The WMS-T-AL temperature alarm is a microprocessor-based, dual-setpoint temperature alarm suitable for environmental and industrial applications. It sounds an alarm and controls the operation of 2 electrical circuits whenever the temperature reaches either of 2 independently set limits. The temperature range is -40 to 160°F (-40 to 71°C) and the alarm range is the same. The alarms can be selected to operate either greater than or less than the selected temperature setpoint. A liquid crystal display provides readout of the measured temperatures and is also used to display maximum and minimum temperatures, as well as the values of the various alarm parameters using a series of setup menus.
Self-contained relays may be used to control external power relays if high-current loads are to be switched. An audible alarm, which may be silenced if desired, is also included within the WMS-T-AL.
To eliminate erratic or premature operation of controlled devices, the WMS-T-AL includes provision for setting a delay or confirmation interval prior to the initiation of an alarm, and a delay time prior to negating an alarm.
All setpoints and maximum and minimum temperature values are stored in non-volatile memory so that these values are not lost if there is a power failure. The circuits are designed to have high electrical noise immunity to transient spikes generated by loads being switched with the alarm relays.
The temperature sensing probe is similar to a precision thermistor and is designed to measure a wide range of temperatures. The WMS-16THS solar radiation shield is recommended for use with the air temperature probe.
SPECIFICATIONS Temperature Sensor: Precision thermistor Measurement Range: -40 to 160°F (-40 to 71°C) Alarm Range: -40 to 160°F (-40 to 71°C) Resolution: 0.1° Accuracy: ±0.5°F (±0.2°C) Alarm On/Off Delay Range: 0 to 99 seconds Controls: Protected push buttons inside housing Indicators: LEDs for alarm point 1 and 2, 2 line x 16 character LCD [display character size 3 x 8 mm (0.1 x 0.3")] Operating Temperature: Control module only -20 to 50°C (-4 to 122°F) Input Power: 12 Vac or Vdc Current: 50 mA maximum Alarm: Contacts rated 3A @ 24 Vdc/115 Vac, Form "C" (SPDT) configuration Temperature Cable Length: 12m (40'), 2-conductor Weight/Shipping: 1 lb (12 oz)/2 lbs (24 oz)