Hello,
I've developed a code tree using the evaluation firmware. We are trying to see how stable the PGA970's readings are over temperature.
The far the results are very poor. The LVDT is not in the oven for any of our tests, and we're just trying to get stable readings over temperature for now.
Section 7.3.1.7 of the data sheet describes how to calculate the internal temperature in C, specifically,
GAIN = (CODE_125C – CODE_25C) / 100
T = 25 + (ADC_CODE_READ – CODE_25C) / GAIN
What hardware settings are used to produce a reliable temperature reading with the algorithm provided by TI? There are many gain options, and the CODE_125C, and CODE_25C value seem off. Using the default configuration;
/* Configuring PTAT Gain */
S3_CFG_1_CONFIG(NO_S3_OUTPUT_INV | PTAT_GAIN_1_V_V);
I still need to use CODE_125C/5, and CODE_25C/5 in order to get accurate temperature readings.
Readings for the PGA970 Demod1, and demod2 drift quite a bit over temperature. There is a temperature compensation algorithm discussed in "SLDU024–November 2016-PGA970 Software User's Guide", however I cannot get it to work. What hardware settings are used for DEMOD1 and DEMOD2 to feed the temperature algorithm as provided by TI? (i.e. what would actually work with algorithms provided.)
temp,,demod1,demod2 1519,,8345,11848 1518,,8350,11854 1521,,8350,11854 1523,,8351,11854 1523,,8356,11861 1525,,8360,11870 1523,,8365,11871 1525,,8364,11877 1525,,8368,11875 1531,,8370,11881 1529,,8373,11886 1530,,8373,11894 1533,,8377,11887 1533,,8377,11892 1531,,8379,11900 1534,,8382,11906 1532,,8379,11906 1533,,8384,11908 1535,,8388,11910 1532,,8386,11910 1535,,8390,11911 1537,,8387,11912 1538,,8393,11924 1534,,8386,11917 1535,,8392,11912 1538,,8394,11911 1541,,8392,11922 1537,,8393,11920 1540,,8393,11913 1540,,8394,11924 1537,,8397,11931 1540,,8396,11926 1540,,8398,11923 1541,,8400,11927 1546,,8397,11927 1541,,8396,11923 1543,,8397,11930 1542,,8397,11929 1544,,8399,11932 1542,,8399,11926 1540,,8398,11928 1545,,8396,11933 1543,,8402,11933 1543,,8403,11931 1542,,8399,11930 1542,,8403,11933 1541,,8399,11932 1543,,8403,11927 1545,,8404,11934 1542,,8402,11932 1543,,8404,11935 1545,,8405,11935 1546,,8404,11938 1545,,8404,11936 1543,,8402,11928 1543,,8404,11943 1543,,8401,11931 1543,,8407,11935 1547,,8403,11933 1547,,8409,11938 1545,,8401,11936 1543,,8403,11930 1540,,8407,11939 1545,,8406,11933 1545,,8402,11939 1546,,8407,11936 1545,,8405,11932 1542,,8407,11931 1546,,8401,11929 1541,,8405,11932 1545,,8404,11933 1544,,8405,11934 1544,,8400,11931 1547,,8404,11932 1547,,8404,11935 1542,,8405,11931 1547,,8403,11933 1545,,8404,11933 1547,,8403,11936 1544,,8403,11935 1545,,8405,11930 1542,,8402,11935 1544,,8402,11931 1544,,8406,11932 1548,,8404,11931 1546,,8404,11935 1545,,8406,11937 1544,,8405,11929 1542,,8403,11936 1550,,8400,11932 1546,,8407,11932 1543,,8405,11932 1541,,8405,11933 1547,,8405,11928 1546,,8407,11934 1543,,8406,11928 1543,,8403,11930 1544,,8407,11942 1545,,8406,11930 1545,,8402,11931 1544,,8402,11934 1545,,8404,11926 1546,,8403,11932 1545,,8405,11934 1546,,8403,11934 1547,,8404,11930 1549,,8403,11933 1543,,8404,11932 1544,,8402,11931 1541,,8410,11934 1545,,8402,11932 1545,,8404,11933 1547,,8408,11929 1546,,8403,11931 1550,,8404,11933 1546,,8408,11936 1546,,8407,11936 1546,,8401,11932 1547,,8403,11923 1546,,8404,11929 1545,,8408,11927 1545,,8409,11935 1547,,8402,11933 1545,,8408,11933 1547,,8411,11928 1545,,8404,11932 1545,,8408,11936 1549,,8401,11928 1545,,8406,11936 1547,,8409,11935 1547,,8408,11935 1547,,8408,11936 1546,,8407,11938 1549,,8413,11943 1550,,8411,11947 1549,,8418,11948 1550,,8418,11949 1554,,8421,11960 1551,,8427,11972 1555,,8433,11980 1560,,8437,11981 1560,,8448,11995 1559,,8451,11996 1566,,8454,12017 1567,,8465,12025 1571,,8466,12034 1577,,8479,12044 1580,,8484,12058 1581,,8493,12061 1582,,8494,12075 1586,,8501,12083 1592,,8505,12086 1592,,8516,12103 1595,,8519,12111 1597,,8524,12111 1602,,8534,12125 1601,,8538,12138 1606,,8545,12142 1609,,8552,12152 1608,,8549,12155 1613,,8558,12161 1615,,8558,12175 1617,,8563,12173 1615,,8573,12185 1618,,8571,12192 1621,,8575,12197 1623,,8582,12199 1626,,8583,12198 1625,,8582,12201 1627,,8596,12218 1629,,8589,12215 1629,,8592,12222 1629,,8596,12222 1628,,8599,12229 1633,,8599,12225 1634,,8601,12233 1635,,8607,12231 1635,,8605,12238 1635,,8611,12243 1636,,8613,12244 1640,,8611,12248 1639,,8613,12256 1642,,8611,12247 1639,,8611,12249 1639,,8614,12250 1637,,8611,12250 1641,,8616,12257 1642,,8615,12257 1642,,8619,12259 1641,,8616,12260 1644,,8620,12261 1644,,8616,12266 1646,,8617,12259 1646,,8620,12260 1645,,8623,12264 1646,,8619,12269 1646,,8625,12261 1647,,8620,12265 1640,,8621,12266 1642,,8623,12263 1645,,8619,12261 1647,,8621,12265 1645,,8621,12264 1644,,8622,12266 1645,,8621,12271 1647,,8624,12267 1646,,8623,12267 1647,,8622,12265 1643,,8622,12271 1645,,8620,12265 1645,,8627,12271 1648,,8619,12269 1648,,8623,12267 1648,,8622,12267 1646,,8625,12272 1648,,8622,12267 1648,,8625,12265 1646,,8619,12265 1647,,8625,12265 1649,,8620,12261 1646,,8619,12267 1649,,8621,12271 1647,,8624,12267 1645,,8623,12264 1650,,8623,12265 1650,,8623,12262 1649,,8628,12268 1646,,8626,12272 1646,,8627,12272 1646,,8622,12272 1650,,8625,12272 1645,,8620,12268 1647,,8618,12266 1647,,8623,12267 1645,,8623,12266 1650,,8623,12263 1644,,8620,12267 1648,,8622,12270 1649,,8622,12263 1651,,8620,12264 1649,,8619,12272 1650,,8619,12265 1649,,8620,12265 1651,,8620,12267 1651,,8624,12265 1650,,8618,12266 1647,,8624,12269 1648,,8621,12266 1649,,8623,12272 1649,,8627,12273 1649,,8622,12268 1646,,8621,12268 1651,,8620,12268 1648,,8622,12267 1648,,8623,12264 1647,,8622,12263 1648,,8619,12266 1648,,8620,12265 1647,,8622,12264 1649,,8620,12266 1645,,8616,12261 1646,,8619,12267 1649,,8618,12268 1650,,8616,12263 1646,,8624,12275 1652,,8625,12274 1650,,8624,12279 1649,,8632,12280 1653,,8634,12290 1653,,8643,12297 1656,,8647,12305 1660,,8649,12311 1658,,8656,12317 1662,,8662,12326 1668,,8667,12333 1670,,8676,12345 1671,,8682,12357 1676,,8686,12364 1674,,8694,12375 1682,,8702,12382 1687,,8709,12396 1685,,8714,12401 1691,,8717,12409 1691,,8727,12420 1695,,8732,12432 1697,,8737,12435 1699,,8743,12445 1703,,8747,12456 1706,,8753,12461 1706,,8758,12468 1712,,8761,12476 1710,,8771,12488 1713,,8775,12489 1718,,8776,12498 1717,,8778,12500 1716,,8784,12509 1724,,8789,12516 1725,,8794,12526 1727,,8795,12527 1726,,8794,12526 1730,,8800,12538 1728,,8804,12541 1734,,8806,12542 1734,,8808,12549 1734,,8815,12552 1737,,8815,12555 1735,,8815,12558 1740,,8818,12561 1740,,8821,12564 1739,,8823,12565 1743,,8829,12567 1742,,8824,12570 1739,,8824,12570 1744,,8825,12581 1744,,8825,12579 1743,,8826,12582 1742,,8829,12582 1749,,8828,12584 1747,,8830,12590 1745,,8828,12588 1748,,8829,12585 1747,,8829,12591 1748,,8834,12584 1748,,8834,12582 1750,,8836,12591 1752,,8835,12588 1745,,8836,12594 1748,,8838,12598 1750,,8837,12593 1749,,8841,12599 1749,,8839,12592 1750,,8838,12590 1747,,8837,12595 1752,,8839,12601 1751,,8839,12594 1750,,8841,12595 1750,,8834,12591 1752,,8840,12602 1752,,8838,12600 1750,,8841,12595 1751,,8842,12601 1755,,8842,12603 1750,,8842,12602 1757,,8844,12599 1752,,8838,12595 1753,,8841,12598 1752,,8838,12597 1754,,8843,12597 1752,,8833,12596 1753,,8840,12604 1756,,8841,12602 1753,,8840,12604 1754,,8841,12598 1752,,8840,12603 1754,,8843,12606 1754,,8836,12605 1751,,8840,12607 1755,,8842,12603 1751,,8841,12603 1756,,8843,12603 1754,,8839,12603 1754,,8843,12598 1754,,8840,12601 1755,,8843,12606 1756,,8842,12602 1752,,8839,12605 1755,,8839,12598 1754,,8843,12608 1753,,8841,12599 1753,,8839,12599 1752,,8841,12607 1757,,8841,12600 1757,,8839,12604 1754,,8839,12600 1753,,8841,12605 1756,,8838,12600 1754,,8843,12601 1756,,8837,12599 1756,,8838,12599 1755,,8836,12599 1757,,8834,12601 1757,,8837,12602 1757,,8837,12606 1756,,8837,12603 1759,,8839,12602 1755,,8841,12603 1756,,8842,12600 1757,,8837,12600 1756,,8841,12599 1755,,8844,12608 1754,,8841,12599 1754,,8838,12598 1756,,8839,12602 1757,,8838,12598 1758,,8840,12604 1753,,8840,12608 1753,,8839,12605 1756,,8843,12608 1756,,8849,12612 1756,,8849,12618 1760,,8851,12616 1761,,8859,12628 1766,,8863,12639 1765,,8869,12643 1769,,8873,12653 1769,,8881,12660 1775,,8886,12672 1778,,8893,12679 1780,,8900,12690 1782,,8905,12703 1781,,8911,12707 1787,,8918,12718 1792,,8923,12728 1792,,8928,12735 1796,,8933,12746 1799,,8940,12754 1799,,8943,12757 1803,,8950,12773 1808,,8958,12779 1808,,8961,12790 1812,,8972,12794 1811,,8973,12802 1814,,8979,12809 1814,,8982,12819 1821,,8990,12825 1824,,8992,12830 1826,,8995,12836 1826,,8998,12843 1828,,9003,12844 1830,,9003,12849 1832,,9007,12852 1832,,9012,12859 1835,,9011,12865 1836,,9017,12869 1835,,9021,12873 1836,,9021,12881 1839,,9025,12883 1839,,9029,12888 1838,,9029,12891 1843,,9027,12895 1844,,9033,12896 1843,,9033,12901 1843,,9036,12904 1845,,9039,12900 1847,,9042,12911 1848,,9041,12903 1845,,9040,12904 1844,,9040,12907 1849,,9042,12917 1849,,9049,12913 1849,,9047,12921 1849,,9046,12917 1850,,9052,12917 1847,,9048,12922 1850,,9051,12923 1851,,9053,12921 1851,,9051,12925 1852,,9059,12931 1855,,9057,12931 1855,,9051,12925 1852,,9056,12927 1851,,9057,12926 1853,,9055,12927 1857,,9058,12927 1852,,9058,12931 1853,,9057,12930 1852,,9052,12930 1852,,9053,12936 1855,,9059,12934 1853,,9057,12932 1857,,9058,12935 1856,,9057,12935 1859,,9062,12942 1856,,9057,12932 1855,,9061,12939 1857,,9056,12935 1855,,9060,12939 1856,,9060,12938 1854,,9058,12939 1855,,9058,12939 1858,,9060,12941 1857,,9058,12936 1856,,9058,12939 1856,,9059,12943 1854,,9058,12936 1855,,9060,12942 1859,,9060,12940 1852,,9058,12940 1857,,9062,12941 1858,,9060,12941 1856,,9059,12939 1857,,9060,12943 1859,,9063,12943 1858,,9057,12935 1855,,9059,12937 1858,,9059,12942 1858,,9059,12937 1857,,9057,12937 1858,,9063,12944 1859,,9059,12936 1858,,9059,12943 1857,,9061,12937 1860,,9054,12936 1856,,9055,12937 1859,,9063,12941 1853,,9055,12934 1853,,9053,12935 1860,,9058,12935 1854,,9059,12938 1855,,9061,12936 1856,,9056,12939 1858,,9057,12938 1857,,9060,12935 1858,,9060,12935 1856,,9060,12939 1857,,9059,12933 1858,,9060,12935 1855,,9055,12938 1860,,9052,12934 1855,,9057,12936 1856,,9058,12942 1855,,9056,12936 1857,,9059,12942 1857,,9062,12935 1857,,9058,12938 1858,,9057,12938 1857,,9058,12935 1859,,9056,12942 1854,,9061,12943 1862,,9062,12947 1862,,9067,12949 1861,,9071,12954 1862,,9073,12952 1863,,9077,12966 1870,,9082,12966 1869,,9090,12978 1872,,9092,12986 1870,,9097,12995 1874,,9104,13006 1876,,9110,13016 1879,,9117,13023
