Posts Tagged Configuration

Wet rhymes with Set (or how to remember LRV/URV configuration prompts)

Lots of people like the pushbuttons on industrial pressure transmitters because the basic settings that every transmitter needs can be set up without a HART communicator. This includes things like the tag name, engineering units, LRV (Lower Range Value, the zero, or what 4.0mA represents), URV (Upper Range Value, the span, or what 20.0mA represents) and damping (an average or filter factor that dampens noise).

Honeywell ST700 ST800 configuration screenOn the new Honeywell ST700/ST800 series smart transmitters, the tag name and engineering units are easy to configure and self explanatory, but I seem to stumble when setting up the LRV and URV because I’m faced with a non-descript choice. There’s two sets of options (under Transmitter Setup, not Calibration):

Enter LRV
Enter URV
Set LRV
Set URV

OK, either configures an LRV or a URV value, but which is which?  What’s the difference?

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Why doesn’t my LR560 radar’s analog output match the displayed level value?

Siemens SITRANS LR560 radar level transmitterA customer who had had lots of experience with Milltronics and Siemens ultrasonics was installing his first SITRANS LR560 radar level transmitter.  They had worked with it in the shop beforehand, going through most of the settings.  They even tested it by setting it up to shoot against a file cabinet and used a tape measure the check the indicated distance value.

Everything checked out OK in the shop.

When they installed the transmitter on the top of the bin, they changed the transmitter’s sensor mode parameter from the distance mode they used in the shop for testing to level mode.  After aiming, the level value shown in the local display was dead nuts on, but the 4-20mA signal going back to the control room was way off.

The bin was a third full. The 4-20mA showed it about double that.  Not only that, the 4-20 was going in the wrong direction.  The bin was emptying and the HMI reported an increasing level value.  Someone realized that an inverse-acting output was typical of a distance value, so they reconfigured the sensor mode to distanceThat got the 4-20mA much closer to a distance value, but it was still not exactly what it should be, and besides, the goal was to read level, not distance, in the control room.  What was going on?

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The Impact of Background Echoes on Ultrasonic Level Measurement

Photography is a pretty good way to illustrate the importance of background.

Look at the two photographs here. In one, the background is minimal, and focuses your eye on the subject matter. In the other, the background seriously detracts from the subject. Where should you be focusing? What’s most important?

Non-intrusive background makes focus point clear

Hard to discerne the difference between the action and all the stuff happening in the background

 

But unlike photography, where a good background helps you focus on the subject, in the world of non-contact ultrasonic level measurement, even a “good” background has a negative influence.  Background never contributes to a level reading, it only detracts. But Siemens has a built-in function to “cure” for the influence of backgrounds in their level devices. Read the rest of this entry »

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How do I set upper range value and lower range value on a Siemens pressure transmitter?

A customer needed to re-range a Siemens SITRANS P DS III transmitter without applying pressure. He’d read my earlier blog post about using the pushbuttons to program the DS III (Pressure Transmitter Pushbuttons to the Rescue!), and where to find the Z-fold instruction sheet.

All was going to plan, until he started looking for the settings for lower range value (LRV) and upper range value (URV). And then, in an all-too-familiar scenario, he hit a roadblock. The instructions don’t actually mention URV and LRV, the terms he’s familiar with, by name or acronym. So what’s a guy to do?

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