Tech Tip: Voltage Output of the SD-RO1 Spot Detector with Relay Output

RLE Technologies customers often want to use our SD-R01 spot detector to drive an external load, like an audible alarm or a pump.  RLE does not currently have a leak detection product with a powered output. The SD-R01, like other RLE Technologies leak detection products, has a non-powered output: a Form C relay output.

The Form C relay output is essentially two switches, one closed or “on” during normal operation, and one open or “off” during normal operation. When a leak is detected, the normally closed (or NC) switch opens or turns “off,” and the normally open (or NO) switch closes or turns “on.”

The relay connection on the SD-RO1 and other RLE products consists of three terminals: one for the NC output, one for the NO output, and a common input (COM) for both sides.

If you want to signal a Normal condition by lighting a green LED and a Leak condition by lighting a red LED, attach the leads of the power source and LEDs to the SD-RO1 as follows:

  • Attach the positive lead of a DC power source for the LEDs to the COM terminal.
  • Attach the positive lead of the green LED to the NC terminal.
  • Attach the positive lead of the red LED to the NO terminal.

After grounding the negative leads of the DC power source and the LEDs, the user has a simple red/green alarm circuit.

If you want to drive a load significantly larger than a pair of LEDs, you can attach a larger power source, AC or DC, to the COM terminal of the relay output.  The SD-RO1 relay can handle up to 1 A @ 24 VDC, or 0.5A resistive @ 120 VAC.  Check the datasheets at www.rletech.com/resources for other RLE product output ratings.

Respectfully,
Ray

As a Design Engineer at RLE, Ray Depew is valuable member of our technical support team and is available to answer any technical support questions you may have. To learn more about making the most of your RLE monitoring systems, contact RLE at sales@rletech.com or customer support at support@rletech.com. We’re available to talk to you in person Monday through Friday, 8 a.m. to 5 p.m. (Mountain Time) at 800-518-1519. You can also search our customer support database at www.rletech.com/support.

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