SafeSmart Level Alarm Relay and Failsafe Probe
The story starts with some rats, quite a while ago.
One of our customers came to see us and together we had a few technical discussions about how to improve the single sensor probe and the MTR relay as an independent high level backup system.
The problem they had encountered was that rats had eaten the probe cable in a number of sites. When the probe isn’t covered by conductive liquid (e.g. wastewater) it registers as an open circuit. When the cable is broken, disconnected, or the target of hungry rodents it also registers as an open circuit. So the high level wasn’t picked up – a major problem.
Their idea was to bring an extra wire from the sensor in the level probe to the alarming relay and have the relay carry out a continuity check.
It seemed like a great idea. When we talked some more about the idea we first proposed one alarm output for both high level and for loss of probe. I think we were trying to work out if we could re-use most of an older product for the new design. That idea didn’t work for them for good reason – their PLC/RTU control system would start the pumps on a high level alarm and run them for a set period, but if the alarm signal was only indicating loss of probe, the well could be almost empty and they might run the pumps dry and airlock them. Then lots of work getting the pumps into service again!
So the product concept became a level alarm relay with two outputs – one for loss of probe, and one for high level.
Like many product companies we then had lots more ideas for other variants, and with all the MultiSmart work we were doing at the time, the product took a lot longer than it should to make it out the door.
Well, we released the SafeSmart level alarm relay today. The part number is Safe-FS.
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