CONTEMPORARY CONTROLS BAST-421C-B2 BACnet Communicating Thermostat User Manual

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BAST-421C-B2  

BACnet Communicating Thermostat for Modulating Fan Coil Operation  

BASstat  

Modulating Thermostat  

User Manual  

#UM-15093000-AA2  

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General	Details
Name	CONTEMPORARY CONTROLS BAST-421C-B2 BACnet Communicating Thermostat User Manual
Make	CONTEMPORARY CONTROLS
Language	English
Filetype	PDF (Download)
File size	0.65 MB

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• ALL THERMOSTAT INSTRUCTIONS & USER MANUALS
• CONTEMPORARY CONTROLS

CONTEMPORARY CONTROLS BAST-421C-B2 BACnet Communicating Thermostat User Manual Overview

Summary of Contents

• Page 1: BACnet communicating thermostat for modulating fan coil operation Modulating thermostat User manual
• Page 2: Trademarks BASautomation, Contemporary Controls, and CTRLink are registered trademarks of Contemporary Control Systems, Inc. BACnet is a registered trademark of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Powered by Sedona Framework is a trademark of Tridium, Inc. Other product names may be trademarks or registered trademarks of their respective companies. Copyright © Copyright 2021, by Contemporary Control Systems, Inc. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language or computer language, in any form or by any means, without the prior written permission of Contemporary Control Systems, Inc. Disclaimer 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.
• Page 3: Introduction Features and benefits Product image and main features Specifications Inputs Outputs Communication Electrical Environmental Electromagnetic compatibility Mechanical (all dimensions are in mm)
• Page 4: Features and benefits include a stand-alone thermostat algorithm or full BACnet network control. The device is BTL listed with a B-ASC device profile for integration into BACnet networks. It operates on a 24VAC power input and supports BACnet MS/TP with baud rate selections up to 76.8kbps. The thermostat is suitable for 4-pipe modulating heat/cool control applications with manual or automatic changeover. It features an adjustable algorithm for modulating valve control and effective run time accumulation for energy consumption metering. Control parameters such as deadband, proportional gain, integral rate, and cycle time are fully configurable. There are adjustable minimum and maximum set point ranges, with three options for temperature reading. Occupancy status can be switched locally, by a separate occupancy sensor, or via BACnet network command. The device includes separate adjustable occupied and unoccupied set points for heating and cooling mode.
• Page 5: Specifications Inputs Temperature display range: -22 to 248 °F (-30 to 120.0°C) with suitable sensor. Temperature display resolution: 0.1°F (0.1°C). Temperature accuracy: ±1.8°F (±1.0°C) with all outputs off. Setpoint range: 32-122°F (0-50°C) in 0.5° increments. Provision for external occupancy sensor. Provision for NTC Type 3kΩ thermistor. Outputs Relay output: SPST 2A at 30 VAC with inductive load. Analog outputs: 0-10v modulating AO1 (cooling), AO2 (heating). Minimum contact life: 100,000 cycles. Communication Protocol compliance: BACnet/MSTP with B-ASC, BTL Listed. Physical layer: RS-485 2-wire. Electrical Supply voltage and current: 24 VAC (±10%) 5 VA. Power source class: NFPA 70 (NEC) Article 725 Part III Class 2.
• Page 6: Environmental conditions include operating temperature, storage temperature, and relative humidity. The operating temperature ranges from 32 to 122°F (0 to 50°C). The storage temperature ranges from 14 to 140°F (-10 to +60°C). Relative humidity is 5 to 95% non-condensing. The BAST-421C-B2 complies with the Electromagnetic Compatibility (EMC) Directive 2004/108/EC. It bears the CE mark in accordance with EMC provisions. Electrostatic discharge immunity is tested according to IEC 61000-4-2. Radiated, radio-frequency electromagnetic field immunity is tested according to IEC 61000-4-3. Electrical fast transient/burst immunity is tested according to IEC 61000-4-4. Voltage surge immunity is tested according to IEC 61000-4-5.
• Page 7: Mechanical dimensions are provided in millimeters. The device can be mounted directly onto a wall, panel, or standard junction boxes. It fits a 65×65mm junction box with a hole pitch of 60 mm. It also fits a 2×4-inch vertical junction box with a hole pitch of 83.5mm. The width of the device is 94mm. The height is 118mm. The depth measures 34mm.
• Page 8: Installation instructions for the BASstat 421C-B2 include surface-mounting on an interior wall, away from direct sunlight or air movement. The display can be removed from its base by loosening a small Philips screw. The base can be mounted onto the wall with appropriate fasteners, aligning with a single-gang electrical junction box if used. Two terminal blocks provide all field connections, with BACnet MS/TP data communication at terminals 16 and 17. The BASstat does not provide End-of-Line termination; a termination resistor must be applied if it is the first or last device on the MS/TP bus. Remote sensor input is located at terminals 13 and 14, while the remote occupancy input is at terminals 14 and 15. The BASstat is powered by a Class 2 compliant power source, accepting 24VAC with a maximum of 5VA power consumption. It should comply with the National Electric Code (NEC) article 725 and carry a listing from a regulatory agency. The BASstat uses a half-wave rectifier and can share the same AC power source with other half-wave rectified devices. Sharing AC power with full-wave rectified devices is not recommended.
• Page 9: Connect the HOT side of the secondary to the 24 VAC high side input on the BASstat and the LO side to 24 VAC common. Devices powered from a common AC source could be damaged if a mix of half-wave and full-wave rectified devices are both present. If you are not sure of the type of rectifier used by another device, do not share the AC source with it. Wiring: 14 to 22 AWG wires or 1.5mm² wires. Wiring diagram.
• Page 10: Operation involves user-side control with six buttons: MODE, FAN, UP, DOWN, SET, and POWER. A large LCD display shows setpoint, space temperature, occupancy status, and current mode of operation. System modes available depend on the control type chosen from the Engineering Menu or BACnet object. Button operation may be limited by the installation engineer, especially if controlled over a BACnet network. The POWER button toggles between ON or OFF states to start or stop the thermostat. Pressing any button at power ON starts User Mode operation. The MODE button toggles between different HVAC operating modes such as Cool, Heat, or Ventilate. The UP/DOWN buttons adjust the temperature setpoint or toggle fan modes. The SET button allows toggling between Occupied or Unoccupied states outside of scheduled operation. If no button is pressed for 10 seconds, the thermostat returns to the normal display with the last known setting.
• Page 11: User mode thermostat operation includes the following key points: Normal display shows the current room or set-point temperature. The desired temperature can be set using the Up/Down arrows. BACnet objects can be used to write or force the setpoint to a desired value. The working mode can be selected by pressing the MODE button and using the Up/Down button. Available modes include cooling, heating, or ventilating. The fan mode can be changed between auto or continuous on. In auto mode, the fan operates automatically; if flashing, it is under a delay timer. When the fan icon is spinning without auto displayed, the fan runs continuously. Occupancy settings can be toggled between occupied and unoccupied using the UP and DOWN arrows. The SET button may be locked to prevent user control of occupancy state.
• Page 12: User mode flow chart Control type Control type, system mode and algorithm configuration System modes available to the user are dependent on control type. 4-pipe cooling or heating with auto changeover is the default control type in this thermostat. The thermostat will switch between cool and heat modes automatically. In this control type, the user will be presented with a choice of heat or ventilation@heat when in heat mode. 4-pipe cooling or heating with manual changeover requires a command from the user or BACnet supervisor to switch modes. The user can choose to switch between cool and heat modes using the mode button. BACnet controlled allows the thermostat algorithm to be bypassed and controlled over the BACnet network. The logic executing in the supervisor can control the thermostat over the BACnet network.
• Page 13: Cool only and heat only modes are control types listed in the BACnet object but are not available for use. Control type is configurable by the installer using Engineering Mode Menu or BACnet supervisor. The default control type is set to 4-Pipe cooling or heating with auto changeover. Manual changeover can be used to prevent excessive automatic changeover between cooling and heating system modes. A PID adaptive control algorithm is applied to minimize overshoot. The default control type allows the thermostat to operate as fully stand-alone. Control type can be selected in (tyPe) or [MSV8]. Occupied and unoccupied cooling and heating set points can be set individually. The minimum control analog output voltage for the modulating valves is set to 0 volts. A current temperature value can be assigned through BACnet AV-1 to replace the onboard temperature sensor value.
• Page 14: Floating deadband allows temperature setpoints to adjust while maintaining the configured deadband. Minimum cooling setpoint is confined by the low limit plus deadband, with a default of 18°C/65°F. Maximum heating setpoint is confined by the high limit minus deadband, with a default of 25°C/77°F. Lowest fan speed is the default speed after a control action in AUTO mode, with options for fan operation. If set to Stop (1), the fan will shut off after a control action plus a 2-minute delay. If set to Low (2), the fan will run continuously after a control action. Fan mode can be toggled between AUTO or ON using the FAN button or BACnet object. By default, fan mode is set to Auto(1), with the AUTO icon displayed. To set the fan to ON mode, change the BACnet setting to Low(2), causing continuous operation. The FAN button can be locked to limit user access or programmed to default at the end of an occupancy cycle.
• Page 15: Occupancy setting can be defined in several ways. Occupancy will be detected by ESI contact by default. Energy Savings Input (ESI) is a dry contact input for communication from a customer-supplied occupancy sensor. Occupancy status can be set by a BACnet supervisor using writable object ESI Contact Definition. User control of occupancy state is allowed from the SET button if E12/AV18 Lock has the ESI Contact disabled. Occupancy Status is a read-only BACnet object indicating current occupancy state. When in unoccupied state, a Moon icon will be displayed on the LCD, and the thermostat will change set-point temperatures. When the state changes back to occupied, the thermostat will return to the occupied set-point values, and a sunlight icon will be displayed. Thermostat configuration can be performed using the engineering menu or by controlling BACnet objects. It is highly suggested that engineering mode be operated by trained installers only.
• Page 16: Menu item selection allows access to various settings. The display will revert to User mode after 10 seconds if no action is taken. Settings require confirmation using the MODE button to be saved. To exit Engineering Mode, select the End menu item and press the MODE button. Alternatively, inactivity for 10 seconds will return the thermostat to User mode.
• Page 17: Engineering menu items table Deadband Unoccupied (ESI) cooling set point Unoccupied (ESI) heating set point Integral time and output cycle time Low limit for temperature set point High limit for temperature set point Current temperature offset Proportional band or stage width Stage differential Bit definition
• Page 18: °C scale °F scale Description of digital sensor contact definition Present temperature is obtained from built-in or remote temperature sensor Display present temperature value or current set-point for LCD Door or windows contact definition Lowest fan speed in auto fan mode Output percentage (not used) Device instance number - high and low bytes Max master - the highest allowable address for master nodes Cooling and heating stage delay settings
• Page 19: °C scale °F scale 4-pipe cooling or heating manual changeover 4-pipe heating and cooling auto changeover Minimum output for AO2 Communication heartbeat minimum rate Humidity control proportional band or stage width 2 Maximum heating temperature setpoint Minimum off time Self-diagnostic
• Page 20: Changing values requires unlocking modification for communication parameters. The device instance number is calculated using devH and devL. The lock function setup enables or disables features in the thermostat. The first 10 bits of the lock register are used for toggling features. Bits are represented by their decimal values and can be added or subtracted. The lock function includes buttons such as MODE, DOWN, UP, and POWER. Unlocking all features is indicated by a value of 0. Each button has a specific decimal value associated with it for locking. The default value of 64 maintains occupancy selection over BACnet. Modification for communication parameters is locked with a value of 256.
• Page 21: BACnet objects and network configuration Transmission types Physical layer: EIA-485 Protocol: BACnet MS/TP Baud rate: 38400 bps (default). MAC address: 1 (default) Device instance: 700001 (default) All configuration parameters are settable through use of the buttons on the thermostat by entering the Engineer Menu. Configuration can also be altered using BACnet commands. Network command-based configuration can be accomplished using a Wi-Fi enabled device and Contemporary Controls’ free BACnet Discovery Tool. BACnet Object Table BAST-421C-B2 Object name: Device 700001
• Page 22: Current humidity range is 0.0 to 100.0% RH. Current dew point is measured in °C/°F. Current CO2 reading is from 0 to 3000 ppm. Control valve feedback is available for modulating and floating output. Cooling temperature setpoint ranges from 32.0 to 122.0°F. Heating temperature setpoint ranges from -99.9 to 999.9°C/°F. Running time of valve is recorded in hours, minutes, and seconds. Unoccupied cooling setpoint ranges from 25.0 to 30.0°C. Deadband is adjustable from 0 to 18°, with a default of 4°. BACnet assigned current temperature ranges from -99.9 to 999.9°C/°F.
• Page 23: Unoccupied heat setpoint Unoccupied heating setpoint Integral-cycle time Minimum output voltage in digital value when reach low limit for AO1 Span offset for AO1 Low setpoint limit High setpoint limit Temperature offset Proportional band or stage width Stage differential
• Page 24: Type and instance of objects are defined with readable and writable attributes. The document outlines button definitions including mode, down, up, fan speed, power on/off, set, ESI contact detection, and door/window contact detection. Modification for communication parameters includes baud rate and MAC address. Control outputs are described in terms of percentage for modulating or floating control output. The MAC address range is specified from 0 to 4194302. Device instance and humidity offset values are also detailed. The humidity offset value is specified for CH models only, ranging from -30.0 to 30.0 %RH. Examples for locking functions and control outputs are provided for clarity. The document emphasizes the importance of unlocking modification for communication parameters before making changes. Reserved or unused bits are noted for future use.
• Page 25: Object name Cooling short cycle delay Cooling maximum cycles per hour Heating short cycle delay Heating maximum cycles per hour Minimum output voltage in digital value when reach low limit for AO2 Communication heartbeat minimum rate Humidity proportional band-stage width Stage differential for humidity control output CO2 offset value Minimum cooling setpoint
• Page 26: Type and instance of objects are defined, including readable and writable attributes. Maximum fan output is specified for different fan modes. Low, medium, and high fan speed settings are provided for modulating fan applications. Minimum off and on times are set between 0 to 600 seconds. Integral cycle time and output are mentioned. Set points for humidity control range from 0 to 1000. Dew point temperature set points range from -999 to 9999. Occupancy status indicates whether a room is occupied or unoccupied. Window and door status is defined as open or closed. Cooling and heating status indicates whether the system is on or off.
• Page 27: Type and instance of objects are defined. Status of digital inputs is indicated for inputs 3 to 7. Fan status is monitored with on/off indicators. Flow switch and trip status are reported. Differential pressure switch status is included. Alarm statuses for trip, filter dirty, and smoke/fire are provided. Valve status is monitored with on/off indicators. Frozen alarm status indicates normal or after hour conditions. Occupancy contact definitions are specified. Temperature scale options are available in Celsius or Fahrenheit.
• Page 28: Relay control settings include on/off control for multiple relays. Room occupancy setting indicates whether the space is occupied or unoccupied. Fan output for heating can be enabled or disabled. Fan mode options include auto, low, medium, and high settings. System mode can be set to cool, heat, or ventilation. Sleep function allows for various sleep durations. Temperature source can be selected from built-in, remote, or BACnet assigned. Lowest fan speed is defined for auto fan mode. Fan speed status indicates current operational speed. Communication settings include heartbeat functionality.
• Page 29: Baud rate options include 9600 bps, 19200 bps, 38400 bps, 57600 bps, and 76800 bps. Display options for the LCD include various combinations of temperature, CO2, and relative humidity. Control type selection includes options for 4-pipe cooling or heating manual changeover and auto changeover. Contemporary Controls warrants this product to the original purchaser for two years from the shipping date. Products returned for repair are warranted for one year from the date of repair or for the remainder of the original warranty period. CC will repair or replace the product at no charge if it fails to operate in compliance with specifications during the warranty period. The customer is responsible for shipping the product to CC for warranty service. CC's warranty does not cover products damaged by abuse, accident, misuse, or incorrect installation. User modifications may void the warranty if they cause damage to the product. The warranty does not guarantee suitability for any specific application and limits CC's liability for damages.
• Page 30: Returning products for repair involves returning the product to the location where it was purchased or following specific instructions. Additional compliance documentation is available on the company's website.