User Guide

ViewStat Programming Protocol

ViewStat Communicating Thermostat - Programming Protocol Reference Guide

Command Set Syntax

SN#[COMMAND][? OR =][VALUE] <CR>

Upper or lower case letters may be used for all commands. Invalid characters will immediately

invalidate a command, so the use of delete is not allowed (applies mainly when interacting with the

thermostat using HyperTerminal).

All Viewstat commands will begin with the characters

SN. Immediately following the SN, without

any intervening spaces (blanks), will be the address (

#) from 1 to 64 of the Viewstat with which you

are communicating. Single digit addresses may be sent as a two digit address with a leading zero.

Omitting the address, or using a 0 (zero) in place of a space makes the command global, and all

connected thermostats will respond. Following this initial command sequence, spaces may be

inserted at this point only, for clarity between commands. The next portion is the command or

variable

[Command]. The table below describes the available commands. The next portion

[? Or =] is the action to be performed: ? corresponds to "state your value", = corresponds to "set

your value". Spaces are allowed between the command and the action. The final portion,

[Value], is used only if a command or variable is to be set.

The value must follow the action with no intervening spaces. A carriage-return

<CR> (Enter) is

used as the terminator for the command string. Line feeds (

LF) should not be sent with commands

as this is a recognized ASCII character and invalidates any command received between the line

feed and the next carriage return.

EXCEPTIONS: The command SN? or SN0? will respond with all connected thermostats returning

their address. The command

BLTON performs its intended action without the need for a value.

Command Response Syntax

The ViewStat responds by supplying the information requested or by confirming the completion of

an action command. The response syntax is generally the same as that used for commands, but no

spaces separate command, action or value. Responses are sent in upper case ASCII format. Details

of the response can be found in the detailed description section for each command. Should a

command not be recognized, no response will be forthcoming - there is no

ERROR message.