isolator for magnetic pickup sensor

isolator for magnetic pickup sensor

This was a very nice project to build an isolator for industrial machines between the sensor side and output control.

It fit into a small DIN rail mounted enclosure and it had to operate at an ambient temperature over 120°C. This required careful component selection and a lot of power dissipation calculations at the start to ensure that the the natural convection cooling of the component was sufficient to keep the component junction temperature at safe levels. It even included an over temperature shutdown.

As with most industrial scenarios the power supply on both sides was “dirty” with possible spikes and high voltages requiring significant filtering and protection build into the device. The electrical isolation was to 2500V.

It had to provide enough protection and fault detection for easy troubleshooting. The output was current limited and if it was shorted it would have to turn on an LED. Activity on either side had to be easily verifiable by blink of LEDs so a pulse stretcher was used on both sides.

It turned out to work great.

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