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IM 1234-1 • BACNET THERMOSTAT 28 www.DaikinApplied.com

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PID Control Loops

A PID control loop calculates an error value from the difference 

between the measured room temperature and the active 

setpoint. The error value is expressed as a percentage and 

is typically used in a BAS controller to control the state of an 

output. When the difference between the setpoint and room 

temperature is large, the error is large. As the system reduces 

the difference between the setpoint and space temperature, 

the error becomes smaller. In a simple example, if the output 

of the PID loop that is controlling a modulating valve is 50% 

the valve would be opened half way; if the output of the loop is 

100% the valve position is fully open.
The BACnet Thermostat heating and cooling PID loops are 

implemented in all models.
The BACnet Thermostat uses a PID loop for the discharge 

air temperature. The discharge air loop controls the position 

of the economizer. For this loop the setpoint is the measured 

temperature of the air that is discharged by a roof top or heat 

pump unit.
The PID loops in the BACnet Thermostat are standard BACnet 

objects.

Valve Operation for Fan Coil Units

Hot and chilled water valves are used for heating and cooling 

in the fan coil unit version of the BACnet Thermostat. The 

two-pipe programming includes a method to determine supply 

water temperature.

ON/OFF Valves

On a call for cooling or heating, the valve will open once the 

loop controlling the valve has reached 50%. The valve will 

close once the loop has fallen to 5%.

• 

Normal

 – The valve is closed when the output is inactive 

and open when the output is active

• 

Reverse

 – The valve is closed when the output is active 

and open when the output is inactive

Modulating Valves

On a call for cooling or heating, a modulating valve will 

modulate from 0 to 100% over the first half (0 to 50%) of the 

PID loop output controlling the valve. The BACnet Thermostat 

supports both normal and reverse action which can be set from 

the user interface.

• 

Normal 

– The valve is fully closed when the output signal 

is 0 volts and fully open when the output is 10 volts DC

• 

Reverse

 – The valve is fully closed when the output signal 

is 10 volts and fully open when the output is 0 volts DC

Two-Pipe Water Supply Temperature 

Evaluation

For two-pipe fan coil units, the BACnet Thermostat uses the 

water supply temperature sensor, input WST, to determine if 

chilled or hot water is being supplied to the unit. The water type 

is determined by comparing the value of the water temperature 

sensor input to the room temperature. The BACnet Thermostat 

programming then determines that the water temperature is 

one of the following.

• 

Chilled

 – the water temperature is 10°F below room 

temperature

• 

Hot

 – the water temperature is 10°F above room 

temperature

• 

None

 – the water temperature is within 7°F of room 

temperature

If the water temperature is evaluated as None, the BACnet 

Thermostat runs the water evaluation program every six hours. 

During a water evaluation, the BACnet Thermostat opens 

the valve until a water type is determined or for five minutes, 

whichever is reached first. If a water evaluation is not being 

performed, the valve remains closed.
The supply water type is stored in multistate variable 

Water 

Available

.

Fan Operation for Fan Coil Units

The BACnet Thermostat has two parts to fan operation.

•  Automatic fan control can be controlled from the user 

interface by a user with Password 1

•  Fan speed is set up during commissioning by a user with 

Password 2

Automatic Fan Control

A user with Password 1 can set the BACnet Thermostat 

controlled fan to either run continuously or to start 

automatically on a call for cooling or heating.

Auto

 – When Auto is selected, the fan runs only when there is 

a call for cooling or heating. It continues to run after the call for 

cooling or heating for the period set by the fan delay timer.

ON

 – The fan will run continuously regardless of the heat/cool 

modes or occupied state.

Low, Medium, High

 – For systems with three-speed fans, 

the user has the choice of low, medium or high speed as the 

continuous running speed.

Содержание BACnet IM 1234-1

Страница 1: ...Installation and Maintenance Manual IM 1234 1 Group Applied Air Systems Part Number IM 1234 Date December 2014 BACnet Thermostat Use with Daikin MicroTech Integrated Systems or as standalone ...

Страница 2: ...s 10 Commissioning Functions 14 Set Up Communications 16 Set the Time and Date 17 Setting the Occupancy Schedule 18 Set Fan Coil Unit System Options 19 Set Rooftop Unit System Options 21 Set Heat Pump Unit Systems Options 23 Advanced Options 25 Sequences of Operation 27 Room Temperature Setpoints 27 Occupancy 27 Automatic Cooling and Heating Changeover 27 Schedules 27 PID Control Loops 28 Valve Op...

Страница 3: ...ive BACnet Application Specific Controllers BACnet communication parameters device instance MAC address baud rate user adjustments and application configuration values are set from password protected front panel controls All models feature an integrated BACnet schedule and hardware real time clock with 72 hour capacitor backup for standalone operation or network time synchronization A two piece me...

Страница 4: ...oads up to 10 mA at 0 12 volts DC 8 bit PWM digital to analog conversion Relay Outputs Relay outputs are configured to represent BACnet binary objects The outputs control ON OFF valves speeds for three speed fans fan start circuits or other equipment that requires an on or off input signal All relay outputs are normally open SPST Form A relays 1 Ampere maximum per relay at 24 volts AC or DC for ea...

Страница 5: ...t Dimensions A B C 3 50 in 89 mm 5 12 in 130 mm 1 12 in 29 mm BACnet Thermostat Product Numbers Description Product Number Model Number Fan Coil Unit 2 pipe and 4 pipe Modulating or ON OFF valves Modulating or Three Speed Fan 2508035 MIT FA 005 Roof Top Unit Modulating or ON OFF valves One or two stages heat One or two stages cooling Fan control Economizer 2508034 MIT RA 007 Heat Pump Unit 3 heat ...

Страница 6: ...ical box or a box with a wall plate kit Routing the connecting cable or cables from the BACnet Thermostat to the equipment it is controlling Block leaks and airflow from conduits with plumber s putty or similar material If replacing an existing thermostat label existing wires for reference when removing the existing thermostat Figure 2 BACnet Thermostat Mounting Base Details Installing the BACnet ...

Страница 7: ... pull up resistor Follow the instructions supplied with the sensor for installation Figure 5 Wiring for Discharge Air Temperature Sensor Fan Status Switch optional Connect a Normally Closed Fan Status switch to the Discharge Air Temperature DAT input and ground GND terminals The input includes the internal pull up resistor Follow the instructions supplied with the switch for installation Figure 6 ...

Страница 8: ... be a 24 volt AC pilot duty only For a single speed fan use only the FAN L connection For a two speed fan use the FAN L and Fan H connections For a three speed use FAN L FAN M and FAN H Figure 9 Connections to a Three Speed Fan Connecting to a Modulating Fan The following diagram shows the connections for a modulating speed fan The fan start circuit must be a 24 volt AC circuit Connect it to the F...

Страница 9: ...e size to supply power Daikin Applied recommends powering the BACnet Thermostat from a dedicated controls transformer Connect the transformer s neutral lead to the COM terminal Connect the AC phase lead to the 24VAC terminal Power is applied to the controller when the transformer is powered Figure 13 Wiring for BACnet Thermostat Power Maintenance Remove dust as necessary from the holes in the top ...

Страница 10: ... to the previous menu Cncl Cancels current changes Done Push this button at any point while entering a value For example if you have entered the first two digits of a password and the remaining two digits are correct pushing Done completes the entry of the password Enter Pushing this button enters the selection and advances to the next step Exit Returns to temperature display The operating modes o...

Страница 11: ...ance to the first menu Changing the Active Setpoints To enter or change the active temperature setpoints you may need to enter a user password NOTE In the following procedure the current active setpoint either cooling or heating is the first setpoint to change Once that setpoint is entered the display advances to the next setpoint Table 4 Changing the Active Setpoints Procedure Steps Display Start...

Страница 12: ...g in a heat pump unit Heat The system will only heat the space Cool The system will only cool the space Auto The system will switch between heating and cooling Off The system is turned OFF 3 Press the Enter button to save the setting The display returns to the temperature display Heating cooling icons Set the fan mode 1 Push the button under the fan icon NOTE If a user password has previously been...

Страница 13: ...ss the Enter button to select the next digit of the password 4 Press either the or button to turn the override ON or OFF Override Off The controller uses the unoccupied setpoint as the active setpoint Override On The controller changes to the occupied setpoint which can then be temporarily changed 5 Press the Enter button to save the setting NOTE When the system is in the unoccupied mode changing ...

Страница 14: ...ommissioning functions cover all of the functions that can be set in the controller Not all functions are available on every model of controller Enter the Commissioning Mode For access to the commissioning functions you will need to know Password 2 If the controller has not been previously set up no password is required A new Password 2 can be entered in the advanced commissioning functions Table ...

Страница 15: ...ess either the or button to select SETPOINT 2 Press Enter The SETPOINT menu opens 3 Choose and set each of the following setpoints OCC COOL The cooling setpoint that is used as the active setpoint when the system is occupied OCC HEAT The heating setpoint that is used as the active setpoint when the system is occupied UNOCC COOL The cooling setpoint that is used as the active setpoint when the syst...

Страница 16: ...u display Change the network communication properties 1 From the MAIN menu press either the or button to select COMM 2 Press Enter The COMM menu opens up 3 Choose and set the following properties DEVICE ID This is the BACnet device instance The device instance must be within the range of 1 to 4 194 302 MAC The MAC address must be in the range of 1 127 BAUD Set to match other devices on the BACnet ...

Страница 17: ... Press Enter The SCHEDULE menu opens 3 Choose SET CLOCK and then press Enter The SET CLOCK menu opens Choose a clock function to set Choose one of the features in the SET CLOCK menu to change the date time or Daylight Saving Time DST setting DATE The current calendar date TIME Time is set according to a 12 hour clock DST ENABLE Set to TRUE to enable Daylight Saving Time and FALSE to use standard t...

Страница 18: ...EKDAYS Sets the schedule for Monday to Friday Saturday and Sunday are not changed WEEKEND Sets the schedule for Saturday and Sunday Monday to Friday remain unchanged INDIVIDUAL DAYS Sets the schedule for just the selected day of the week 2 Change the daily times and values in the schedule to set the occupancy mode to either ON or OFF When finished with each pair push Enter or Done When finished wi...

Страница 19: ...ermostat will hold an override temperature setpoint as the active setpoint At the end of the period the BACnet Thermostat will use either an occupied or unoccupied setpoint as the active setpoint Set the fan delay From the SYSTEM menu choose FAN DELAY OFF to set the time the system fan will continue to run after the last heating or cooling stage is turned OFF Set the occupied fan control From the ...

Страница 20: ... will run when a user sets the fan speed to LOW FAN MAXIMUM Sets the fastest speed at which the fan will run when a user sets the fan speed to HIGH The MED speed is automatically set halfway between the LOW and HIGH settings Set fan speeds for three speed fans Select FAN SPEEDS from the SYSTEM menu to designate the number of speeds at which the installed fan will run Enable auxiliary heat Choose A...

Страница 21: ...he BACnet Thermostat will hold an override temperature setpoint as the active setpoint At the end of the period the BACnet Thermostat will use either an occupied or unoccupied setpoint as the active setpoint Set the fan delay From the SYSTEM menu choose FAN DELAY OFF to set the time the system fan will continue to run after the last heating or cooling stage is turned OFF Set the occupied fan contr...

Страница 22: ...N ENABLE TEM Enter the value that the outside air temperature must fall below before the economizer damper can open 4 From the SYSTEM menu choose MIN DAT Enter the minimum discharge air temperature that will be allowed during cooling when the economizer is enabled Set heating fan control From the SYSTEM menu choose HEATING FAN and then choose one for the following AUTO The fan runs only on a call ...

Страница 23: ...oose LOCAL OVRD TIME to set the time the BACnet Thermostat will hold an override temperature setpoint as the active setpoint At the end of the period the BACnet Thermostat will use either an occupied or unoccupied setpoint as the active setpoint Set the fan delay From the SYSTEM menu choose FAN DELAY OFF to set the time the system fan will continue to run after the last heating or cooling stage is...

Страница 24: ...f the polarity settings Active Heating The O B output terminal is active on a call for heating Active Cooling The O B output terminal is active on a call for cooling Set up auxiliary heat Optional feature From the SYSTEM menu choose AUX HEAT Comp Lockout The BACnet Thermostat will enable auxiliary heat only when the compressors are locked out because of low outside air temperature 3rd Stage The BA...

Страница 25: ...plication program in every BACnet Thermostat The Metric version displays temperature in Celsius and uses metric values for units of measure The English version displays temperature in Fahrenheit and uses English values for units of measure NOTE Choosing an application will reset the BACnet Thermostat Adjust the PID loops Choose LOOPS from the ADVANCED menu to adjust the values for the cooling or h...

Страница 26: ...y appearance after the last button is pushed BLANKING Choose one of the blanking options CLOCK An analog clock replaces the temperature and mode icons BACKLIGHT OFF The display brightness changes to the level set by DIM LEVEL after the last button interaction NONE The temperature and mode icons always remain visible DIM LEVEL Sets the level of brightness of the display back light if BACKLIGHT OFF ...

Страница 27: ...trolled by the schedule in the controller Setpoint Limits No cooling setpoint can be higher than any heating setpoint If a user is adjusting a setpoint and it comes with the range set by Minimum Setpoint Differential the corresponding setpoint will be changed to maintain the differential For example the Minimum Setpoint Differential is 4 F and the Occupied Heating setpoint is 70 F If the user lowe...

Страница 28: ...rmal and reverse action which can be set from the user interface Normal The valve is fully closed when the output signal is 0 volts and fully open when the output is 10 volts DC Reverse The valve is fully closed when the output signal is 10 volts and fully open when the output is 0 volts DC Two Pipe Water Supply Temperature Evaluation For two pipe fan coil units the BACnet Thermostat uses the wate...

Страница 29: ...anges from 0 to 100 When the heating loop returns to 0 heating stops until the loop reaches 100 again Valve Action The BACnet Thermostat supports both normal and reverse valve action that can be set from the user interface Normal The valve is fully closed when the output signal is 0 volts and fully open when the output is 10 volts DC Reverse The valve is fully closed when the output signal is 10 v...

Страница 30: ...re loop modulates from 0 to 100 as the Discharge Air Temperature rises above the Discharge Air Temperature setpoint The Discharge Air Temperature setpoint resets between room temperature and the limit for minimum discharge air temperature as the cooling loop varies between 0 and 50 If the Discharge Air Temperature decreases below 55 F the Outside Air Damper returns to the minimum damper position H...

Страница 31: ... with Three Speed Fan and ON OFF Valves Fan status switch FST and discharge air temperature sensor DAT are optional They are typically used only when the BACnet Thermostat is connected to a network The remote temperature sensor is optional Valves are for 24 volt AC pilot duty inputs Fan outputs are for 24 volt AC pilot duty inputs For additional details on connecting sensors see Connecting Inputs ...

Страница 32: ...e BACnet Thermostat is connected to a network The remote temperature sensor RS is optional Valves are 24 volt AC with a 0 10 volt DC control signal Fan outputs are for 24 volt AC pilot duty inputs For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs on page 8 Figure 16 Fan Coil Unit Wiring Detail...

Страница 33: ...n the BACnet Thermostat is connected to a network The remote temperature sensor RS is optional Valves are 24 Volt DC Fan starting input is 24 volt AC pilot duty Fan speed input is 0 10 volts DC For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs on page 8 Figure 17 Fan Coil Unit Wiring Details F...

Страница 34: ... BACnet Thermostat is connected to a network The remote temperature sensor RS is optional Valves are 24 Volt AC Fan start output is for a 24 volt AC pilot duty input Fan speed input is 0 10 volts DC For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs on page 8 Figure 18 Fan Coil Unit Wiring Deta...

Страница 35: ...are optional They are typically used only when the BACnet Thermostat is connected to a network The remote temperature sensor RS is optional The valve is 24 volt AC Fan outputs are for 24 volt AC pilot duty inputs For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs on page 8 Figure 19 Fan Coil Un...

Страница 36: ... are typically used only when the BACnet Thermostat is connected to a network The remote temperature sensor RS is optional Valves are 24 volt AC with a 0 10 volt DC control signal Fan outputs are for 24 volt AC pilot duty inputs For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs on page 8 Figur...

Страница 37: ...pically used only when the BACnet Thermostat is connected to a network The remote temperature sensor RS is optional Valves are 24 Volt AC Fan start output FAN L is for a 24 volt AC pilot duty input Fan speed output AO8 is 0 10 volts DC For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs on page ...

Страница 38: ...pically used only when the BACnet Thermostat is connected to a network The remote temperature sensor RS is optional Valves are 24 Volt AC Fan start output FAN L is for a 24 volt AC pilot duty input Fan speed output AO8 is 0 10 volts DC For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs on page ...

Страница 39: ...ional They are typically used only when the BACnet Thermostat is connected to a network The remote temperature sensor RS is optional For single stage heating do not connect W2 For single stage cooling do not connect Y2 Connect outputs to 24 volt AC pilot duty inputs For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves ...

Страница 40: ...r temperature OAT sensors are required for economizer operation The remote temperature sensor RS is optional For single stage heating do not connect W2 For single stage cooling do not connect Y2 Connect outputs to 24 volt AC pilot duty inputs For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs o...

Страница 41: ... air temperature DAT and outdoor air temperature OAT sensors are required for economizer operation The remote temperature sensor RS is optional Connect heating and fan outputs to 24 volt AC pilot duty inputs For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs on page 8 Figure 25 Roof Top Unit Wi...

Страница 42: ...arge air temperature DAT and outdoor air temperature OAT sensors are required for economizer operation The remote temperature sensor RS is optional Connect the fan output to a 24 volt AC pilot duty input For additional details on connecting sensors see Connecting Inputs on page 7 For additional details on connecting the fan and valves see Connecting Outputs on page 8 Figure 26 Roof Top Unit Wiring...

Страница 43: ...n the BACnet Thermostat is connected to a network The outdoor air temperature sensor OAT is required for compressor lockout based on outside air temperature The remote temperature sensor RS is optional For single compressor installations do not connect Y2 If auxiliary heat is not required do not connect AUX E Connect outputs only to 24 volt AC pilot duty inputs For additional details on connecting...

Страница 44: ...r air temperature sensor OAT is required for compressor lockout based on outside air temperature The remote temperature sensor RS is optional For single compressor installations do not connect Y2 If auxiliary heat is not required do not connect AUX E Connect outputs only to 24 volt AC pilot duty inputs Economizer ECON input is 0 10 volts DC For additional details on connecting sensors see Connecti...

Страница 45: ...munications on page 16 for the procedure to set the following Device Instance MAC address Baud Use the following principles when wiring the BACnet Thermostat to an MS TP network Connect no more than 128 addressable BACnet devices to one MS TP network Use 18 gauge twisted pair shielded cable for all network wiring Connect the A terminal in parallel with all other terminals Connect the B terminal in...

Страница 46: ...ant to its standard terms and conditions of sale including Limited Product Warranty Consult your local Daikin Applied representative for warranty details To find your local Daikin Applied representative go to www DaikinApplied com Aftermarket Services To find your local parts office visit www DaikinApplied com or call 800 37PARTS 800 377 2787 To find your local service office visit www DaikinAppli...

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