Index

The list of mount registers.

Mount registers are collected into groups of related registers, refered to as boards. The registers of each board are listed below using the following columns:

 board.name[dimension]    Description

Note that to select one of these registers in telviewer, read_registers etc, it is necessary to prefix the names shown in this web page with: "mount."

Also note that the two right-most columns of the tables of registers, show the raw units used to record the values as integers in the archive files, followed by the floating point units that result after scaling and offsetting these values by the numbers in the mount.cal instrumental calibration file.

Index of boards

frame - The archive frame description board.
telescope - Drive control registers.
tracker - Positional tracking registers.
weather - The virtual weather station board.

The archive frame description board.

frame.record The sequential record number of this frame. This is reset to zero each time that the mount real-time control system is restarted. count count

frame.utc[2] The date and time of the frame, expressed as two elements containing MJD days and milli-seconds, respectively. This register is sought by telcontrol in the register maps of all client systems, and the time that it contains, rounded down to an integer number of seconds, is used to match simultaneous frames from the different systems. days, ms days, ms

frame.utc_status

The usability of the timestamp contained in the above utc register, expressed as a FrameUtcStatus enumerator. The individual bits have the following meanings:

0= GOOD

The timestamp is synchronized with GPS.

1= APPROX

The timestamp is not precise, but should be within a few seconds of the true time.

2= BAD

The timestamp is probably completely wrong.

code

frame.features This contains the union of up to 32 arbitrary feature-designation bits received from the control program during the period covered by the containing archive frame. bits bits

frame.label A string label of up to 12 characters, including the '\0' terminator, which schedule scripts can set to any value by invoking the label command. Typically this is used to indicate what the schedule is doing at the moment, both for display in the viewer program, and to indicate the context of the archived data to off-line analysis software. ASCII string ASCII string

frame.misc[0-9] An array of miscellaneous signed integers, for use by schedules to archive any useful numbers that they derive. Schedule scripts use the record_misc command to record values in this register. integer integer

The telescope drive-control status board.

telescope.utc[0-1] The time of the 1-second tick at which the following information was archived, expressed in MJD days and milliseconds (rounded down to the start of the second). days, ms days, ms

telescope.utc_status

The usability of the timestamp contained in the above utc register, expressed as a FrameUtcStatus enumerator. The individual bits have the following meanings:

0= GOOD

The timestamp is synchronized with GPS.

1= APPROX

The timestamp is not precise, but should be within a few seconds of the true time.

2= BAD

The timestamp is probably completely wrong.

code

telescope.servo_mode

The current servo operating mode, expressed as a PsnServoMode enumerator. These have the following values:

0= HALT

The axes are either halted or being halted.

1= SLEW

The servo is moving to a specified fixed position.

2= TRACK

The servo is following a trajectory.

3= SERVICE

Control has been handed to the hardware that takes the telescope to the service position.

4= STOW

Control has been handed to the hardware that takes the telescope to the stow position.

code

telescope.az_encoder_zero The topocentric angle at which the az encoder count is zero. milli arcsec degrees

telescope.az_encoder_size The number of counts per turn of the azimuth encoder. count count

telescope.el_encoder_zero The topocentric angle at which the el encoder count is zero. milli arcsec degrees

telescope.el_encoder_size The number of counts per turn of the elevation encoder. count count

telescope.adc_volts[0-15] The raw voltages measured by the mount analog to digital converter. mV V

telescope.focus_posn The current focus position. um mm

telescope.focus_target The desired focus position. um mm

telescope.focus_error The difference between the desired and actual focus positions. micro meters milli meters

telescope.tilt_af The aft-fore tilt reading of the azimuth-platform tilt meter. milli arcsec degrees

telescope.tilt_lr The left-right tilt reading of the azimuth-platform tilt meter. milli arcsec degrees

telescope.tilt_temp The temperature of the tilt-meter. milli Celsius Celsius

telescope.drive_status

Drive status flags, expressed as an integer with the following bits:

0: DRIVE POWER ON

The drive power is turned on

1: COMPUTER CONTROL

The drives are under computer control.

2: ACQUIRED

All enabled drives are within the tracking tolerances of their commanded positions.

3: HALTED

All axes are halted

4: ENABLED

At least one axis is enabled.

5: DRIVE ERROR

A drive-error has occurred.

6: CLOCK ERROR.

A problem was detected in the UTC clock

7: TOO LOW

The trajectory went below the lower elevation limit during the last second.

bits

telescope.drive_errors

Drive error flags, expressed as an integer with the following bits:

0: DIO READ ERROR.

A digital-I/O read error occurred.

1: DIO WRITE ERROR

A digital-I/O write error occurred.

2: AIO READ ERROR

An analog-I/O read error occurred.

3: AIO WRITE ERROR

An analog-I/O write error occurred.

4: DRIVE POWER OFF

The power was turned off to the drives.

5: CONTROL DISABLED

The computer control enable switch was off.

6: DRIVE AXIS ERROR

One of the axes has signalled an error.

bits

telescope.missing_pars

A bitwise union of TelServoPars enumerators, indicating missing servo configuration parameters. The bits of this register have the following meanings:

0: AXIS LIMITS

The parameters of the axis_limits command.

1: AZIMUTH OVERLAP

The parameters of the azimuth_overlap command.

bits

telescope.nsample The number of servo updates whose stats are recorded in the following array registers: times, az_actual, az_expected, el_actual, el_expected, az_count, az_diff, az_volts, el_count, el_diff, el_volts. This count can have any value between 0 and the servo frequency plus 1. counts counts

telescope.times[0-10] The timestamps of each of the nsample servo update, expressed as offsets from the timestamp in the utc register. micro seconds seconds

Azimuth axis registers:

telescope.az_status

The azimuth axis status flags, expressed as an integer with the following bits:

0: ENABLED

The azimuth axis is enabled.

1: ACQUIRED

The azimuth axis is tracking within its required tolerance.

2: HALTED

The azimuth axis is halted.

3: (unused)

The azimuth axis position has been clipped to its lower topocentric limit.

4: (unused)

The azimuth axis position has been clipped to its upper topocentric limit.

5: OVERLAP ON

The azimuth overlap bit is on.

bits

telescope.az_errors

The azimuth axis error flags, expressed as an integer with the following bits:

0: OVERSPEED

The azimuth axis was going too fast.

1: UNDERSPEED

The azimuth axis was going too slow.

2: HALT FAILURE

The azimuth axis failed to come to a halt.

3: ENCODER JUMP

The azimuth encoder readout changed too much between servo updates.

bits

telescope.az_count[0-10] The raw azimuth encoder readouts of the last nsample servo updates. count count

telescope.az_actual[0-10] The wrap-extended actual topocentric azimuths deduced from the encoder readouts in az_count. milli arcsec degrees

telescope.az_expected[0-10] The wrap-extended expected topocentric azimuths. milli arcsec degrees

telescope.az_diff[0-10] The az_actual-az_expected differences, wrapped into a range of +/- half a turn. milli arcsec degrees

telescope.az_volts[0-10] The azimuth servo-control voltage. micro volts volts

telescope.az_rms_error The 1-second RMS of az_diff milli arcsec degrees

telescope.az_missing_pars

The bitmap of unconfigured azimuth configuration parameters, expressed as an integer with the following bits:

0: ENCODER PARAMETERS:

The parameters of the encoder_counts command.

1: HALT PARAMETERS:

The parameters of the halt_pars command.

2: UNDERSPEED PARAMETERS:

The parameters of the underspeed_pars command.

3: OVERSPEED PARAMETERS:

The parameters of the overspeed_pars command.

4: ACQUISITION PARAMETERS:

The parameters of the acquisition_pars command.

5: SERVO PARAMETERS

The parameters of the servo_pars command.

6: ENCODER ZERO PARAMETERS

The parameters of the encoder_offset command.

bits

Elevation axis registers.

telescope.el_status

The elevation axis status flags, expressed as an integer with the following bits:

0: ENABLED

The elevation axis is enabled.

1: ACQUIRED

The elevation axis is tracking within its required tolerance.

2: HALTED

The elevation axis is halted.

3: TOO LOW

The elevation axis position has been clipped to its lower topocentric limit.

4: TOO HIGH

The elevation axis position has been clipped to its upper topocentric limit.

5: (unused)

The elevation overlap bit is on.

bits

telescope.el_errors

The elevation axis error flags, expressed as an integer with the following bits:

0: OVERSPEED

The elevation axis was going too fast.

1: UNDERSPEED

The elevation axis was going too slow.

2: HALT FAILURE

The elevation axis failed to come to a halt.

3: ENCODER JUMP

The elevation encoder readout changed too much between servo updates.

bits

telescope.el_count[0-10] The raw elevation encoder readouts of the last nsample servo updates count count

telescope.el_actual[0-10] The wrap-extended actual topocentric elevations deduced from the encoder readouts in el_count. milli arcsec degrees

telescope.el_expected[0-10] The wrap-extended expected topocentric elevations. milli arcsec degrees

telescope.el_diff[0-10] The el_actual-el_expected differences, wrapped into a range of +/- half a turn. milli arcsec degrees

telescope.el_volts[0-10] The elevation servo-control voltage. micro volts volts

telescope.el_rms_error The 1-second RMS of el_diff milli arcsec degrees

telescope.el_missing_pars

The bitmap of unconfigured elevation configuration parameters, expressed as an integer with the following bits:

bits

The Tracker task status board.

tracker.lacking

A bitwise union of PointingPar enumerators. The bits of this integer have the following meanings.

0: SITE

The parameters of the site command.

1: REFRACTION

The atmospheric refraction parameters from the weather task.

2: UT1UTC

The value of UT1-UTC from the ut1-utc ephemeris (see the ut1utc command).

3: EQNEQX

The value of the equation of the equinoxes, sent periodically by the control program.

4: WIND

Wind information for the wind-stow facility.

bits

tracker.utc[0-1] The target date and time of the pointing calculations recorded here, expressed in MJD days and milliseconds. days, ms days, ms

tracker.lst The local apparent sidereal time. milli seconds hours

tracker.ut1utc The value of UT1-UTC. milli seconds seconds

tracker.eqneqx The value of the equation of the equinoxes. milli seconds seconds

tracker.mode

The mode of motion, (a TrkMotionMode enumerator from mount_regs.h). This always has one of the following values:

0= HALT

The telescope is either halted, or in the process of being halted.

1= SLEW

The telescope is being slewed

2= TRACK

The telescope is tracking a source

3= SERVICE

The telescope has been commanded to go to the service position.

4= STOW

The telescope has been commanded to go to the stow position.

code

tracker.state

The state of the current mode of motion, (a TrkMotionState enumerator from mount_regs.h). This always has one of the following values:

0= WIND_STOW

The telescope has been temporarily stowed due to excessive winds, and no further motion will be allowed until the wind-stow condition has expired.

1= PENDING

The new mode of motion in tracker.mode will be started as soon as possible. Usually this will occur at the start of the next second. However this state will persist indefinitely if no axes are enabled, or if tracker.lacking indicates that an essential configuration parameter has not been provided.

2= ACQUIRING

The telescope is acquiring the target of the current motion mode.

3= ACQUIRED

The telescope has acquired the target of the current motion mode.

4= OFFLINE

The telescope drives are offline. This means that either the drive-power is turned off or the computer-enable switch is turned off.

code

tracker.refraction[0-1] The A and B refraction terms. micro arcsec degrees

tracker.refraction[2] The offset in elevation caused by the above refraction A and B terms. milli arcsec degrees

tracker.grav_tilt[0-1] The northerly and easterly inclinations of the local direction of gravity to the geocentric vertical. milli arcsec degrees

tracker.meter_tilt[0-1]

The smoothed but not model-corrected aft-fore and left-right tilt meter readings. The model-corrected readings that were used to compensate for the azimuth tilt, were given by,

  meter_offset[i] + meter_tilt[i] * meter_scale[i],

where i=0 denotes the aft-fore tilt, and i=1 the left-right tilt.

milli arcsec

degrees

tracker.meter_scale[0-1] The pointing-model scale factors used to correct the corresponding elements of meter_tilt[0-1]. Note that since these are corrections to the instrumental calibration factors, they should nominally have values around unity. 1000000 * factor factor

tracker.meter_offset[0-1] The pointing-model zero-offsets used to correct the corresponding elements of meter_tilt[0-1], after they have been scaled by meter_scale[0-1]. milli arcsec degrees

tracker.model_offset[0-1] The pointing-model azimuth and elevation offsets that were added to the target position. milli arcsec degrees

tracker.collim_offset The collimation correction perpendicular on the sky to the direction of changing elevation. Positive values increase the azimuth of the telescope by approximately collim_offset * cos(elevation) milli arcsec degrees

tracker.offset_tc The change in the model azimuth and elevation zero-offsets per degree celsius. milli arcsec/degree_celsius degrees/degree_celsius

tracker.flexure The gravitational sag of the telescope per cosine of elevation. milli arcsec degrees

tracker.twind_flex The sag of the telescope per mph^2 of tail-wind. milli arcsec degrees

tracker.site[0-1] The latitude and longitude of the telescope. milli arcsec degrees

tracker.site[2] The altitude of the telescope. milli meters meters

tracker.source The name of the target source (a '\0' terminated source name, encoded as an array of four-byte string segments). ASCII string ASCII string

tracker.equat_geoc[0] The geocentric apparent Right Ascension of the target source. milli arcsec hours

tracker.equat_geoc[1] The geocentric apparent declination of the target source. milli arcsec degrees

tracker.equat_geoc[2] The geocentric distance of the target source. micro AU AU

tracker.equat_off[0-1] User-supplied equatorial offsets (Right Ascension and Declination). milli arcsec degrees

tracker.horiz_geoc[0-1] The geocentric apparent azimuth and elevation of the target source. milli arcsec degrees

tracker.horiz_topo[0-1] The topocentric apparent azimuth and elevation of the target source. milli arcsec degrees

tracker.horiz_mount[0-1] The mount azimuth and elevation of the target source. milli arcsec degrees

tracker.horiz_offset[0-1] The mount azimuth and elevation of the target source, plus any mount azimuth and elevation offsets. milli arcsec degrees

tracker.horiz_actual[0-1] The current positions of the azimuth and elevation axes. milli arcsec degrees

tracker.horiz_error[0-1] The difference horiz_actual-horiz_offset (Azimuth and elevation) milli arcsec degrees

tracker.axis_offsets[0-1] User-supplied azimuth and elevation offsets. milli arcsec degrees

tracker.sky_xy_off[0-1] Sky-based offsets (x,y), with y directed towards the zenith along the great circle that joins the zenith and the un-offset pointing center, and x directed along the perpendicular great circle that goes through the unoffset pointing center and is perpendicular to y. milli arcsec degrees

tracker.corflags

The bitwise union of CorFlag correction flags. The bits of this integer have the following meanings:

0: TILT METER ENABLED

The tilt meter is enabled.

1: TILT METER BAD

The tilt meter reading was out of range and thus was not applied.

bits

tracker.track_mode

When tracking a source, this indicates the type of the source, expressed as a TrackMode enumerator. This can have any one of the following values:

0= DRIFT SCAN

The tracker is doing a drift scan.

1= TRACKING SOURCE

The tracker is following a source on the sky.

2= TRACKING GEOCENTRIC

The tracker is tracking a fixed geocentric az,el,dk position, plus variable tracking offsets.

3= TRACKING TOPOCENTRIC

The tracker is tracking a fixed topocentric az,el,dk position, plus variable tracking offsets.

4= TRACKING MOUNT

The tracker is tracking a fixed mount az,el,dk coordinate, plus variable tracking offsets.

5= TRACKING OFFSET

The tracker is tracking a fixed mount az,el,dk position, and ignoring tracking offsets.

code

tracker.sun_topo[0-1] The topocentric apparent azimuth and elevation of the sun. milli arcsec degrees

tracker.sun_dist The distance between the sun and where the telescope is currently pointing. milli arcsec degrees

tracker.tail_wind The speed of the wind arriving perpendicular onto the back of the dish. milli mph mph

The virtual weather station board.

weather.utc[0-1] The date and time reported by the weather station in MJD days and ms. days, ms days, ms

weather.status

The status of the weather readout, as a WxStatus enumerator. This register can take the following values:

0= NO SERVER

The weather_url command has either not been invoked in the startup script, or its URL was invalid.

1= NO DATA

The most recent attempt to get data from weather server failed.

2= MISSING DATA

One or more of the required parameters was not provided by the weather server.

3= CORRUPT DATA

The latest data received from the weather server did not conform to the expected format.

4= FROZEN DATA

The timestamp that the weather station included with the most recent weather data, was no different than that of the previous update.

5= USABLE DATA

The most recent weather update succeded in updating the weather registers.

code

weather.air_temp The air temperature around the weather station. milli C C

weather.dew_point The dew-point temperature around the weather station. milli C C

weather.humidity The relative humidity. 0.1% %

weather.wind_speed The 2-minute averaged wind speed measured by the weather station. mph mph

weather.wind_dir The azimuth from which the wind is blowing. milli arcsec degrees

weather.gust_speed The peak wind speed of the last hour. mph mph

weather.pressure The absolute atmospheric pressure. micro bar milli bar

Martin Shepherd (27-Jun-2010)