Date: Mon, 22 Jan 2001 08:16:24 -0800
From: Russell E Owen
Subject: Re: 2.5-m Obslog 20010119 (MJD 51929)
>Bad TCC Axis Status output:
>---------------------------
>0 0 I SpiderInstAng = -24.581485, -0.005128, 4486678367.65964
>0 0 I TCCStatus="SSS","NNN"; TCCPos=-29.23,53.59,155.68;
>AxePos=105.39,81.16,18.17
>0 0 I SpiderInstAng = -24.581485, -0.005128, 4486678367.65964
>0 0 I TCCStatus="SSS","NNN"; TCCPos=-29.24,53.59,155.67;
>AxePos=101.14,78.29,22.14
>0 0 I SpiderInstAng = -24.581485, -0.005128, 4486678367.65964
>0 0 I TCCStatus="SSS","NNN"; TCCPos=-29.26,53.59,155.66;
>AxePos=97.14,7206.75,26.19
>0 0 I SpiderInstAng = -24.581485, -0.005128, 4486678367.65964
>0 0 I TCCStatus="SSS","NNN"; TCCPos=-29.27,53.58,155.65;
>AxePos=93.34,-5648.78,30.14
>0 0 I SpiderInstAng = -24.581485, -0.005128, 4486678367.65964
>0 0 I TCCStatus="SSS","NNN"; TCCPos=-29.28,53.58,155.64;
>AxePos=89.15,69.31,34.19
>0 0 I SpiderInstAng = -24.581485, -0.005128, 4486678367.65964
>0 0 I TCCStatus="SSS","NNN"; TCCPos=-29.30,53.58,155.63;
>AxePos=85.12,1999.14,38.14
>0 0 I SpiderInstAng = -24.581485, -0.005128, 4486678367.65964
>0 0 I TCCStatus="SSS","NNN"; TCCPos=-29.31,53.57,155.62;
>AxePos=81.21,63.58,42.17
This look normal to me. All three axes are slewing (as indicated by
TCCStatus). TCCPos shows where the TCC would like the telescope to be
(the target position of the axes). AxePos shows the actual position
of the telescope.
Hence AxePos and TCCPos should be equal during tracking, but not
during slewing.
Things to watch for during slewing:
- TCCPos should change very slowly (more rapidly while drift scanning
or going through the zenith cone)
- AxePos should fairly quickly converge on TCCPos. To be precise, it
should converge at the maximum velocity set in the AxeLim block
(except when a slew starts or ends).
- If AxePos is very different than TCCPos for some axis, and is not
changing, then that axis is probably disabled.
- If AxePos overshoots TCCPos for some axis, or diverges from it,
then that axis is running away.
-- Russell