAT1x configured with this algorithm can control the radiation and exhaust fan with the ability for the exhaust fan to be connected to the schedule output for control of the fan on a time of day basis.RadVAV
This algorithm enables the Easy-STAT1x to control a pressure dependant box for VAV heating or cooling depending on the mode of the HVAC unit as sensed by the value of a change over sensor input. The Easy-STAT uses two digital outputs to open and close a floating point modulating motor. While the HVAC unit is in cooling mode, the VAV box is the only stage of cooling. When the HVAC unit is in heating mode, the VAV box is used as the second stage of heating. The heating valve is modulated as required to maintain the space temperature at the heating setpoint. Night setback is implemented, with local mode override. Morning purge can be enabled via a supervisory controller or external input.Standard Proportional
This algorithm enables the Easy-STAT2x to control up to three stages of heating and three stages of cooling with one controller performing both the heating and cooling control. Separate proportional and integral settings are provided for heating and cooling. The Easy-STAT uses corresponding analog heating and cooling control outputs which output a voltage based on the current state of the PI strategy. The operation of the outputs can also be reversed. The analog output that is linked to the cooling controller has an option to be configured with a minimum damper position, regardless of the state of the cooling controller.There are three digital stages of heating and cooling which are either ON or OFF depending on the current output of the controller. There is an additional option to swap the first and second stages of heating when the outdoor air temperature is below a certain value. The fan output can be configured so that in day mode it is continuously on and in night mode it is only on when either the cooling or heating controller is active. Alternately, the fan can be configured so that it is on only when either the cooling or heating controller is active, regardless of whether the Easy-STAT is in day mode or night mode.
The standard proportional algorithm is available with either scheduling or I/O Bus functionality. The scheduling version allows the configuration of a weekly schedule in the Easy-STAT, with each day having its own configurable day and night options, providing energy-saving functionality. The I/O Bus version allows the configuration of up to 30 points in the Easy-STAT to be read from and written to by a supervising controller.
Proportional with 100% Fresh Air
This algorithm enables the control of up to three stages of heating and three stages of cooling with one controller performing both the heating and cooling control.The schedule state of the controller is determined by its time schedule. This state is used to control a damper, and the damper in turn controls the fan. The fan status controls whether it is in day or night mode, if the fan status is on then the controller is in day mode, otherwise it is in night mode. The controller offers different strategies for the day and night mode.
In day mode, the Easy-STAT acts as a standard PI controller. Separate proportional and integral settings are provided for heating and cooling. The Easy-STAT uses corresponding analog heating and cooling control outputs which output a voltage based on the current state of the PI strategy. The operation of the outputs can also be reversed. The analog output that is linked to the cooling controller has an option to be configured with a minimum damper position, regardless of the state of the cooling controller.
There are three digital stages of heating and cooling which are either ON or OFF depending on the current output of the controller. There is an additional option to swap the first and second stages of heating when the outdoor air temperature is below a certain value.
In night mode, the controller assumes 100% fresh air input for heating mode and the heating output is forced to a preset value so that the freezestat (the Stat/sensor in the duct) does not trip.
Proportional with Pressure Control
This algorithm provides two controllers, one for the control of up to two stages of heating and two stages of cooling, and the other for pressure control. Separate proportional and integral settings are provided for the heating, cooling and pressure control.The pressure controller has an analog output which controls the bypass damper. It outputs a voltage based on the current state of the PI strategy. It can be configured with a minimum damper position, regardless of the state of the pressure controller.
There is a maximum damper position variable, so the damper will only open to a set or specified position. This is useful when you want to reduce unnecessary noise by keeping the damper from opening fully. All controller outputs will be disabled if the FIRE input contact closure is closed. The standard proportional plus pressure control algorithm is available with either scheduling or I/O Bus functionality. If you are using the scheduling version, you can configure a weekly schedule in the Easy-STAT, with each day having its own configurable day and night variables. You can then use this feature to achieve energy-saving night setback functionality, where different setpoints are used for day and night modes.
If you are using the I/O Bus version of Easy-STAT, you can map up to 30 points in Easy-STAT to be read from and written to by a supervising controller.