User Guide

Using the NetLinx Module to Program the ViewStat
52
ViewStat Communicating Thermostat
It is important that the serial number array be the same length as the device array. If the serial
number array happens to be shorter, the length will be set to that of the device array and the new
members of the array will be set to the value 1. The two arrays are used to associate the ICSNet
device number to the stat number of the thermostats (set locally through the thermostat's user
interface)
Upon initialization, the VST module will retrieve the current settings of all of the thermostats on
the network. This operation may take several seconds. During this time the NetLinx program will
start receiving strings representing the states of all of the thermostat's controls. The above default
temperature scale is Fahrenheit.
The ViewStat Communicating Thermostat is an enhanced version of the OPStat with the
communication board built into the thermostat, advanced features and two displays. One display is
for temperature, mode, limit settings, lock status, fan status, network communication and humidity.
The second display is used for general text messaging for date, time, event status, and setup mode
and user notifications.
The ViewStat can monitor remote temperature and humidity, has a flexible text mode setup and
interface, and has the ability to lock local control of the thermostat.
Care must be taken when attaching to remote sensors in that the remotes can turn the thermostat
into a humidity sensor that doesn't display the temperature in the main window. When acting as a
humidity sensor, the temperature can be retrieved through the control interface only. The remote
temperature is displayed in minor sections of the main window while the remote humidity inhabits
the window center. When a remote sensor is attached, humidity changes do not generate a Change
Of State message. Also, as a humidity sensor, the mode button will change from humidity to
dehumidify and report accordingly over the control interface. To retrieve humidity, there is a
conditional poll generated upon temperature events if the temperature event came from a humidity-
supported device.
The VST_ZoneCnt is used to affect the wait period between successive commands being sent to the
thermostats. The larger the VST_ZoneCnt value is, the longer the time delay between global
commands becomes. The VST_ZoneCnt variable is associated with the serial number of a
thermostat.
To install the ViewStat module, the developer must create an array of devices and an array of
integers that stand for the serial number of the thermostat corresponding to the physical ICSNet
device. Unless otherwise needed, the serial number of all thermostats should be set to '1', to allow
the quickest response from the thermostat on global commands.
ViewStat also provides feedback from its local buttons: enter, scroll up, and scroll down. This
allows the control system to track the menu navigation if desired.
The following diagram gives a graphical view of the interface between the NetLinx program and
the NetLinx module.
FIG. 39 Interface between the NetLinx program and the NetLinx module.
NetLinx
Program
NetLinx
Module
ViewStat
Controller
Virtual
Device