DS Series Family of Sensors and Controllers
The ASE DS series of sensors and controllers provide a balance between price, sophistication, control capabilities and capacities. The inexpensive DS-2B to the powerful DS-8C all share common design features that increase reliability and reduces downtime. Each unit is housed in a sturdy NEMA 3R enclosure rated for outdoor use. All internal electronic components are specified for -40° C to +85° C operation. The DS-2B, DS-2C, DS-4, DS-5, DS-8, and DS-8C are cUL Listed and European CE EMC directives have been achieved — opening the door for both domestic and overseas use.
If you are tired of throwing old sensors away with no possibility of repair, take a look at the DS series. Unlike “potted” sensors and controllers, every DS unit offers full accessibility to the sensor electronics. This unique design allows configuring the unit and replacing sensor fuses and precipitation sensors in the field. Why replace the whole unit when a $50 precipitation sensor may restore your system to “like new” performance? When transients hit, a 25-cent fuse makes more sense than a $100 sensor replacement.
Tired of stocking 10 different part numbers for the same basic sensor? Every DS unit can be set in the field for 120 VAC or 240 VAC operation. All options and adjustments for each unit are also field selectable. This allows covering all of your requirements while keeping your stock low and lead times short. With our socketed microcontroller design we can provide custom operation with “off the shelf” speed. This also allows field upgrades for those “special” sites where conditions just don’t follow the norm.
All DS sensor/controllers should be specified with optional interface cables. You may select from one of the standard cable sets (see the cable sets list) or specify your own cable set requirements for termination to your existing wiring.
In all cases the DS series provides the maximum in flexibility, reliability, and ease of installation.
Basic Theory of Operation
All DS units operate by detecting temperature through a base mounted thermistor and precipitation using a precipitation sensor. This sensor consists of a printed circuit board etched with interleaved traces mounted in a conduit fitting. The sensor is heated using a self-regulating thermistor. When rain or snow land on the sensor the traces are bridged and a closure is detected. The heater then rapidly evaporates the moisture, clearing the sensor. The sensor for the DS-2B, DS-2C, DS-4, and DS-5 simply screws into the top of the controller enclosure. The DS-6 precipitation sensor can be mounted either on the enclosure or remotely. The DS-8 and DS-8C sensor is intended for remote mounting, either on a feed boom for satellite antenna deicing or in a gutter or downspout for roof deicing.
These signals are then supplied to the microcontroller. Depending on the way the user has configured the sensor the microcontroller determines the appropriate action to perform. For example, the DS-4 contains two control relays. Using the profile selection switch (see the DS-4 data sheet for more information) the controller can close one relay for low temperature detection and the other for precipitation detection. It can also be configured to close one relay when rain is detected and the other when snow is detected. It can also close both relays only when snow is detected, allowing control of larger loads.
Difference between Sensor and Controller
The difference between “sensor” and “controller” denotation involves the “Delay Off” time provided by each configuration. “Delay Off” time is the amount of time the sensor/controller will hold the load control relay(s) closed after the last detection of rain or snow. A sensor is normally considered a device that indicates to another control unit that rain or snow is occurring. The attached control unit is then expected to activate and operate the deicing system as required for the application. Therefore, a sensor has a short delay off time, typically 20 seconds to 2 minutes, in order to provide timely indication of detection without excessive latency or re-triggering.
A controller is expected to not only detect trigger conditions but also to directly control the equipment.
A DS series unit set as a controller provides a longer delay off time, typically 30-90 minutes, allowing the heating system to dry the surface and prevent refreezing.
All DS units except the DS-8 provide a remote “control/monitor” interface, a point where ASE or customer supplied devices can be connected to remotely monitor activation of the system and/or manually activate or disable the controller. Some units also feature a built-in switch to perform these same control functions directly from the sensor. The CDP-2 series Remote Control/Status Panels may be directly connected to any DS series sensor/controller in order to provide both remote control and monitoring of DS sensor/controller operation.