Contemporary Controls BASstat BAST-221C-B2 Installation Manual

BACnet MS/TP configuration requires setting the baud rate (9.6kbps – 76.8kbps) or
using the default baud rate of 38.4kbps. A unique MS/TP MAC address is required to
distinguish each thermostat from other MS/TP devices on the bus (default MAC
address is 1).

When more than one BASstat is installed at the same time on the same EIA-485 bus,
their MAC addresses must be configured prior to communicating with all thermostats
on the MS/TP bus, or communication will fail due to duplicate MAC addresses. The
MAC address can be set from Engineering Menu item (Addr) with values of 1 - 127.
The baud rate can be set from menu item (bAud) 9.6kbps – 76.8kbps. A unique
Device Instance number throughout the entire BACnet internetwork is also required
to distinguish the device from all other BACnet devices. Device instance can be
modified in Engineering Menu items (dEVH) – high bytes and (dEVL) – low bytes;
Device Instance = (dEVH)*1000+(dEVL). Max masters setting can be set from menu
item (AdrH), default value is 127.

To enter the Engineering Menu, hold down the UP and DOWN buttons
simultaneously for 5 seconds. Use the UP and DOWN buttons to navigate through
the menu and change menu item values. Use the MODE button to enter a menu item
and accept/confirm a selected value. To exit the Engineering Menu, navigate to
menu item (End) and press MODE, or the menu will exit automatically when not
used.

The BASstat series of BACnet-compliant wired communicating thermostats are BTL
listed to ensure effortless integration into BACnet MS/TP (EIA-485) networks. These
thermostats are suited for single or multi-stage heating, cooling and ventilation binary
output control applications such as RTU or AHU. Configurable control algorithm
parameters allow adaptability to the specific application. Adaptive control algorithm
applied to multi-stage on/off control saves energy and ensures seamless comfort for
the occupants. Built-in temperature sensor, input for remote temperature sensor, or
temperature override network command from Building Automation System.
Occupancy status can be set from thermostat buttons or over the BACnet network.
Thermostat buttons are optionally lockable to prevent unauthorized control. Digital
display with graphical icons is easy to read and understand. Several icons indicate
parameters such as: Active Mode, Cooling stage 1 or 2, Heating stage 1 or 2,
Ventilation Only, Fan Active, Occupied / Unoccupied state, and Clock icon to indicate
Short Cycle Delay or Max Cycles per hour active waiting state. Four main control
types are available: Cooling and Heating with Auto-changeover, Cooling or Heating
with Manual-changeover, Cooling only, and Heating only. These control types are
selectable from Engineering Menu (tyPE) or BACnet object MSV8.

Electrical (Class 2 Circuits Only)
INPUT AC only

Voltage (±10%): 24 VAC
Power: 5 VA
Frequency: 47-63 Hz

Environmental

Operating temperature: 0°C to 60°C
Storage temperature: –40°C to +85°C
Relative humidity: 10–95%, non-condensing

Functional MS/TP
Physical Layer: EIA-485

Cable length limit: 4000 ft / 1200 m @76800 bps max
MS/TP data rate (bps): 9600 – 76800 bps

MS/TP node limit: 32 full-load devices max per segment

The BASstat requires 24 VAC while drawing no more than 5 VA of power. The
recommended conductor size is 16–18 AWG or up to 2x 1.5mm wires.

WARNING: Internally, this device utilizes a half-wave rectifier and therefore can only
share the same AC power source with other half-wave rectified devices. Sharing AC
power with full-wave rectified devices is NOT recommended. Devices powered from
a common AC source could be damaged if a mix of half-wave and full-wave rectified
devices exists.

The BASstat does not provide End-of-Line termination. If the BASstat is the first or
last device on the MS/TP bus, a termination resistor (120Ω) must be applied across
pins 16 and 17 of the EIA-485 input terminal to avoid network errors or failure.

BASstat mounts directly onto wall, panel, standard 65×65mm junction box (hole pitch
60 mm) or standard 2×4 inch vertical junction box (hole pitch 83.5 mm). To mount on
electric box, separate back plate from the controller by loosening the screw. Align the
mounting holes of the back plate to the screw holes of the electric box. Fix the back
plate to the electric box using screws. Suggested screws for use are Phillips wide
“truss head” or “washer head” screws #6-32 x ¾” (20mm). Wire the controller and
mount on top of back plate. Secure by tightening the mount screw at the bottom.

WARNING: DO NOT let the back-mount screw heads rise above the back plate or it
may touch the circuit board and cause a short.

BAST-221C-B2 BASstat

BACnet® MS/TP Thermostat Installation Guide

Installation

Mechanical Drawing Operation Overview

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 device over the
BACnet network.

The default control type is Cooling and Heating with Auto-changeover. Four main control types are available: Cooling and Heating with Auto-changeover, Cooling or Heating

with Manual-changeover, Cooling only, and Heating only. These control types are selectable from Engineering Menu (tyPE) or BACnet object MSV8.

User-side comfort control is accomplished with six buttons – mode (Heat, Cool, or Ventilation – dependent on control type chosen from Engineering Menu (tyPE) or BACnet

object MSV8), fan, raise, lower, set, and power. There are also options to lock select buttons or all buttons on the thermostat. A large LCD display indicates setpoint, space

temperature and current mode of operation using graphical icons.

By default, the BASstat thermostat will not provide Fan output signal when in Heat Mode since most HVAC comfort systems provide their own Fan control signal based on a
delay after a call for heating. This can be configured from Engineering Menu item (F-Ht) or BACnet object BV15 with a default value of 0. To enable Fan control signal output
for heating, set this value to 1.

Reset settings can be performed from Engineering Menu item (rSt) which will reset all parameters including communication (MAC and Device Instance) and all control
algorithm values back to factory-programmed defaults.

For complete datasheet and details on BASstat, support, or compliance information, please download our BASstat User Manual and Data Sheet at:

https://www.ccontrols.com/basautomation/basstat.php

Contemporary Control Systems, Inc. reserves the right to make changes in the specifications of the product described within this manual at any time without notice and without obligation of Contemporary Control Systems, Inc.
to notify any person of such revision or change.

TD150900-0IA