User Guide

Using the NetLinx Module to Program the ViewStat

ViewStat Communicating Thermostat

The ViewStat Model

The model will define a security system as consisting of the following components:

1. System: This refers the controller and all that it controls.

2. Zone: The system will consist of one or more ViewStat zones. A zone is nothing more than an

area that can be controlled separate from other areas. Zones have their own temperature

settings.

3. Thermostat: Each zone contains a thermostat. The thermostat is used for reading temperature

and controlling when to turn on/off equipment as needed to maintain the desired temperature

setting. Thermostats can control fans, heat, A/C., etc.

4. Setpoint: There are two types of setpoints: heat and cool. When the temperature reaches or

falls below the heat setpoint the thermostat will turn the heat on (call for heat). When the

temperature reaches or exceeds the cool setpoint the thermostat will turn the air conditioner on

(call for air). These are also called comfort points. A user can keep the temperature within

these points at all times by setting the setpoint values. For example, to maintain a temperature

of 68-72 degrees the heat setpoint would be set to 68, the cool setpoint would be set to 72.

While the temperature is within this range nothing is done. Once the temperature falls outside

this range the system takes action and switches to the appropriate mode.

5. Humidify/Dehumidify: Some systems can maintain the humidity level within a certain range.

These are similar to temperature setpoints except instead of temperature control equipment the

system is controlling humidify and dehumidify equipment.

Command Interface - SEND_COMMANDs

Various system wide operations may be performed by the NetLinx program via SEND_COMMANDs

sent to the virtual device controlling the thermostats.

The supported commands are listed below.

Command Interface - SEND_COMMANDs

Command Description

'T-<tstat> COOL-<val>'

Set cool set point.

Parameters:

• <tstat> : id of thermostat/zone

•<val>:

+ = increase cool set point by one degree

- = Decrease cool set point by one degree

60-108 = new cool set point (F)

Examples:

'T-4 COOL--'

'T-1 COOL-76'

'T-<stat> COOL?'

Query for current cool set point.

Parameter:

• <tstat>: id of thermostat/zone

Example:

'T-16 COOL?'