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Application Guide 

Delta Network Thermostat: BACstat III 

DNT-T221-FCU 

Document Edition 1.3 

 

Product Description 

The DNT-T221-FCU is a packaged product consisting of a DNT-T221 
and an FCM relay module, designed for use with a multi or variable 
speed Fan Coil units. The product makes use of the relay board and the 
DNT’s analog output in order to control the fan. 

The DNT-T221 is an intelligent room thermostat with a custom 3-value, 
96 segment, LCD display. The DNT communicates directly on a 
BACnet MS/TP network. It is capable of displaying a wide-range of 
digital or analog values, including setpoints, temperature, heating and 
cooling status, fan speed, valve position and more. 

When connected on a BACnet MS/TP network the DNT-T221-FCU 
functions as an independent BACnet thermostat.  The firmware can be 
flash loaded over the network, and have jumper selectable termination 
resistors. 

The DNT-T221 has 3 inputs, 2 analog outputs, 1 binary output and a 
built-in Fan Coil application control strategy. As a result, this BACstat is 
capable of stand-alone control when directly connected on an MS/TP 
network. 

 

Contents 

 

Application Guide ........................................................................... 1

 

Contents ....................................................................................... 1

 

Important Information ................................................................... 2

 

Setup & Configuration .................................................................. 3

 

Software & Programming ........................................................... 10

 

Control Functions ....................................................................... 14

 

Output Functions & Types .......................................................... 22

 

OWS Functions .......................................................................... 25

 

Appendix A: Programming Notes ............................................... 28

 

Appendix B: Two Pipe Fan Coil Configuration ........................... 29

 

Appendix C: Four Pipe Fan Coil Configuration .......................... 30

 

Содержание BACstat III DNT-T221-FCU

Страница 1: ...s temperature heating and cooling status fan speed valve position and more When connected on a BACnet MS TP network the DNT T221 FCU functions as an independent BACnet thermostat The firmware can be f...

Страница 2: ...nt from ORCAview System Controllers and Application Controllers certain BACstat capabilities require support from the other products The firmware for the DNT T221 can be flash loaded over the network...

Страница 3: ...figuration Menu is protected by an access code or PIN You must enter the valid PIN before access is granted First press and hold the Up Arrow and then the Down Arrow Hold them both down for at least 5...

Страница 4: ...f Variable Speed fan toggle Auto Adjust Off Bottom Left Down Represents a value of 0 when entering the PIN access code Rotates downward through menu items and options Decreases a numeric value by one...

Страница 5: ...F Settings Additional control settings which are particularly useful when an Application is selected for local control Typically includes Day Setpoint AV6 Max Day Setpoint AV8 Day Differential AV9 CO...

Страница 6: ...bles all access to Service Tool Mode 1 Provides limited access for VAV or full access for other applications 2 Full access with advanced Air Balancer functions for VAV Not for FCU applications 3 Scree...

Страница 7: ...al Fan Screen 1 The Manual Fan screen is accessed by pressing ON 2 Return to the normal screen by pressing OFF or wait for the 30 second timeout Menu Item Description Adjustable fan speed from 0 100 t...

Страница 8: ...AI3 as compared to an external measuring device Navigate past the inputs you don t wish or need to calibrate To manually command AV1 to AV3 0 100 for tri state or PWM and Off or On for binary outputs...

Страница 9: ...nverted to a 0 100 value FT min Contact closure inhibits FCU operation Configuration jumper set to Bin 10K FT sec Contact open inhibits FCU operation Configuration jumper set to Bin 10K 3 C F Standard...

Страница 10: ...71 30 AV7 Day Minimum Minimum Adjustable Day Setpoint C 18 F 65 20 AV8 Day Maximum Maximum Adjustable Day Setpoint C 25 F 77 55 AV9 Day Differential Room Setpoint Differential C 0 5 F 1 2 5 AV10 Nigh...

Страница 11: ...ed Never command the Configuration Variables AV12 AV21 AV22 AV23 on the fly System Events and Statistics System Stats AV34 The Description field in this object provides a count of notable events which...

Страница 12: ...w many items are in the log Code Description H01 EEPROM communication failure H02 RTC communication failure H03 LCD communication failure H04 Reset H05 Flash programming H06 Flash failure H07 Input fa...

Страница 13: ...he BACstat for local operation both display button handling and local control and then write any necessary GCL in another controller for additional strategies For example Through the Configuration Men...

Страница 14: ...orithm Mode The application control strategy operates in one of the following basic modes as determined by the Algorithm Mode variable AV13 Algorithm Mode Description AV13 Unoccupied Night Uses Night...

Страница 15: ...20 1 0 Resets per hour Day Differential AV9 1 0 F 0 5 C Degrees F or C as configured for AI1 Controller Operation Heating Setpoint 100 Cooling Heating Day Setpoint Cooling Setpoint Day Differential De...

Страница 16: ...ion to the value of the reset rate and the magnitude of the error in an attempt to remove the error In this way the Controller Status value is continually fluctuating in order to reach setpoint The am...

Страница 17: ...s Day Heating Setpoint Internal This is the setpoint used internally for heating control which is the Day Setpoint Day Differential This value is not directly adjustable It can only be adjusted by set...

Страница 18: ...Buttons or remote command via GCL or OWS Notes 1 The output functions and types that are available are dependent on the control mode selected and what was selected for the previous output 2 This is no...

Страница 19: ...Interlock Yes Temp Sensor Opt Optional OAT Multi or variable speed fan Heat cool valve HC4P Heat Cool mode Room Temp Interlock Yes Temp Sensor Opt Optional OAT Multi or variable speed fan Cooling 1 C...

Страница 20: ...2 Optional Auto Switch Over Temperature Output 2 is connected to the FCM The FCM steers this signal to the Cooling Valve terminal The DNT T221 FCU provides the controlling signal to the valve This val...

Страница 21: ...dulate under the current mode of operation The mode AV24 is selected automatically based on space conditions Standard Fan Coil Control Heat Only or Cool Only The fan will operate according to the sele...

Страница 22: ...gorithm can determine how to control the output 180 Output 2 is connected to normally closed heating and cooling valves 170 Output 3 is connected to a relay in order to changeover the heating and cool...

Страница 23: ...e proper sequence The configuration code for an output is a combination of its function and type according to the following formula Output Configuration Code Output Function Code Output Type Code For...

Страница 24: ...an Type Occupied Mode Unoccupied Mode Manual Fan Fan On and Off and Speed controlled by user button presses Low speed when the Controller is not in deadband for night setback Off otherwise Multi speed...

Страница 25: ...are It can also be configured using the ORCAview OWS if the BACstat is connected to an MS TP network However to do this it requires a preliminary configuration for each device to ensure they are all c...

Страница 26: ...manual mode and the units are properly set for the sensor Copying the Configuration from One Device to Another It is possible to copy the configuration setup of one DNT T221 FCU to another It is a sim...

Страница 27: ...loading a BACstat file which you have previously saved into a BACstat and in so doing will configure it with the settings contained in the file You can reload the file either back into the source BACs...

Страница 28: ...rrays or command hierarchy Whatever commands the object last is the value the object will have Therefore write your GCL programs so as to minimize any conflicts with acceptable user commands such as t...

Страница 29: ...EAT STG 2 COOL STG 2 INTERLOCK INPUT CLOSE TO STOP SUBLAN OR LINKNET DISCHARGE HWR AIR RETURN AIR CHWR CHWS H C COIL FCM HWS H M L STG2 77 0 elta HTG OFF ON OPTIONAL FCM DEVICE TERMINATION FAN LOW SPE...

Страница 30: ...SHIELDED JACKETED TWISTED PAIR 18 22GA 24 GND IP2 NET GND IP3 BO3 AO2 AO1 BAC ID IN USE BY BAC ID IN USE BY XXX AI1 XXX AI3 XXX AI2 SPACE TEMPERATURE INTERNAL SUPPLY AIR TEMPERATURE XXX AO1 XXX AO2 X...

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