TEC Controller Unit Conditioner - VAV Pressure Dependent with Hot Water Heat, Application 2041 Application Note 140-1130 2014-05-01 Building Technologies
Table of Contents Overview ............................................................................................................................. 4 Hardware Inputs .................................................................................................................. 5 Hardware Outputs ................................................................................................................ 5 Ordering Notes .............................................................................
Overview Hardware Inputs Overview In Application 2041, the controller modulates the supply air damper of the terminal box for cooling and modulates a reheat valve(s) for heating. When in heating, minimum airflow (limited by a mechanical stop on the terminal box) is provided to the room. In order for the terminal box to work properly, the central air-handling unit must provide cool supply air. Application 2041 - VAV Pressure Dependent with Hot Water Reheat Control Diagram.
Overview Hardware Inputs NOTES: 1. See Control Temperature Setpoints. 2. See Heating/Cooling Switchover. 3. The reheat valve is modulated. 4. The airflow is shown at minimum in the entire heating mode.
Sequence of Operation Control Temperature Setpoints Sequence of Operation The following paragraphs present the sequence of operation for the Siemens TEC Unit Conditioner (Fan Coil) Controller. Control 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 Room Temperature and CTL TEMP CTL STPT is calculated as follows: With Deadband Disabled: CTL STPT = Dial value With Deadband enabled in Heat Mode: CTL STPT = Dial value – 0.5 ∗ Deadband (limited between the value of RM STPT MIN and RM STPT MAX) With Deadband enabled in Cool Mode: CTL STPT = Dial value + 0.5 ∗ Deadband (limited between the value of RM STPT MIN and RM STPT MAX). NOTE: If RM STPT DIAL is failed, it maintains the last known value.
Sequence of Operation Day and Night Modes Day and Night Modes The day/night status of the space is determined by the status of DAY.NGT. The control of this point differs depending on whether the controller is monitoring the status of a wall switch or if the controller is connected to a field panel. When a wall switch is physically connected to the termination strip on the controller DI 2 (see the Control Diagram(s), and WALL SWITCH = YES, the controller monitors the status of DI 2.
Sequence of Operation Control Loops Control Loops The Siemens TEC Unit Conditioner (Fan Coil) Controller is controlled by two Proportional, Integral, and Derivative (PID) temperature loops. The two temperature loops are a cooling loop and a heating loop. The active temperature loop maintains room temperature at the value in CTL STPT. See Control Temperature Setpoints [➙ 6]. Cooling Operation In cooling mode, the controller uses CTL STPT and CTL TEMP as inputs for the cooling loop.
Sequence of Operation Sequencing Logic (Optional) NOTE: If a valve’s start and end point values are set to the same value, the valve will not be used. Sequencing Logic (Optional) In heating mode, this application includes logic that allows two heating valves to operate in sequence, parallel, or overlapping. This algorithm is very similar to the spring range sequencing of valves and dampers. Portions of the output of the heating loop, HTG LOOPOUT, will drive the two heating valves from 0 to 100%.
Sequence of Operation Calibration When HTG LOOPOUT = 25%, VLV 1 COMD will equal 50% open and VLV 2 COMD will equal 0% open. When HTG LOOPOUT = 50%, VLV 1 COMD will equal 100% open and VLV 2 COMD will equal 0% open. When HTG LOOPOUT = 75%, VLV 1 COMD will equal 100% open and VLV 2 COMD will equal 50% open. When HTG LOOPOUT = 100%, VLV 1 COMD will equal 100% open and VLV 2 COMD will equal 100% open. Example 2 Assume that your system has two hot water valves that are to operate in parallel.
Sequence of Operation Fail Mode Operation The calibration consists of driving the valve(s) closed, and then resetting the value of VLV 1 POS to 0. If a second valve is used, VLV 2 POS is also set to 0. The actuators are then released to normal control. 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%.
Sequence of Operation Wiring Diagram Wiring Diagram CAUTION The controller’s DOs control 24 Vac loads only. The maximum rating is 12 VA for each DO.
Application 2041 Point Database Application 2041 Point Database Point Number Descriptor Factory Default (SI Units)2) Eng Units (SI Units) Slope (SI Units) Intercept (SI Units) On Text Off Text 1 CTLR ADDRESS 99 -- 1 0 -- -- 2 APPLICATION 2090 -- 1 0 -- -- {04} ROOM TEMP 74.0 (23.44888) DEG F (DEG C) 0.25 (0.14) 48.0 (8.88888) -- -- {05} HEAT.COOL COOL -- -- -- HEAT COOL 6 DAY CLG STPT 74.0 (23.44888) DEG F (DEG C) 0.25 (0.14) 48.0 (8.
Application 2041 Point Database Point Number Descriptor Factory Default (SI Units)2) Eng Units (SI Units) Slope (SI Units) Intercept (SI Units) On Text Off Text {42} DO 2 OFF -- -- -- ON OFF {43} DO 3 OFF -- -- -- ON OFF {44} DO 4 OFF -- -- -- ON OFF {45} DO 5 OFF -- -- -- ON OFF {46} DO 6 OFF -- -- -- ON OFF {48} DMPR COMD 0 PCT 0.4 0 -- -- {49} DMPR POS 0 PCT 0.4 0 -- -- 51 MTR 1 TIMING 130 SEC 1 0 -- -- {52} VLV 1 COMD 0 PCT 0.
Application 2041 Point Database Point Number Descriptor Factory Default (SI Units)2) Eng Units (SI Units) Slope (SI Units) Intercept (SI Units) On Text Off Text {99} ERROR STATUS 0 -- 1 0 -- -- 1) Points not listed are not used in this application. 2) A single value in a column means that the value is the same in English units and in SI units. 3) Point numbers that appear in brackets { } may be unbundled at the field panel. 16 Siemens Industry, Inc.
Issued by Siemens Industry, Inc. Building Technologies Division 1000 Deerfield Pkwy Buffalo Grove IL 60089 Tel. +1 847-215-1000 Document ID 140-1130 Edition 2014-05-01 © 2014 Copyright Siemens Industry, Inc. Technical specifications and availability subject to change without notice.
