ELECTRONIC THERMOSTAT: T920

Transcription

1 μnistδt ELECTRONIC THERMOSTAT: T One analog output DESCRIPTION The T series thermostats are microcomputer-based, proportional and integral (PI) devices with one analog 0 to 0 output. They can be used with most controlled devices in the HVAC industry that are compatible with this signal. A typical application would be to control an analog VAV or valve actuator. The thermostats also contain three dip switch to adjust the following parameters : Room or supply control applications ** Internal or external remote sensor Direct or reverse acting mode ** See REMOTE SENSOR TYPICAL WIRING section for testing procedures when enabling this function. The thermostat also have internally mounted potentiometers that adjusts minimum & maximum voltage. or example, they can be used as minimum position adjustment on a dry bulb economizer type control or as min. & max. airflow adjustment on a pressure dependent VAV box. Type of output Modulating analog 0 to 0 SPECIICATIONS In cooling Modulating devices Analog damper actuator Analog valve actuator In heating Modulating devices Analog damper actuator Analog valve actuator SCR s power controls Operating Conditions: -0 C to C ( - to ) 0% to 9% R.H. non-condensing Sensor: Local 7 K NTC thermistor Resolution: ± 0. C ( ± 0. ) Control accuracy: ± 0. C ( ± 0. ) ( calibrated ) Ranges: 0 C to C ( to ) Night setup for cooling mode ( TN only ): C ( 9 ) night setup Night setback for heating mode ( TN only ): C ( 9 ) night setback DAY-NIGHT MODE ( TN ONLY ) The TN has a day / night input and an override button and night mode led mounted on the thermostat cover. The night mode, initiated by a remote timer or computer contact, provides energy savings during unoccupied periods of up to 0 %, without sacrificing comfort in occupied rooms. A flashing LED indicates that the thermostat is in Night mode. The occupant may override this condition locally for. hours by pressing the button on the thermostat cover. When output is in Cooling mode Heating mode DIMENSIONS WIRING ROM TOP OR ROM BACK SECURITY SCREW HOW TO ORDER T - D = Day C = C scale N = Night = scale Notes: Example: TD-C BASE.7" ( 8 mm ) input activates C (9 ) night setup C (9 ) night setback Order changeover sensors such as S0, S, S and S separately. Vertical covers are standard. without night mode Lexan cover with: C 0." ( mm ).8" ( 7 mm ).7" mm Proportional band for room temperature control ( S = 0 ):.8 C (. ) Proportional band for supply temperature control ( S = ): 8 C ( ) Analog output: Power: 0 to 0 into KΩ resistance min. -%, +0% /0 Hz; VA Issue Date: May 8, R

2 ANALOG 0 TO 0 VDC OUTPUT THERMOSTAT INSTALLATION This output is designed to give true PI modulation out of analog 0 to 0 actuator for VAV dampers and valves. The analog 0 to 0 output feature internal potentiometers for minimum, maximum voltage adjustment:: ( Vmin. & Vmax ). The output is normally cooling but can be reversed to heating mode with different methods: An internal dip switch reverses the output to a fixed heating mode Auto changeover to heating mode with a supply sensor. A remote sensor can be used for each thermostat.( S0 or S or S ) Supply temperature > 78 ( C) = heating mode Supply temperature < 7 ( C) = cooling mode Hysterisys is ( C) Auto changeover to heating mode with a dry contact. A closed contact on the changeover input will change operation of the 0 to 0 output to heating mode. Open contact = cooling mode Closed contact = heating mode Important. Electronic controllers require special care for wiring and startup. To avoid problems, carefully follow the procedures below. Be sure to have all the literature on hand for all components installed: controller, actuators, relay, etc... Look at the wiring diagrams, and study them carefully. Be sure that you understand how the system is supposed to work. Make the wiring according to the wiring diagrams. Respect polarity for power terminals # & # between multiple controllers if the same transformer is used. Remove security screw on left side of thermostat cover. Open up by pulling on the bottom side of thermostat. Characteristics of remote and changeover sensor7 KΩ ( S0, S or S ). Temperature Temperature C Sensor resistance.0. C 9.0 Kohm C.0 Kohm 0.0. C. Kohm C 7.8 Kohm 0.0. C. Kohm C 7. Kohm.0. C.8 Kohm.0.7 C. Kohm.0. C.8 Kohm 0.0. C 7.8 Kohm C 9.0 Kohm 0.0. C.98 Kohm A) Location: - Shouldn t be installed on outside wall. - Must be installed away from any heat source. - Shouldn t be affected by direct sun radiation. - Nothing must restrain vertical air circulation to the thermostat. B) Installation: - Pull out cables out of the wall. - Wall surface must be flat and clean. - Separate the thermostat and the base by pulling the cover by the bottom (same as the security screw.) - Insert cable in the central hole of the base. - Align the base and mark the location of the two mounting holes on the wall. Install proper side of base up. - Install shields in the wall. 7- Insert screws in mounting holes on each side of the base. DO NOT OVERTIGHTEN! 8- Strip each wire / inch. 9- Insert each wire according to wiring diagram. 0- Reinstall the cover ( top side first ) and gently push back extra wire length in the hole in the wall. - Install security screw.

3 DIP SWITCH ADJUSTMENTS PER APPLICATIONS S ON O APPLICATION SWITCH or discharge air or supply temperature control ** or regular room control applications S MAIN TEMPERATURE SENSOR S ON O internal sensor for room temperature sensing Main temperature sensor is remote mounted ** See REMOTE SENSOR TYPICAL WIRING section for testing procedures when enabling this function. CONTROL CURVES AND SEQUENCE CHANGEOVER O ANALOG 0 TO 0 OUTPUT ON Reverses the output to a fixed heating mode (RA) O Output is cooling (DA) Auto changeover of output to heating mode (RA) with a supply sensor or, Auto changeover to heating mode (RA) with a dry contact Opened 00% Device opened 0 or Vmax. SETPOINT DIAL Device opened 0 or Vmax. % Heating mode changeover input active Cooling mode Closed 0% Device closed 0 or Vmin TYPICAL APPLICATIONS Temperature increase Pressure Dependent VAV Dip switch position S S S Cooling only O ON O Analog VAV Actuator 0 Room Temperature Control With Internal Minimum & Maximum Position Adjustments 0 to 0 0 to 0

4 Pressure Dependent VAV With: Cool / Heat Auto Changeover Input Dip switch position S S S Cool / heat auto changeover input O ON O Changeover 0 to 0 Sensor Analog Actuator Supply air temperature sensor 0 0 to 0 Room Temperature Control With Internal Minimum & Maximum Position Adjustments 0 to 0 Mixed Air Control or ree Cooling Dip switch position S S S or dry bulb economizer control ON O O 0 to 0 Analog Actuator Supply Sensor Supply air temperature sensor 0 Supply Temperature Control With Internal Minimum Position Adjustment 0 to 0 0 to 0

5 Valve Control With Room Dip switch position S S S Cooling only O ON O Heating only O ON ON 0 Analog Valve Cooling Room Temperature Control 0 to 0 0 to 0 Analog Valve Heating 0 Room Temperature Control Valve Control With Room With: Cool / Heat Auto Changeover Input Dip switch position S S S Cool / heat auto changeover input O ON O Analog Valve Heating and/or Cooling Optional Water Supply Sensor 0 0 to 0 Room Temperature Control 0 to 0 Supply water temperature sensor

6 VAC POWER AND ANALOG ACTUATOR TYPICAL WIRING Va. 0 to 0 output Va. 0 to 0 input Va. 0 to 0 input Modulating electronic actuator To other Modulating electronic actuator 0 to 0 or to 0 0 to 0 or to 0 Power Supply -% +0% /0 HZ VA Note: terminals,, and can be wired together between each thermostat if polarity is respected Important: if using a common transformer, respect polarity ( and between thermostats and actuator ) REMOTE TEMPERATURE SENSOR TYPICAL WIRING If a remote sensor is used, set dip switch S to position 0 (off). types of remote sensor can be used for different applications.. S0 or S for remote duct sensor applications. S for remote room sensor applications. S for immersion sensor applications When using the thermostat in a supply control or a discharge control application, set dip switch S to position (on). This will enable control parameters for these applications that make temperature control more stable. Special testing procedures when supply control mode is enabled ( S = ).Due to the large value of the proportional bands in this mode 8 C ( ), it will not be possible to bring immediately both output to either 0 or 0 value by turning the dial to full heat or full cold when testing. The PI control loop in this case is designed to give stable supply control with as few movement possible to the end devices. To speed up the testing procedure, it is recommended that both output be tested in the room control mode ( S = 0 ) to confirm that both end devices are operating properly from full open to full close. after the tests are done, reset the switch to supply control mode ( S = ). Remote sensor input OR S0 or S Duct OR S Immersion S Room THERMOSTATS OR ACTUATOR SPECIAL WIRING HIGH SIGNAL SELECTION APPLICATION Va. 0 to 0 output Va. 0 to 0 output Va. 0 to 0 input Modulating electronic actuator 0 to 0 or to 0 In order to work, both thermostats must be set for cooling ( DA ) or heating ( RA ). The resulting signal going to the actuator is the highest cooling or heating demand. This setup is used mostly on heating supply low limit temperature control.

7 CHANGEOVER INPUT TYPICAL WIRING MULTIPLE TRANSORMERS ( DRY CONTACT OR ALL THERMOSTATS ) Open contact = Cooling mode. Closed contact = Heating mode Transformer Primary Transformer Primary Do Not Ground Any Transformer To Earth Changeover Input Changeover Input Cool / Heat Changeover Contact SINGLE TRANSORMER ( DRY CONTACT OR ALL THERMOSTATS ) Open contact = Cooling mode. Closed contact = Heating mode Primary Transformer Changeover Input Changeover Input Cool / Heat Changeover Contact SUPPLY CHANGEOVER SENSOR PER THERMOSTAT ( SUPPLY SENSOR PER THERMOSTAT ) Auto changeover input using an S0, S duct supply sensor or S immersion supply sensor Supply temperature > 78 ( C) = Heating mode Supply temperature < 7 ( C) = Cooling mode Hysterisys is ( C) between heating and cooling Cool / heat automatic changeover input S0 or S Duct OR S Immersion 7

8 INPUT TYPICAL WIRING ( TN ONLY ) MULTIPLE TRANSORMERS Closed = night mode. contact can be used for all thermostats on the same transformer. Transformer Primary Transformer Primary Do Not Ground Any Transformer To Earth Mode Input Mode Input Mode Contact SINGLE TRANSORMER Closed = night mode. contact can be used for all thermostats on the same transformer. Primary Transformer Mode Input Mode Input Mode Contact Viconics Electronics Inc. 9, Langelier Blvd, St-Leonard, Quebec, Canada HP K9 LIT-TX-E0 8