Fume Hood Controller 2-Position Constant Volume with Damper, Application 2940 Application Note Building Technologies 140-1317 2015-11-04 Restricted
Table of Contents Overview ............................................................................................................................. 4 Hardware Inputs .................................................................................................................. 5 Hardware Outputs ................................................................................................................ 5 Ordering Notes .............................................................................
Overview Hardware Inputs Overview Application 2940 is designed for use with a constant volume or two position fume hood in a manifold fume hood exhaust system. In this application, two position fume hoods have an individual exhaust damper connected to a central fan. The application modulates the exhaust damper to maintain a high or low flow set point based on inputs from the ODP (Operators Display Panel), digital Input, an exhaust air flow sensor and the controller setpoints.
Overview Hardware Inputs Hardware Inputs Analog Air velocity sensor(s) – (2nd sensor available for field use) (Optional) Differential pressure transmitter/Linear Flow input (Vortex Shedder) Digital Operator Display Panel (ODP) (Optional) High/Low select (through DI 2) (Optional) Startup Mode (through DI 4) (Optional) Remote Emergency Purge (through DI 6) Hardware Outputs Analog Operator Display Panel (ODP) AO2 (flow signal, 1 to 10 Vdc) Digital Autozero Solenoid in Offboard
Sequence of Operation AVS Calibration Sequence of Operation The following paragraphs present the sequence of operation for Fume Hood Controller Application 2940, 2-Position Constant Volume Controller with Damper. The Fume Hood Controller can operate at two different setpoints, described as HI flow and LOW flow setpoints. The controller can be set to an OFF mode. In this mode the damper is closed and the controller enters into a standby mode of operation.
Sequence of Operation AO2 Flow Signal AO2 Flow Signal An analog signal of the exhaust flow is available at AO2 of the controller board and is displayed at EXH SIG AO2. To get an output from EXH SIG AO2, you must command AO2 RANGE to the maximum expected flow for the fume hood. Then AO2 is scaled such that 1 Vdc is equal to 0 cfm, and 10 Vdc is equal to AO2 RANGE. If the output drops below 1 Vdc, this indicates a GENERAL FAILURE or loss of power.
Sequence of Operation Control Loop NOTE: If you set DISPLAY RES to zero, the ODP continuously displays the value of EXH FLOW. Resetting DISPLAY RES to a value other than zero displays the EXH FLOW incrementally. The factory default is 5, cfm values displayed will be in increments of 5 (for example, 80, 85, 90, 95, 100, etc.). If the actual filtered cfm is 84, 85 will be displayed. These two points affect the ODP display only; they do not affect the values in the controller or values sent to the network.
Sequence of Operation Alarm Limits Warning and Alarm Schedule. Alarm Limits The Fume Hood Controller contains high and low flow alarm limits, HI ALM LMT and LOW ALM LMT, respectively. The alarm limits are defined as a percentage of the controller setpoint; therefore, the alarm limits apply to EXH STPT during normal control. For either of the alarms to become active, the alarm condition must be maintained for the time specified in ALARM TIME.
Sequence of Operation Start-up/Decommission Mode 1. EMER ALM turns ON, the horn sounds, and the red LED on the ODP illuminates. The ODP displays “EMERGENCY” mode and indicates to close the hood. 2. The Fume Hood Controller commands the damper/Venturi valve to fully open for the time (in seconds) specified in EMER TIMER. 3. After EMER TIMER has timed out, the Fume Hood Controller controls the flow at the flow setpoint, EXH STPT, multiplied by the emergency set point percentage, EMER STPT. 4.
Sequence of Operation Fail Mode The modes are described as an enumerated point: STARTUP MODE Mode Description 0 Normal 2 Non-functional Decommission, closed The controller is fully functional, except the flow setpoint is set to 0, alarming is limited and the ODP displays “Out of service” and “OFF”. If the sash is opened, nothing changes. 3 (default) Non-functional Startup The controller is fully functional, except alarming does not work and the ODP displays “Controller – Startup” and “OFF”.
Sequence of Operation Wiring Diagram Wiring Diagram Offboard Air Module Wiring. CAUTION The FHC-OAVS has two terminal blocks with terminations numbered identically (terminations 1 through 16). DO NOT mix these up with each other. If the FHC-OAVS is not connected as shown, it is not resistant to electrical surges. It is also susceptible to interference from other equipment. CAUTION A separate power supply is required if a 4-20 mA sensor is used.
Sequence of Operation Wiring Diagram 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. NOTE: The controller’s DOs control 24 Vac loads only. The maximum rating is 12 VA for each DO.
Sequence of Operation Wiring Diagram Application 2940 Wiring Diagram. 14 Siemens Industry, Inc.
Point Database Application 2940 Point Database Application 2940 Point Number a), Descriptor Factory Default (SI Units) c) Eng Units (SI Units) c) Slope (SI Units) c) Intercept (SI Units) c) On Text Off Text 1 CTLR ADDRESS 99 -- 1 0 -- -- 2 APPLICATION 2900 -- 1 0 -- -- {05} LOW ALM OFF -- -- -- ON OFF {06} HIGH ALM OFF -- -- -- ON OFF {07} EMER ALM OFF -- -- -- ON OFF {08} GEN FAILURE OFF -- -- -- ON OFF 10 HI ALM LMT 150 PCT 1 0 -- -- 11 HI
Point Database Application 2940 Point Number a), Descriptor Factory Default (SI Units) c) Eng Units (SI Units) c) Slope (SI Units) c) Intercept (SI Units) c) On Text Off Text {42} RETC DO2 RETC -- -- -- HOLD RETC {43} DO 3 OFF -- -- -- ON OFF {44} DO 4 OFF -- -- -- ON OFF {45} HI.LOW DO5 HI -- -- -- LO HI {46} DECOM DO6 OFF -- -- -- ON OFF {47} ALARM DO7 OFF -- -- -- ON OFF {48} AUTOZERO DO8 OFF -- -- -- ON OFF {49} AI 3 0 VOLTS 0.
Point Database Application 2940 Point Number a), Descriptor Factory Default (SI Units) c) Eng Units (SI Units) c) Slope (SI Units) c) Intercept (SI Units) c) On Text Off Text 109 LAMP TEST OFF -- -- -- ON OFF 110 ENG UNITS ENG -- -- -- SI ENG 121 HI LIMIT 1 -- 0.01 0 -- -- 122 LO LIMIT 1 -- 0.01 0 -- -- 123 EMER DI6 OFF -- -- -- ON OFF {125} ODP DISPLAY MODE -- -- -- CFM MODE {126} AVE EXH VOL 0 (0.0) CFM ( LPS) 4 (1.
Point Database Application 2900 Point Database Application 2900 Point Number a), Descriptor Factory Default (SI Units) c) Eng Units (SI Units) c) Slope (SI Units) c) Intercept (SI Units) c) On Text Off Text 1 CTLR ADDRESS 99 -- 1 0 -- -- 2 APPLICATION 2900 -- 1 0 -- -- {36} AVS2 PRESS 0.0 (0.0) IN H2O (K PA) 0.0001 (0.000025) 0 -- -- {37} DI 2 OFF -- -- -- ON OFF {38} DI 6 OFF -- -- -- ON OFF {39} AO 1 0 VOLTS 0.01 0 -- -- {40} AO 3 0 VOLTS 0.
Issued by Siemens Industry, Inc. Building Technologies Division 1000 Deerfield Pkwy Buffalo Grove IL 60089 Tel. +1 847-215-1000 Document ID 140-1317 Edition 2015-11-04 © Siemens Industry, Inc., 2015 Technical specifications and availability subject to change without notice.
