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<div dir="ltr" data-setdir="false">Sean,</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Since you might be interested.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Devices are SSI Technologies P51-500-A-A-I36-5v-000-000 for water pressure and Honeywell SSCDRNN030PAAA5 for cabin pressure.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Jon</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><br></div><div><br></div>
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On Wednesday, July 22, 2020, 12:57:32 PM EDT, Sean T. Stevenson via Personal_Submersibles <personal_submersibles@psubs.org> wrote:
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<div><div id="ydp752c6f45yiv8883491919"><div><div>Jon - What are the specs on your SSI transducer? Are you using voltage, current or unamplified? 15 bits on 500 psia should give you 0.01526 psi resolution, provided the input range of your signal conditioner matches the output range of the transducer. Check that. There could be a range mismatch, and possibly a unipolar / bipolar mismatch which would double the achievable step size (e.g. if that 15 bits corresponds to -10 V to 10 V, but the transducer signal is unipolar etc.).<br clear="none"></div><div><br clear="none"></div><div>You will likely see some temperature drift if the transducer is not temperature compensated within the range of service conditions, and I would also check for grounding of the transducer body, and shielding of the signal cable if it is not 4-20 mA.<br clear="none"></div><div><br clear="none"></div><div>If it is a current transducer, is it loop-powered or independently powered? If it is amplifed (voltage or current signal), check the stability of your power supply. If it's a bridge, that's even more critical. On the signal processing side, check how you are obtaining the reading. Acquisition frequency of the ADC vs display update frequency, etc. It could be that a lowpass filter on the measurement will make it behave better.<br clear="none"></div><div><br clear="none"></div><div>Sean<br clear="none"></div><div><br clear="none"></div><div class="ydp752c6f45yiv8883491919protonmail_signature_block ydp752c6f45yiv8883491919protonmail_signature_block-empty"><div class="ydp752c6f45yiv8883491919protonmail_signature_block-user ydp752c6f45yiv8883491919protonmail_signature_block-empty"><br clear="none"></div><div class="ydp752c6f45yiv8883491919protonmail_signature_block-proton ydp752c6f45yiv8883491919protonmail_signature_block-empty"><br clear="none"></div></div><div><br clear="none"></div><div>‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐<br clear="none"></div><div class="ydp752c6f45yiv8883491919yqt0847155879" id="ydp752c6f45yiv8883491919yqt32545"><div> On Wednesday, July 22, 2020 7:11 AM, Jon Wallace via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br clear="none"></div><div> <br clear="none"></div><blockquote class="ydp752c6f45yiv8883491919protonmail_quote" type="cite"><div style="font-family:times new roman, new york, times, serif;font-size:16px;"><div dir="ltr">Sean,<br clear="none"></div><div dir="ltr"><br clear="none"></div><div dir="ltr">I think you've talked about sourcing pressure transducers in the past, do you have any recommendations for ones that you have found reliable? I'm getting quite frustrated trying to interface the SSI Technologies P51 series with a 16-bit ADC (using 15 bits) and unable to get results that are anywhere close to my calculated/expected results even considering worst case accuracy limits. I don't mind paying more for a sensor that is going to perform close to it's datasheet specs. Specifically, looking for 500 psia with .5% or better accuracy. I'd prefer .25% or better accuracy but can live with .5%.<br clear="none"></div><div dir="ltr"><br clear="none"></div><div dir="ltr">Jon<br clear="none"></div></div></blockquote></div><div><br clear="none"></div></div></div><div class="ydp752c6f45yqt0847155879" id="ydp752c6f45yqt10357">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a shape="rect" href="mailto:Personal_Submersibles@psubs.org" rel="nofollow" target="_blank">Personal_Submersibles@psubs.org</a><br clear="none"><a shape="rect" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" rel="nofollow" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div></div>
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