An update to my test setup upgrades

[pHaestus]

Rather than dig up any other old threads, I thought I would make a new post about what I was up to today and where I'm headed over the next couple of weeks. I started with the simplest of all my to do list: replacing the Digitec 5810 thermometers with the Fluke RTD setup graciously donated by BillA. This was actually pretty straightforward! I replaced the junk 2 wire sensors with 2 new 3 wire sensors and plumbed them into the test loop. I don't know if I would recommend the method I used. I had some tubing that fit very very snug onto the RTD housing and I just stuck that sensor/tubing into a quick disconnect in a PVC cross. Works ok (though I got sprayed once lol) but not exactly professional.

The two sensors are 0.04C off from one another with water flowing through them, and they report temperatures that are 0.02 and 0.06C higher than the old inlet probe of my Digitec 5810 (it's still in the loop right now). That's actually surprisingly close I thought.

Bob's Labview vi works perfectly and I can now log the temperatures from the wb inlet and outlet (and air once I get a couple more sensors) with Labview while the MAX6655 software logs CPU temperature.

Next step is slightly more complicated. I have already plumbed the dP xmitter into the loop and now I need to dig up a 24VDC PSU with temp compensation, power that xmitter up, and then calibrate it. Fun fun fun.

[MaxxxRacer]

Looks like your own your way derek. Congrats.

So i take it this is what you were doing all day today?

btw, thanks again for the help with the MAX655 today.

[pHaestus]

actually this was a minor part of the day. I spent about 3 hours building LEGO stuff with my son and generally messing around the house. Good rainy day Sunday fare

[jaydee]

Sounding good pH. I hope people understand the work that goes into this. In the last 2 weeks I spent more hours working on my test bench than I logged at my job. Probably spent more money than I made aswell.

I like the sounds of that dP Xmitter deal. I assume that is used for measuring the pressure drops?

Will any of the Socket A blocks you have mount to the new board?
[off topic rant]
Bah, off to bed. Got to get up at 4:30am, catch a plane to Cali and then work the rest of the day tearing the end off a gas station canopy so we can add 32 feet to it and remodel the rest of it for the next 2 weeks.... At least I will make $3 more an hour on this one, should easily pay for everything I bought thus far plus my bills. [/off topic rant]

[MaxxxRacer]

lol.. Legos are cool. i used to build those all the time.

[BillA]

the 24VDC is not critical at all, drives the current loop
look at the manual, it may run on 12V also ?

[pHaestus]

Ya the specified range is 13.5-24VDC. I have a 13.8V PSU that will work but I was concerned about running into issues if it's output changes as room temperature fluctuates. Is that not an issue?

[BillA]

the problem is not the psu, its the temp stability of the dp xmitter itself
I just plot it and put the correction into the spreadsheet (another advantage of a chamber)
you have a Rosemount, it may be better than the Foxboro units I'm using
I also have some Rosemount and Yokogawa units, I'll ck them for temperature stability next time I calibrate

[pHaestus]

ahh ok. I'll power it up with the 13.8VDC PSU I have around the house tonight then. I guess I need to replumb both lines running to the xmitter with a t and a needle valve at the end of the line to get it to properly fill with water? I just had a tube running straight to it yesterday so of course it didn't bleed properly

[BillA]

you have 2 diaphrams each with connections on either side
on the other sides their should be a low port, drain; and a high port, bleed
you need to bleed from the high port
if you are missing the bleed plugs, get 2 petcocks such as drain car rads

[pHaestus]

You need to just tell me to RTFM and be done with it

[BillA]

man, I had to google that !
lol

[pHaestus]

I normally would do better than this but I didn't really bother to mess with the dP xmitter because I thought I needed another PSU. So that meant I didnt really look at the manual too much. And now I'm at work whilst instrument is at home. So there is my collection of excuses.

Oh I sorted out the problems with the Fluke and amusingly it wasn't the new probe that was reporting "750C", it was the old one that stopped working when I put the new 3-wire one in. I think it was due to not being properly grounded to the shielding afterwards or something. In any case all is well now. I'll replace them with 4 wire RTDs as soon as I find a few new ones.

[pHaestus]

Ok there are just four threaded ports there. Will have to pick up some petcocks I guess at the auto store.

[talcum]

pH,
You want a math function or look up table added to the dP VI?

[BillA]

Originally Posted by pHaestus

Ok there are just four threaded ports there. Will have to pick up some petcocks I guess at the auto store.

eh ?
just 4 ?
each side normally has 4, 2 front and back on cL of diaphram (normally with 'footballs'), and 2 more on the side - high and low ? (relative to the diaphram cL)
is yours different ?
(I have 6 from 3 mfgrs all the same)

[pHaestus]

Ok I went back and looked. There are 4 threaded holes on the front and back; I had the ones on the front used to bolt into the metal stand. It looks to me though like this rosemount IS different. I looked at the manual (imagine that) and it has (opposite to the tubing inlets): "welded drain/vent valve". So presumably the bleeding and draining all happens from that one spot.

//edit: this is it: http://www.rosemount.com/nuclear/Document/4302us.PDF

For the connection to DMM and to the PSU is relatively small silver shielded wire ok? I think what I have here is 24 or 28 guage.

I'm still bidding for more DMMs. By my count I need 1 more. With 2 good DMMs I can easily get the mag flowmeter running and rebuild my test loop to have automation and dT(wb) dP (wb) and Q logged. Then at a later date I'll actually figure out how to use the 3497A as a scanner, use shunts or a circuit to convert the instrument current outputs to voltage readings and then use the second DMM for current to the (as of now unbuilt) die sim. That can wait until I have the die sim in hand though.

I STILL have to buy those PVC flanges from mcmaster. Maybe I can get that order placed before I head to calgary this afternoon...

[BillA]

nuclear
be sure to rotate the thing so the 'vent' is high, I have some 841GMs that are a bitch to bleed that way

[BillA]

BTW, fill the lines with a soln that won't mold, eh ?
(I use a HydrX soln to fill and bleed the lines, with isolation and bleed valves at the DUT)

I just had another battle with algae, that I lost, again
multiple big tanks of warm water, pumps, hoses, valves - all to be cleaned (ASME pump test setup)
"Algae Destroyer Liquid" (0.6% Simazine) @ 1 tsp/10gal is crap, precipitates and dosen't work
going to treat as a swimming pool, clorox

[pHaestus]

I don't know what the hell to use as a coolant. It has to work over a pretty large range of temps unless I want to drain everything to switch between radiator and wb testing. I may just use whatever we have at work for the chiller/recirculators.

[pHaestus]

OK I got the flanges and gaskets ordered from McMaster. I wasn't sure what type of rubber to use so I got SBS and Viton ones. I figured either should be fine. I'm hoping that package gets here early next week.

[BillA]

depends on whether you are using a heat exchanger with your chiller
I run one soln in the bath, and another in the DUT circuit (HydrX)

[talcum]

pH,
Do you want a 5.5 digit DVM card for the 3497 and vi? Ship to the same place?

[BillA]

pH, I missed your edit

wire guage (ignoring TFM), its a current loop but 24 should be ok if not 100', j/k

[pHaestus]

Wow McMaster shipped via purolator on Tuesday afternoon and it was here for pickup Wed am. I wasn't unfortunately so I'll go pick up the flanges and gaskets for the magnetic flowmeter this afternoon and then grab some bolts to put it all together. So I will then have all the liquid-side measurement stuff ready to go I think (I need to check power specs on the flowmeter and verify it also runs at 13.8V).

Yes I would love a DVM card for the 3497A. I got your e-mail Bob and will respond to it when I take a break today at work.