Introduction - Contemporary Controls BASstat Series User Manual

1 Introduction

The BAST-121C is a member of the BASstat BACnet Communicating Thermostat series. It
provides multi-stage heating only or cooling only control in an attractive wall-mounted enclosure
with a large LCD display. Intended for use with single-mode heating or cooling units, the
thermostat can control one or two stages of heating, one or two stages of Direct Expansion (DX)
cooling, or a single 0-10V control output for either modulated heating or cooling. The BASstat is
BACnet compliant and BTL listed to ensure easy integration into BACnet networks. The BAST-
121C-BW2 communicates to a BACnet client over Wi-Fi and can be integrated into any 802.11
b/g/n Wi-Fi network. A large, easy to read LCD display indicates setpoint, space temperature and
current mode of operation using graphical icons.
The BASstat has a built-in space temperature sensor with provision for remote wired 3kΩ NTC
thermistor sensor or temperature value can be sent by another communicating device over the
BACnet network. The BAST-121C-BW2 has three relays – two for staged heating or cooling
(depending upon operating mode) and one for fan. The BAST-121C-BW2 has a single 0-10V
modulated output to control a single analog heating or cooling output device. The BASstat is
configurable locally using the Engineering Menu or via a network connection to a BACnet client.
Contemporary Controls' free BACnet Discovery Tool can be used for initial discovery and
configuration of the thermostat over BACnet. Control algorithm parameters such as proportional
gain, integral rate, stage trip points and stage widths are all configurable. This BASstat also
features configurable short-cycle protection, maximum cycles per hour, fan control and
occupancy selection. All states and pending delays are indicated by graphical icons on the
thermostat display.
The features available in the BASstat can be configured by the systems integrator to meet user
requirements in two different ways. One way is using a button sequence on the thermostat to
enter the Engineering Menu - which requires physical access to the thermostat. Optionally, the
buttons could be locked to limit user access to Engineering Menu after installation is complete.
The second method is configuring the thermostat over the BACnet network using a BACnet client
device or software such as Contemporary Controls' free BACnet Discovery Tool. Most features
available are configurable using both methods.
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