Archive for category Pressure

What does NAMUR NE 43 do for me?

People have asked me about setting fault alarms in level transmitter analog signals at 2mA or 3mA levels. What they typically don’t understand is that a two-wire transmitter uses the electrical current below 3.6 mA for its own power and operation. So, a 2.0 mA or 3.0 mA fault indication just isn’t possible. At these low currents, there wouldn’t be enough power to generate the fault indication signal and to keep the transmitter functioning properly. Read the rest of this entry »

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February 2: A day to look back

Yesterday and today, people all over Chicago and the Midwest were looking at pictures from last year. We had 22″ of snowfall in one day. The roads were closed. The airports were closed. Even the Lesman offices were closed. And today’s weather forecast? 45°… in Chicago… in February.

This morning in Pennsylvania, a groundhog named Phil came out, looked back, and saw… his shadow.

All this looking back made me a little reflective myself. I’ve been writing this blog for about 6 months now. So I thought I’d take a minute and recap the articles people keep coming back to read:

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Should I use a chemical seal with my pressure instruments?

Diaphragm seal mounts directly into the process linke to reduce damage to the Bourdon tube.Pressure instruments in contact with the process can take a real beating. Process fluids can corrode the wetted parts and destroy the sensing element.  Media the solidifies can clog the pressure-sensing port.  Or, an installed instrument can affect the process by providing a spot for media remnants to remain after cleaning and purging. Specialized chemical seals deal with these pressure sensing issues.

Here’s a list of questions to ask about your application that will determine if you need a chemical seal with your gauge, switch, or transmitter.

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Pressure transmitter pushbuttons to the rescue!

I took a call the other day from a contractor. He was at the construction site, on deadline, and frantic. He was trying to set the zero and range on a Siemens SITRANS P DS-III pressure transmitter‘s 4-20 mA output. He had a HART handheld communicator, but no device descriptor file (DD) that made the two talk to each other. 

Could I help?  Sure! I just asked, “Do you have a Phillips screwdriver?”

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