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FLOMEC Oval Gear Flow Meter & Collecting Measurements

Hello All!

 

I am in a bit of a pickle with implementing my FLOMEC OM15 oval gear flow meter with optioned RT14 gauge to my DASYlab Lite 2016 program: The DASYlab worksheet is attached and the flow meter will be the last channel in the beginning module.

 

The docs are attached for the OM15 flow meter and RT14 gauge if you're curious. The flow meter is currently wired as a Reed Switch to the RT14 board using the 4.2.1 analogue wiring configuration, only sans shielded cable. Every important section is highlighted in both manuals so it's easy to find.

 

I then use RT14's wiring configuration 4.3.7 to send loop current to our OMEGA D8400 DAQ box which has been set up for loop power using a channel jumper. I have the test system wired as shown in the diagram below if you're curious (flow meter is what matters).

 

The RT14 gauge is supposed to be programmable to a min / max flow range: I have set it to the min / max of the OM15 flow meter. Whether it was at the factory default values or the adjusted value that I set it to, my milliamps do not change.

 

Here's what a FLOWMEC employee said regarding that 4-20 mA as well: "The 4-20 mA is not set at anything at the factory, because every it will set it at appropriate points for each specific application, assuming the 4-20 mA is even being used. You can set it at whatever point you want that works best for your application." That sure makes it seem like it should change the scale if I key in the OM15's range of ~1-40 LPM.

 

Let me know your thoughts, I am likely switching this to a Hall Effect from a Reed Switch as I have temps that change greater than 10-deg C per minute. Somehow the rep whom set us up at Cross Instrumentation forgot to clear that little detail up or did not have prior knowledge.

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Does the Omega utility software read the data correctly? 

And I didn't see the diagram that you mention? 

 

I also need the actual version of DASYLab, for example 14.0.1.721. Use Help-->About to get it. Modbus keeps getting updated. 

- cj

Measurement Computing (MCC) has free technical support. Visit www.mccdaq.com and click on the "Support" tab for all support options, including DASYLab.
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My apologies CJ the website had timed out and deleted the post so I forgot that diagram when I remade it.

 

I just took care of updating DASYlab to the newer SP1 files so it's 14.0.1.721.

 

My D8400 does read 4 mA with no fluid flow, and it does increase in current when the system starts moving oil. However, that's not all true since I also have a huge issue with stray current. Decimals out in the 6-8 digit placeholder range are significantly affecting my conversions later down the road. DASYlab seems to have no way of truncating the milliamp decimal places which get input into the next module for solving.

 

Here's what I want to have happen:

 

mA to m3/s using the limited unit conversions that DASYlab Lite has available. I am using L/min on my OM15 as the unit-rate to display because I need to make sure the value on my digital meter in DASYlab AND the reading on my RT14 gauge match. This is what's annoying right now as I can't get the data to match perfectly in the raw state because of those 6-8 digit current decimal values that affect the converted values.

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From the manual, they're giving you -20ma to 20ma. 

 

You're using the Modbus module to convert to Amps. 

 

Try just converting to milliamps. If you then need Amps, you can divide by 1000 using an arithmetic function . 

 

DASYLab Lite does not have the Formula module, so to truncate digits, you can write it to a Global Variable that is configured for the number of decimals that you want. Then use a Read Variable to read it again. 

 

DASYLab is using double precision floating point. You're still going to have the possibility of noise in the value. 

- cj

Measurement Computing (MCC) has free technical support. Visit www.mccdaq.com and click on the "Support" tab for all support options, including DASYLab.
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Which manual was stating the +/- 20 mA? I see 4-20 mA in both the OM15 and RT14, with the RT14 having the 22 mA alarm.

 

I did forget about Section 2.3.12 and 2.3.13 in the RT14 manual as well: I originally had it wired to use a powered sensor and with the implementation of the DIN rail terminal blocks, I just forgot to wire the power back.

 

DASY Lab 2016 Lite doesn't have an option for mA as shown in the picture below.

 

The global variable doesn't seem to apply since I would need to mA to be changing and not constant; were you more-so getting at that it can be used as  truncating constant?

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I think that it was the Omega D8400 manual that said that the 16-bit integer represents -20mA to 20mA.

 

About the unit… there’s a really short list there that dates back to V1.

The box will allow you to type anything in that you want. So, type -20 to 20 as the scaling range, and type “mA” for the unit.

 

The note about the global variable was to show you how to truncate. But, it didn't work the way I expected. 

- cj

Measurement Computing (MCC) has free technical support. Visit www.mccdaq.com and click on the "Support" tab for all support options, including DASYLab.
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Here's a technique to truncate. In DASYLab Basic, you could do this with the Formula module. 

 

In DASYLab Lite you need to use the Global Variable computation function as shown below. 

 

2019-10-04-PrintScreen-0004.png

- cj

Measurement Computing (MCC) has free technical support. Visit www.mccdaq.com and click on the "Support" tab for all support options, including DASYLab.
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Thank you for this input CJ, I am going to try this next week and I will let you know how that works. Did you think our scaling range for Amps was weird?

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