Posts Tagged process control

Honeywell Increases Analog/Loop Processing Speed on HC900 Process and Safety Controller

Written by: Dan Weise

Good news!  Recent upgrades to Honeywell’s HC900 Process and Safety Controller includes a major update to analog/loop processing speeds. Even though analog/loop cycle time has been 500mS since the early 2000s, early versions of the HC900 controller were only capable of a processing speed of 2x/second.

The upgrade to the HC900 CPU’s microprocessor hardware and an associated firmware update broke that processing speed limit for their SIL-rated CPUs. Honeywell C50S and C70S model CPUs v6.1 will now process analog inputs and loops at a rate of 10x/second (100mS per update). If your process needs additional analog/loop throughput speed, you will benefit from these enhancements to the HC900 systems.

To run at 100mS, a qualified hardware configuration is required:

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Why has 4-20 mA gained so much acceptance and survived so long?

Last month, I presented a webinar for our customers. At the end of Control 101, when we opened the session up for questions, a customer asked about making the choice between 4-20 mA and digital signal outputs.  It got me thinking about this list I put together a while back — one that I pull out whenever customers ask me “Is 4-20 mA still valid?”

The answer: Yes, it is. And here are the 18 reasons I came up with… so far. Read the rest of this entry »

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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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How do I tune a process control loop?

Industry surveys say that nearly half of all processes aren’t accurately tuned. If you read my post on accuracy, stability, and repeatability, you’ll know that a poorly tuned process can result in bad readings, downtime, and wasted materials.

If you use a Honeywell UDC2500, UDC3200, or UDC3500 1/4 DIN universal digital controller, there’s a great built-in function called Accutune that can help make sure your control process is properly tuned.

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