Pulse Output LEDs

Do the LEDs on the WattNode^® Pulse meter flash at the same time a pulse is generated?

No. This would be nice for debugging if your pulse counting equipment isn’t seeing any pulses, but there are a few reasons the WattNode Pulse meter wasn’t designed this way:

• The WattNode meter can be ordered with full-scale pulse frequencies down to less than a pulse per minute (Option Hz), so the LED might stay black (off) for several minutes, then green for several minutes. This would make it difficult to use the LEDs to tell if the meter was operating without waiting several minutes for a flash.
• The WattNode meter can be ordered with full-scale pulse frequencies up to 600 Hz (Option Hz), where the LED would appear solid green, because the eye cannot distinguish such fast flashing.
• The WattNode meter can measure power over a 1500:1 ratio from the lowest to the highest power. This is such a wide ratio that at low power levels, the pulse rate could be very slow, and the LED would appear to be stuck black (off) or green (on) for several minutes.
• The WattNode meter is available with a programmable pulse width (WattNode Pulse – Option PW – Pulse Width). If the pulse width is set very narrow (just a few milliseconds) and the LED flash matched the output pulse, it could be hard to see the LED flash, because it would be on for such a short duration.

Instead, the LED pulse rate ranges from 5 Hz for full-scale power down to 0.5 Hz (one flash every two seconds) at 1% of full-scale. This provides a fairly clear indication of lower and higher power levels, without having the LED flash so fast that the flashes blur together and without flashing so slowly that users have to wait many seconds or minutes to see if it’s going to flash again.

The following table shows the LED flash rate as a function of measured power (percent of full-scale).