Echelon Mini FX - Manual (Page 102)

Mini FX User's Guide 89
// and make sure the timer is stopped:
//
nvoSwitch.state ^= 1;
autoOffTimer = 0;
}
// Finally, set the switch value according to its state:
nvoSwitch.value = nvoSwitch.state ? 200u : 0;
}
//
// when(timer_expires(....)) executes when the timer specified in
// the event condition has expired. In this example, this happens
// when the auto-off timer expires
//
when(timer_expires(autoOffTimer)) {
// Shut down the light
nvoSwitch.state = nvoSwitch.value = 0;
}
when(reset) {
InitializeIO();
LcdDisplayString(0,0, "Second Digital");
LcdDisplayString(1,0, "Sensor Example");
LcdDisplayString(2,0, "-+-+-+-+-+-+-+-+-+-+");
LcdDisplayString(3,0, "SW1 drives nvoSwitch");
}
Thermostat Example
The Thermostat example expands the previous digital sensor and actuator examples by
implementing more aspects of Neuron C programming. The Thermostat example works
not only once it is integrated with other devices in the network like the digital sensor and
actuator examples, but it automatically switches to standalone mode, if necessary, and
runs as a single, independent device.
The application implements the SFPTthermostat standard functional profile. The
application samples the local ambient temperature through the temperature sensor
supplied with both the FT 5000 EVB and the Mini Gizmo I/O board. Current ambient
temperature and setpoint values are shown on the display (where available). The
application drives the nvoCool and nvoHeat network variables using a simple
proportional controller algorithm, which is parameterized through SCPTgain
configuration properties, implements a hysteresis through the nciMinDelta
configuration property, and indicates whether the application is currently heating or
cooling through LED1 and LED2, respectively.
For brevity, the example implementation of SCPTthermostat ignores the
SCPTsetPnts (nciSetPnts) configuration property. This configuration property holds a
number of temperature setpoints, subject to the occupancy state of the controlled
environment. This example ignores this setpoint vector, and draws the temperature
setpoint from the nviSetpoint input network variable. To support standalone mode,
this application defaults the nviSetpoint variable to 21°C (69.8F).
The application first defines the device interface by declaring functional blocks, network
variables, and configuration properties. The declaration of the nvoCool and nvoHeat
output network variables use the bind_info() modifier to request that this network
variable shall use the unacknowledged service when connected with other network
variables, as required by the SFPTthermostat functional profile. Each of these
network variables has a proportional control coefficient with individually assigned
default values applied.
#include <stdlib.h>