posted July 02, 2007 09:31 AM            

For myself watching a continuous digital graph of the 5 second filtered value collected once per second over 15 minutes or so is often enough for troubleshooting. Often I can get the gist of what is going on just by watching the digital number display over that period of time.

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Best Regards,

Tom Cunningham

posted July 09, 2007 11:03 PM            

Tom pointed out a couple of the important considerations. If you want pressure recordings at a fairly slow rate (once per second is the best these will do) they *may* work.

I looked at their description for the model OM-PLPT - that one is supplied with a 500 PSI probe, and doesn't make any mention of using it with anything else. However, I didn't dig deeper ... they may support others.

I didn't see any of these loggers with DC voltage capability (although they do have a 4-20 mA model). Often pressure instruments have a retransmission option for 0-10 VDC, and 4-20 mA, so (if you have a pressure instrument supporting 4-20 mA retrans output)you could use the OM-PL420.

One option you may wish to consider is buying one of the Dataq starter kits - it is an inexpensive way to get your feet wet.
http://www.dataq.com/

They often sell gear via eBay. Right now, they have their 4 channel, 10 bit model DI-194RS starter kit for $25+S&H. It'll do 240 samples/second, and accepts +/-10 VDC input.

If you don't have a retransmission capability on your pressure instruments (or the probes are fed directly into the Husky control system) you'll need a way to convert low millivolt level strain gauge signals to voltage. Typically a strain gauge signal conditioner is used.

Just now, as I was looking to see what Omega sells for conditioners, see thay have a NOMAD data logger specifically for strain gauge input, model OM-CP-BRIDGE110-10. Why they don't show it on the main NOMAD product page is beyond me ...

be careful you pick one with a range suitable to your probes; they show 0-10 mV, 25mV, 100mV, and 1000mV full scale ranges. If you are using 3.33 mV/V gauges with 10 VDC excitation then 33.3 mV is full probe output, and you'll need the 100mV unit to see full range.

The 25 mV unit can be used, but be aware you'll be limited (if full scale output is 33.3 mV) to about 75% of the probe full scale.

In any event, if you want to play around with the Dataq starter kit you'll need a signal conditioner to boost mV strain gauge signals into the 0-10V range. Omega has a couple such units, as well as B&B Electronics, and many others.

It just occurred to me you may be using mA output (rather than mV/V output) probes ...