Contemporary Controls BASstat BAST-221C-B2, Руководство пользователя, Страница: 4 / 36

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1 Introduction
The BAST-221C-B2 is a member of the BASstat BACnet Communicating Thermostat series. It
provides multi-stage heating and cooling control in an attractive wall-mounted enclosure with a
large LCD display. Intended for use with rooftop units (RTUs), the thermostat can control one or
two stages of heating and two stages of Direct Expansion (DX) cooling. The BASstat is BACnet
compliant and BTL listed to ensure seamless integration into BACnet networks, using
BACnet/MSTP over 2-wire EIA-485. The BAST-221C-B2 can be routed to BACnet/IP clients
using a BASrouter (BASRT-B) . 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. “221CH” thermostat models support relative humidity reading with a built-in
sensor which is shown on the display and as a BACnet object, as well as a calculated dew point
value as a BACnet object (no control action is taken based on humidity). Both models have five
relays – two for stage heating, two for stage cooling and one for fan. The BASstat is
configurable locally using the Engineering Menu or via a network connection to a BACnet client.
Contemporary Controls’ free BACnet Discovery Tool (BDT): www.ccontrols.com/sd/bdt.htm can
be used for initial discovery and configuration of the thermostat over the network. Control
algorithm parameters such as deadband, proportional gain, integral rate and trip points are all
configurable. This BASstat also features configurable fan control and occupancy selection.
Operating states are indicated on the thermostat display.
The numerous 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 in order 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 . All features available are configurable using both methods.