AMX ViewStat - Manual (Page 48)

Set Up and Configuration
42 ViewStat Communicating Thermostat
Communications Set-Up
This is where the thermostat address is entered. Additionally, the total number of thermostats (or the highest
addressed stat on the network) is entered here to optimize communication timing. Consult a qualified service
technician before changing any of the values in this Sub-Menu (Sub-Menu not shown).
Temperature Set-Up
The first and second stage differentials can be changed, as can the display temperature offset. The differentials
set the tightness of the temperature control. If the equipment is operating too often, or the temperature swings
are uncomfortably large, the differentials can be increased or decreased respectively. The temperature offset
(calibration) allows the user to “customize” the temperature shown on the display. Consult a qualified HVAC
service technician before changing any of the values in this Sub-Menu (Sub-Menu not shown).
Backlighting Set-Up
Both displays have backlighting which can be controlled in three ways (FIG. 37). First, backlighting can be
turned on every time a button is pushed. Second, it can be configured to come on with a button push, but only
when the ambient light is below a preset value. When “only when needed” is selected, the user can select from
two levels of ambient light. Finally, it can be disabled.
Temperature Control Options
OFFSET Allows the user to offset the displayed room temperature ±3°F from true tem-
perature. This thermostat is calibrated to be within ±1°F of true temperature.
1ST STAGE DIFFERENTIAL Determines the level of control and consequently the cycle rate. Adjustable
between 0.5°F and 2.0°F, this is the value above/below the set point that the
temperature must rise (fall) to start the cooling (heating). It is also the value
below (above) the set point that the temperature must fall (rise) for the cooling
(heating) to stop. For example, if the temperature setting was 70°F and the 1st
stage differential was set at 0.5°F, in the heat mode the heat would come on at
69.5°F and stay until the temperature was 70.5°F. A small differential will result
in a tighter control, but more heating/cooling cycles.
2ND STAGE DIFFERENTIAL Again adjustable between 0.5°F and 2.0°F, this also determines the level of
control by determining when to use the 2nd stage of heating or cooling. It can
also be used to keep 2nd stage cooling from coming on too soon when 1st
stage is acting to control temperature levels or to keep costly auxiliary heat
from coming on too soon when the heat pump is sufficient.