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.

Redesigned RTU PCB

Redesigned RTU PCB

This was a redesign of existing main board with over 300 components of a substation Remote Terminal Unit (RTU).

There were number of new features that had to be implemented requiring complete new layout of the board. I followed number of safety and performance standards as well as the R&D procedures of the ISO9001 certified company.

Since the board was going through a major redesign, I implemented additional changes to reduce the cost of the board by:

• converting all components to SMT type and press fit connectors
• moving all components to one side
• removing 2 internal layers

I used Protel 99SE to update the Schematics and create brand new PCB layout. During the process I kept detail design log and at the end I supervised conformance testing.