Principle of Operation

Advanced Diagnostics

Kayden's CLASSIC, for example, uses an advanced microcomputer to perform continuous self-test diagnostics on the electronics and the sensor elements. Any open or shorted connection will result in an error indication that also opens all output contacts and disables the heater circuitry. An internal watchdog circuit ensures that the microcomputer code is performing as expected and a secondary external watchdog circuit ensures that the microcomputer itself is functioning. Both circuits can force the contacts open, illuminate the fault LED and force the heater off. This prevents any possibility of the heater running out-of-control resulting in excessive temperatures on the probe or a burnt out heater. In addition, the CLASSIC microcomputer utilizes a CPA (constant power anemometer design) but modifies the "constant power" of the heater to prevent extreme conditions.

Intelligent User Controls

The Kayden CLASSIC front panel features very bright daylight-visible LED indicators for easy reading even in direct sunlight. Features made possible by the advanced electronics include three field-selectable full-scale ranges for higher resolution in addition to selecting the upper and lower limits of the scalable 21 LED thermal signal bar graph. The relay-energized modes are adjustable for each individual relay for proper failsafe installations depending on the application and desired alarm state. Each relay responds to an adjustable thermal setpoint or may be set instead to respond to temperature making it possible to run two flow setpoints, one flow and one temperature setpoint, or two temperature setpoints all in one product.

An adjustable power-on bypass delay timer is accessible from the front panel for low flow alarm pump protection applications. This makes it possible to disable a pump on low flow but have it automatically restart in the event of a power interruption. The CLASSIC's 4-20 mA loop output is a representation of the data displayed by the thermal signal bar graph display but is field adjustable for forward or reverse orientation as well as the loop fault values for failsafe monitoring of the loop. Four adjustable set point delay timers help eliminate the need for external controls for applications that require an action to be performed but only after a constant alarm for a set period of time. An example would be a low flow pump shut-off that turns off a dry pump but only if it has been dry for several minutes.

The CLASSIC RCMS (Remote Communications and Monitoring Software) allows all these settings and more to be configured remotely during commissioning and saved as a file or printed for future reference. Using the Kayden RCMS for commissioning even gives you the option of locking the front panel controls to eliminate operator adjustments in the field without first unlocking the front panel remotely.

Choices, Not Options

Kayden electronic modules and sensors provide choices, not options. Other products may boast about a wide variety of input power options, such as 115 AC, 230 AC, 24 DC but fail to point out that the option must be specified at time of order. On the Kayden CLASSIC these are choices since all listed AC and DC input voltages are available at all times. Some manufacturers require all options such as relay-energized mode to be specified at time of order but with the CLASSIC a few button pushes selects your choice of operation modes.

Select Your Perferred Output

If a product is to be extremely flexible it must also have a way of communicating its operation in different ways. The Kayden CLASSIC features not only the traditional dry output contacts of a switch but two sets of contacts configurable in different modes, an isolated loop-powered 4-20 mA current loop for remote monitoring of the thermal signal and RS-485 multipoint MODBUS remote communications. For applications controlled by a PLC (programmable logic controller), multiple Kayden units can be connected to the same communications bus and monitored simultaneously.

Advanced Manufacturing

The design team at Kayden truly understands the phrase "design for manufacturing." The design engineers at Kayden stay with a project right from conception to field support with end users. One of the design guidelines implemented at Kayden is "No Jumpers." This eliminates the need for crawling around on your knees with a flashlight trying to find that little black jumper you almost held on to. All the configuration options on all Kayden products are recorded either by miniature mechanical switches or in non-volatile memory. No loose parts! The output relays are always in vacuum-sealed plastic enclosures, no open frame relays where corrosive elements can deteriorate contacts. All printed circuit boards are either encased in a suitable epoxy or coated with conformal coating to prevent components or leads from being affected by corrosive elements. Larger components include extra bonding and adhesives to combat vibration caused failures. State of the art components and component packaging are used to aid in fully automated Surface Mount Technology assembly.

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