AMX VST Instruction Manual page 15

Communication Control Commands (Cont.)
Command
(C1 - C12) Change-Of-State (COS) notify commands:
The ViewStat can be configured to send out a message upon a Change-Of-State (COS) for any of the variables
below. Simply turn on the COS flag for any of the variables for which the automation system needs to be kept
informed. In this way, a computer connected to Eclipse need not poll in order to see if anything has occurred -
it can simply ignore the ViewStat until it hears from it. The computer will only be notified if some event takes
place at the thermostat unit. If all COS flags are set to OFF, the Eclipse will not report anything automatically,
and the computer unit must send inquiries to the ViewStat to determine any new conditions. (This equates to a
'polling' mode, whereas with any COS flag ON equates to an interrupt mode.) There are twelve COS
indicators, which by default, are set OFF on power-up or reset.
The command format for COS notify commands is:
SN[address number or <blank> for global] C1 through C12=ON or OFF
The reply format:
SN[address number] C1 through C12=ON or OFF
Each of the COS notify commands and their responses are described in the following cells.
C1
COS - HVAC Control Circuits
C2
COS - Temperature or
Humidity
C3
COS - Remote Temperature
or Humidity
C4
COS - Contact Closures
C5
COS - Thermostat Set Points
C6
COS - Network Override
(Hold) Function
C7
COS - Thermostat Mode
C8
COS - Thermostat Fan State
(Cont.)
ViewStat Communicating Thermostat - Programming Protocol Reference Guide
Description
When any thermostat output goes from an energized state to a de-energized
state or vice versa.
Example of response:
SN1 HVAC = G+Y1+W1-Y2-W2-B-O+
When the thermostat room temperature (or humidity) reading changes.
Examples of response:
SN3 T = 72F
SN6 HUM = 36%
When the thermostat remote temperature (or humidity) reading changes.
Examples of response:
SN15 OT = 86F
SN4 OH = 57%
Applies to Monitoring Module output status.
When the thermostat Heat, Cool, Humidify or Dehumidify temperature setting is
changed by use of the up and down buttons on the thermostat.
Examples of response:
SN1 SH = 68F
SN5 SC = 78F
SN13 SHUM = 32%
SN4 SDEH = 65%
When thermostat network control has been overridden or returned at the ther-
mostat.
Example of response:
SN1 HOLD = ON
When the mode of operation (i.e. Heat, Cool, Auto, Off or Emergency Heat) has
been changed by use of the thermostat Mode button.
Syntax:
SN<address> C7=<value>
Example of response:
SN3 M = AUTO
When the fan is changed to On or Auto by use of the thermostat Fan button.
Example of response: SN2 F = AUTO
ViewStat Programming Protocol
11