ALARM OUTPUT MODULE The Alarm Output Module (AOM) enables you to use weather station alarms or commands from your computer to automatically start or stop external devices such as indicator lights, audio alarms, sprinkler controllers, relays, or other low-voltage AC or DC loads. The AOM works with the GroWeather™, Energy EnviroMonitor™, or the Heath EnviroMonitor™.
C OMPONENTS The AOM includes the following components. Please make sure you have all listed components before continuing. ✦ Alarm Output Module ✦ Alarm Output Module Cable, 2-foot (0.6 m) ✦ Power Y-Cable ✦ AC-Power Adapter ✦ Two Cable Ties ✦ Three #6 x 1” (25 mm long) Self-Threading Screws ✦ Four Adhesive Pads T OOL AND M ATERIALS N EEDED You will need some of the following tools and materials.
T YPICAL AOM I NSTALLATIONS The AOM may be connected to either the sensor interface module or to the Interface Cable Adapter Module. The two illustrations below show typical AOM installations.
O PENING AND C LOSING THE A LARM O UTPUT M ODULE Remove the cover by pushing down on the tabs at the top until you can remove the tabs from the slots. REMOVING THE COVER Reattach the cover as shown below.
A LARM O UTPUT M ODULE O PERATION The section below provides technical information on the operation of the Alarm Output Module. Installation instructions appear separately below. Circuit Operation AOM CIRCUIT DIAGRAM The Console sends to the Sensor Interface Module (SIM) a serial data word containing one bit for each alarm signal and user- and system-controlled output. From the SIM (or the Interface Cable Adapter Module) this is sent to the Alarm Output Module.
Available Outputs The AOM provides four output contacts which may be selected from the conditions listed below. Each output (except time, daily ET, and the “User” outputs) remains active as longs as the alarm condition exists. The time and daily ET outputs remain active for one minute. The “User” outputs must be activated and deactivated by the user via the WeatherLink Software for that station. Also shown in the table below are the pin assignments for each of the three consoles.
Basic AOM Information The AOM outputs are updated by the console at intervals of approximately 3 seconds. The data are sent twice and checked for agreement before being output, providing a measure of error detection. Note the following information concerning the jumpers, LEDs, switches, and jacks found on the AOM board: ✦ Normally-Open/Closed Jumper (J7) Jumper J7 enables the user to select whether the output “contacts” are normally-open or normally-closed.
✦ Latch Circuit Outputs (L1 and L2) and Red LED Indicators The AOM includes two latch circuits; each has one output contact and a red LED indicator. The latches are set and reset by selected alarms, enabling the user to set up two simple control circuits in which each output “contact” is set on by one alarm and set off by another. (For example, start a fan when the high temperature alarm becomes active and keep it running until the low temperature alarm becomes active.
✦ AOM Cover Label The label on the cover of the AOM provides spaces in which you may write the name of the alarm condition connected to each output (A,B, C, D) and each latch circuit (L1, L2). You may also mark the appropriate check box to indicate whether the AOM is configured so the outputs are normally open or closed.
✦ Selecting between normally-open and normally closed operation If you select normally-open operation, each of the four alarm outputs will close when the alarm connected to that output is active. If you select normally-closed operation, each of the four alarm outputs will open when the alarm connected to that output is active. If using either of the two latch circuit outputs, you must select normally-open operation.
Connecting the Outputs The output devices are photo-coupled MOS transistors. They provide floating “contacts” suitable for low-voltage AC or DC loads, as specified in “Contact Specifications” on page 6. Each output contact is connected between the two like-colored terminals (A, B, etc.) of terminal block J4 (labelled CONTACTS). To make connection to the outputs install the two wires from the external circuit, one to each terminal of the pair, in J4.
AOM Connections for Radio Power-Conserving Options For power conservation when using a solar-battery-powered wireless WeatherLink, the AOM is used to switch radio power ON for only brief intervals. Make the connections for this case as follows: 1. Insert the jumper wire for output D (at J5) into pin jack 13 (at J3). 2. Connect the yellow wire from the Solar Power Kit to the D+ terminal (at jumper block J4). Connect the green wire to D-. 3.
Powering the AOM You may use a separate AC-power adapter for the AOM and the console, or you may use the power Y-cable as shown below to connect power to both the console and the AOM from a single adapter.
Mounting the AOM You may mount the AOM against a wall or other vertical surface or you may simply set it down on a horizontal surface Note: Consult the appropriate shelter manual if installing the AOM in either the Complete System Shelter or the Multi-Purpose Shelter. ✦ To mount the AOM against a wall or other vertical surface, attach the base to the mounting surface using the #6 x 1” screws. Use two screws (as pictured below) when attaching to a stud.
Operation of the Alarm Output Module Page 15
Product Numbers: 7736 Davis Instruments’ Part Number: 7395-085 Alarm Output Module Manual Rev. B Manual (7/7/99) This product complies with the essential protection requirements of the EC EMC Directive 89/336/EC. © Davis Instruments Corp. 1996. All rights reserved.
