BACnet PTEC Controller Dual Duct 2 AVS - Constant Volume One Inlet and One Outlet Sensor with Optional Reheat, Application 6666 Application Note 140-1114 2014-09-03 Building Technologies
Table of Contents Overview ............................................................................................................................. 5 BACnet .............................................................................................................................. 6 Hardware Inputs .................................................................................................................. 7 Room Unit Identification ...............................................................
Fail Mode Operation .......................................................................................................... 21 Application Notes ............................................................................................................... 22 Wiring Diagrams ................................................................................................................ 22 Application 6666 Point Database ...................................................................................
Overview BACnet Overview NOTE: For information on applications with Firmware Revision Bx40 or earlier, see InfoLink and/or Asset Portal for documentation. In Application 6666, the controller provides independent control of the hot duct and the cold duct inlet dampers to provide a constant volume of air to the space during occupied periods and a lower constant volume of air during unoccupied periods.
Overview BACnet Application 6666 Control Schedule. NOTES: 1. See Control Temperature Setpoints. 2. See Heating/Cooling Switchover. 3. If reheat is not used, this application operates only in cooling mode. 4. The reheat can either be a 2-position valve, hot water valve or time modulated electric reheat. See Optional Auxiliary Heat. 5. This application supports two total volume setpoints; one for occupied periods and on for unoccupied periods. See Control Volume Setpoints. 6.
Overview Hardware Inputs Hardware Inputs Analog Air velocity sensor (two required) Room temperature sensor Room temperature setpoint dial (optional) Auxiliary temperature sensor (optional) Analog sensor (0-10Vdc/4-20 mA) (two) (optional) Digital Unoccupied mode override (optional) Wall switch (optional) Spare digital sensor (optional) NOTE: Digital Room Units (Firmware Revision 26 and later) will update their controlled inputs without putting them Out Of Service.
Overview Ordering Notes Ordering Notes 550-497PA Siemens BACnet PTEC Dual Duct 2 AVS Controller 8 Siemens Industry, Inc.
Sequence of Operation Control Volume Setpoints Sequence of Operation The following paragraphs present the sequence of operation for Application 6666 -One Inlet and One Outlet Sensor with Optional Reheat. NOTE: The controller first meets the volume setpoint requirement of the space and then it controls to the room temperature setpoint requirement. The controller satisfies the airflow requirement of the dual duct even if doing so causes the temperature of the space to drift from its temperature setpoint.
Sequence of Operation Control Temperature Setpoints Control Temperature Setpoints NOTE: Constant Volume Dual Duct applications use OCC.UNOCC and UNOCC OVRD in place of DAY.NGT and NGT OVRD. In addition, these applications use setpoints OCC CLG STPT, OCC HTG STPT, UOC CLG STPT and UOC HTG STPT for the temperature setpoints. This application has a number of different room temperature setpoints (DAY HTG STPT, NGT CLG STPT, RM STPT DIAL, etc.). The application actually controls using the CTL STPT.
Sequence of Operation Control Temperature Setpoints CTL STPT Using Standard/Absolute Mode (Digital Room Unit, Revision 26 and later) Digital Room Unit (2200/2300 Series Firmware Revision 26 and later) For all new digital room units, the value displayed and reported by the room unit is linked to the current heat/cool mode. When the mode changes, the value is automatically updated based on the new heat/cool mode.
Sequence of Operation Control Temperature Setpoints CTL STPT Using Standard/Absolute Mode (Analog or Digital Room Unit) Analog (Series 1000) or Digital Room Units (Firmware Revision 25 or earlier) NOTE: 2200/2300 digital room units with Firmware Revision 25 or earlier are only compatible with standard room unit functionality (no warmer/cooler). When STPT SPAN is set to 0, CLT STPT is set based on the value of the setpoint dial and the setpoint deadband.
Sequence of Operation Heating/Cooling Switchover The full range of the analog room unit slider will be mapped to a range of minimum setpoint value to maximum setpoint value. CTL STPT is set equal to RM STPT DIAL. The values for RM STPT MIN and RM STPT MAX will be applied to limit RM STPT DIAL before it is copied into CTL STPT. Example in Cooling Mode If the STPT SPAN is set to 2.0 degrees, and the DAY CLG STPT is 76°F, the room unit slider will adjust the cooling setpoint from 74°F to 78°F.
Sequence of Operation Heating/Cooling Switchover When the controller is in heating mode, the cooling switchover setpoint is as follows: Cooling switchover point is equal to RM STPT DIAL – DAY HTG STPT + DAY CLG STPT Example DAY CLG STPT = 74 and DAY HTG STPT = 70 In cooling mode, when the user adjusts the setpoint value on the room unit to 76, the heating switchover point will equal 72 - SWITCH DBAND.
Sequence of Operation Room Temperature, Room Temperature Offset and CTL TEMP When the controller is in heating mode, the cooling switchover setpoint is as follows: Cooling switchover point is equal to RM STPT DIAL + 0.5 * the deadband Heating/Cooling Switchover Using Warmer/Cooler Mode (Analog Room Unit) Analog Room Unit (Series 1000) The RM STPT DIAL will display the current temperature setpoint based on a plus or minus position or increment entered by the user at the room unit.
Sequence of Operation Ventilation Demand Minimum Ventilation Demand Minimum This VAV application has the ability to adjust the minimum flow setpoint for varying ventilation needs during occupied times. This may be done internally on controllers with PPCL, or externally via IAQ or DCV programs in a field panel.
Sequence of Operation Control Loops Control Loops The dual duct is controlled by four Proportional, Integral, and Derivative (PID) control loops: two temperature loops and two flow loops. Temperature Loops – The two temperature loops are a cooling loop and a heating loop. The active temperature loop maintains CTL STPT. See Control Temperature Setpoints.
Sequence of Operation Heating Operation The following two situations could occur in cooling mode. However, they are most likely to occur in occupied periods. 1. When the cooling load is light, the cooling loop calls for the cold duct to provide very little air. To maintain a constant volume from the dual duct box, the majority of the air volume from the dual duct box must come from the hot duct.
Sequence of Operation Calibration is in cooling mode, the electric heat is OFF at all times. STAGE COUNT must be set equal to the number of stages of electric reheat being used.
Sequence of Operation Room Unit Operation Floating Control Actuation Auto-correct In addition to the existing options for floating control actuator full stroke actions, all floating control actuators are provided with additional logic to fully drive open or closed when commanded to 100% or 0%. Room Unit Operation Sensor Select SENSOR SEL is a configurable, enumerated point (values are additive). This point tells the controller what type of room unit is being used and how to handle loss of data.
Sequence of Operation Auto Discovery Room CO2 RM CO2 displays the CO2 value in units of parts-per-million (PPM). RM CO2 (from the digital 2200/2300 room units) can be used with PPCL in the PTEC controller or unbundled for control or monitoring purposes. Room RH RM RH displays the relative humidity value in percent. RM RH can be used for PPCL in the PTEC or unbundled for control or monitoring purposes.
Sequence of Operation Application Notes Application Notes If the temperature swings in the room are excessive or there is trouble maintaining the setpoint, then either the cooling loop, the heating loop, or both need to be tuned. If CLG FLOW is oscillating while CLG FLOW STPT is constant, then the flow loop requires tuning. If HTG FLOW is oscillating while HTG FLO STPT is constant, the heating flow loop requires tuning. The controller as shipped from the factory keeps all associated equipment OFF.
Sequence of Operation Wiring Diagrams NOTE: If the voltage/current switch is set to current and a 4 to 20 mA sensor is connected to an AI, then special wiring requirements must be followed. 23 Siemens Industry, Inc.
Sequence of Operation Wiring Diagrams Applications 6665, 6666, 6667, and 6668 with Hot Water Reheat. 24 Siemens Industry, Inc.
Sequence of Operation Wiring Diagrams Applications 6665, 6666, 6667, and 6668 with Electric Auxiliary Reheat. 25 Siemens Industry, Inc.
Application 6666 Point Database Application 6666 Point Database Object Type a) Object Instance (Point Number) Object Name (Descriptor) Factory Default (SI Units) b) Eng Units (SI Units) Range Active Text Inactive Text AO 1 CTLR ADDRESS 255 -- 0-255 -- -- AO 2 APPLICATION 6693 -- 0-32767 -- -- AI {04} ROOM TEMP 74.0 (23.44888) DEG F (DEG C) 48-111.75 -- -- BO {05} HEAT.COOL COOL -- Binary HEAT COOL AO 6 OCC CLG STPT 74.0 (23.44888) DEG F (DEG C) 48-111.
Application 6666 Point Database Object Type a) Object Instance (Point Number) Object Name (Descriptor) Factory Default (SI Units) b) Eng Units (SI Units) Range Active Text Inactive Text AO 36 CLG FLO COEF 1 -- 0-2.
Application 6666 Point Database Object Type a) Object Instance (Point Number) Object Name (Descriptor) Factory Default (SI Units) b) Eng Units (SI Units) Range Active Text Inactive Text AO 72 CLGFLO IGAIN 0.018 -- 0-1.023 -- -- AO 73 CLGFLO DGAIN 0 -- 0-510 -- -- AO {74} HTG FLOW 0 PCT 0-1023.75 -- -- AO {75} CLG FLOW 0 PCT 0-1023.75 -- -- AO {77} VENT DMD MIN 0 (0.0) CFM ( LPS) 0-131068 -- -- AO {78} CTL TEMP 74.0 (23.44888) DEG F (DEG C) 48-111.
Application 6666 Point Database Object Type a) Object Instance (Point Number) Object Name (Descriptor) Factory Default (SI Units) b) Eng Units (SI Units) Range Active Text Inactive Text BI {109} DI 5 OFF -- Binary ON OFF BI {110} DI 6 OFF -- Binary ON OFF AO 111 STPT SPAN 0.0 (0.0) DEG F (DEG C) 0-63.
Issued by Siemens Industry, Inc. Building Technologies Division 1000 Deerfield Pkwy Buffalo Grove IL 60089 Tel. +1 847-215-1000 Document ID 140-1114 Edition 2014-09-03 © 2014 Copyright Siemens Industry, Inc. Technical specifications and availability subject to change without notice.
