The registers of each board are listed below using the following columns:
board.name[dimension] permissions DescriptionThe permissions are combinations of:
frame.nsnap rwai The number of averaged 25.6us samples covered by each frame. This is a combination of the hardware integration time and the archive file integration time. The monitor stream interface automatically divides integrated register values by this number to yield averages. As a special case, nsnap is not itself treated in this way (otherwise it would always appear to be unity to monitor clients). frame.record r-a- The scanner record number of the last record in an archived frame. frame.mjd r-a- The Modified Julian Day number of the last record an archived frame (UTC). frame.utc[2] r-a- The UTC expressed as a Modified Julian Date. The first element of the register records the Modified Julian Day number, and the second records the number of milli-seconds into the day. frame.lst r-a- The local sidereal time corresponding to local.mjd,local.utc (milli-seconds). frame.features r-au 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.
gps.id r--- The manufacturer's board ID. gps.control rw-- Writing to this register with bit 0 set, clears pending interrupts, resets the interrupt configuration registers, and clears the FIFO handshaking registers. gps.timereq r--- Reading this register latches the current time into the time readout registers. gps.time_regs r--- The time readout registers. [0] bits 15-7: (unused) 6: Time error > 0.5 micro-seconds 5: Time error > 5 micro-seconds 4: The clock is flywheeling due to the lack of an IRIG-B signal. 3-0: BCD hundreds of days. [1] bits 15-12: BCD tens of days. 11-8: BCD units days. 7-4: BCD tens of hours. 3-0: BCD units of hours. [2] bits 15-12: BCD tens of minutes. 11-8: BCD units of minutes. 7-4: BCD tens of seconds. 3-0: BCD units of seconds. [3] bits 15-12: BCD 1e-1 seconds. 11-8: BCD 1e-2 seconds. 7-4: BCD 1e-3 seconds. 3-0: BCD 1e-4 seconds. [4] bits 15-12: BCD 1e-5 seconds. 11-8: BCD 1e-6 seconds. 7-4: BCD 1e-7 seconds. 3-0: (unused) gps.ack rw-- bit 0: Card sets this to indicate the receipt of a valid packet. Host clears this bit by writing 1 to it. bit 1: (unused) bit 2: Card sets this to indicate when the output FIFO contains a packet. Host clears this bit by writing 1 to it. bit 3: (unused) bit 4: Card sets this to indicate when the output FIFO contains data, and clears it when output FIFO is empty. Host can clear output FIFO by writing 1 to this bit. bits 5-6: (unused) bit 7: Host writes 1 to this register to tell the card to act on a data packet written by the host to the input FIFO. bit 8-15: (unused) gps.cmd rw-- bit 0: If 1, prevent a new event from overwriting a previous event until an unlock is performed. bit 1: If 1, enable periodic time capture. bit 2: Capture events on rising edges when 0, falling edges when 1. bit 3: When 1, enable event-capture. bit 4: When 1, enable time-coincidence strobe. bit 5: Strobe mode (use major and minor time when 1, just minor when 0). In mode 1 a strobe is generated each second. bit 6-7: Output frequency selection (7 is msb): 0 - 10MHz 1 - 5MHz 2 - 1MHz 3 - 1MHz bits 8-15: (unused) gps.fifo rw-- Reads take data from the output FIFO. Writes queue data to the input FIFO. gps.intmask rw-- Interrupt selection mask: bit 0: Enable external-event interrupts. bit 1: Enable periodic output interrupts. bit 2: Enable time coincidence strobe interrupts. bit 3: Enable 1PPS interrupts. bit 4: Enable FIFO packet-available interrupts. bit 5-15: (unused) gps.intstat rw-- Generated interrupts: bit 0: An event was detected at the external-event input. bit 1: A periodic output pulse has occurred. bit 2: A time coincidence strobe has occurred. bit 3: A 1PPS output has occurred. bit 4: A data packet is avaialble in the output FIFO. bit 5-15: (unused) gps.intvec rw-- The interrupt vector. gps.intlevel rw-- The interrupt level.
dio.id r-a- The manufacturer's board id = 0x2000. dio.csr rwa- The board control/status register. Its 32 bits are assigned as follows (0-31). 0-7 - Ignored. These bits remain low regardless of what is written to them. 8-10 - Are interpreted as a 3-bit integer that sets the debounce delay applied to the digital inputs. This can either be zero, which turns off the debounce delay, or a number N between 1 and 7 which sets the delay to 2**(7+N) microseconds. 11-12 - These bits are recorded in the register and and can be read back but they are otherwise ignored by the board. 13 - This bit must be set to 1 to allow signals from the input connector to appear in the input register. 14 - This bit must be set to 1 to allow the value of the output register to be latched to the output conntector. 15 - This controls the fail-led on the face-plate of the board. The LED is turned on by setting this bit to 0. dio.input[4] rwa- Four single byte digital input registers. Note that negative logic is used, so a high signal on the input connector is represented by a low bit in the input register. If we consider the 4 bytes to form a contiguous 32 bit big-endian integer, the bits are assigned as follows: 0-31 - Unused. dio.output[4] rwa- Four single byte digital output registers. Note that negative logic is used, so after computing a bit pattern using the documentation below, be sure to take its complement before writing to the register. If we consider the 4 bytes to form a contiguous 32 bit big-endian integer, the bits are assigned as follows: 0 - Resets the PMAC. 1-2 - Selects between up to 4 optical pointing cameras. 8-31 - Unused.
VME address of dual-port ram = 0x710000 in A24 address space.
pmac.dpram_init -w-- On startup the dual-port RAM start address is written to this location.PMAC command registers.
pmac.cmd_args[8] rw-- The argument vector for commands sent to the PMAC. pmac.cmd rw-- The opcode of a command sent to the PMAC, selected from the PmacOpcode enumerators. pmac.cmd_stat rw-- The status of the command loop, expressed as a bit-wise union of PmacCmdStat enumerators. pmac.halted_posn[3] rw-- When the telescope is halted, this register holds the halted positions of the az, el and deck axes, respectively. pmac.drv_stat rw-- The status of the drive-system, expressed as a bit-wise union of PmacErrorBitValue enumerators.PMAC readout control registers.
pmac.rbuf rw-- Used to read id of the buffer to be read, enumerated by PmacBufID enumerators.PMAC event propagation registers.
pmac.pps_seen rw-- Set to 1 whenever the tracker sees a 1PPS.PMAC configuration registers.
pmac.track_vmax[3] rw-- The maximum tracking velocity to allow, along the az, el and dk axes, respectively, expressed as encoder units per second, scaled byPMAC raw monitoring readout registers.PMAC_LIMIT_VSCALE
andPMAC_CMD_VSCALE
. pmac.slew_vmax[3] rw-- The maximum slewing velocity to allow, along the az, el and dk axes, respectively, expressed as encoder units per second, scaled byPMAC_LIMIT_VSCALE
andPMAC_CMD_VSCALE
. pmac.scan_vmax[3] rw-- The maximum scanning velocity to allow, along the az, el and dk axes, respectively, expressed as encoder units per second, scaled byPMAC_LIMIT_VSCALE
andPMAC_CMD_VSCALE
.
pmac.fast32_a[700] rw-- Fast-readout 32-bit registers of buffer A. pmac.slow32_a[11] rw-- Slow-readout 32-bit registers of buffer A. pmac.slow16_a[28] rw-- Slow-readout 16-bit registers of buffer A. pmac.fast32_b[700] rw-- Fast-readout 32-bit registers of buffer B. pmac.slow32_b[11] rw-- Slow-readout 32-bit registers of buffer B. pmac.slow16_b[28] rw-- Slow-readout 16-bit registers of buffer B.Trajectory specification registers.
pmac.moves[1992] rw-- Ending positions and velocities of various commanded trajectories.The monitoring time-stamp register.
pmac.utc[2] rwa- The start time of the sampling period that yielded the following monitoring information. This is the UTC time of the second at which the monitoring was started, and is expressed in MJD days and milliseconds (rounded down to the start of the second).Decoded PMAC fast-readout monitoring registers.
pmac.sample_times[100] rwa- The timestamps of each of the
100Hz samples, expressed as the number
of microseconds from the start of the
second specified in pmac.utc
.
pmac.measured_az[100] rwa- One second of measured 100Hz
azimuth-axis encoder values, offset by
one turn.
pmac.measured_el[100] rwa- One second of measured 100Hz
elevation-axis encoder values. This
encoder actually measures zenith_angle+90
degrees.
pmac.measured_dk[100] rwa- One second of measured 100Hz deck-axis
encoder values, offset by one turn.
pmac.expected_az[100] rwa- One second of commanded 100Hz
azimuth-axis encoder values, offset by
one turn.
pmac.expected_el[100] rwa- One second of commanded 100Hz
elevation-axis encoder values. This
encoder actually measures zenith_angle+90
degrees.
pmac.expected_dk[100] rwa- One second of commanded 100Hz deck-axis
encoder values, offset by one turn.
PMAC status registers.
pmac.el_temp rwa- The temperature of the elevation motor (degrees C x 100). pmac.az_temp[2] rwa- The temperatures of the two azimuth motors. (degrees C x 100). pmac.el_current rwa- The current in the elevation motor (A x 100). pmac.el_enc_rot[2] rwa- Two additional terms to add to the elevation encoder readings to correct for: [0] - The rotation of the elevation encoder body due to deformation of the deck bearing. [1] - The rotation of the elevation shaft due to changes in the direction of the load vector. These corrections are measured by tilt meters and reported in multiples of 0.01 arcseconds. pmac.el_torque_bias rwa- The torque bias of the elevation motor (A x 100). pmac.az2_torque_bias rwa- The torque bias of the second azimuth motor (A x 100). pmac.x_tilt rwa- Azimuth tilt meter x-tilt (arcsec x 100) When pointing at a source, a positive tilt causes the telescope to point too high. pmac.y_tilt rwa- Azimuth tilt meter y-tilt (arcsec x 100). If could point at a source on the horizon, and one then looked along the bore-site, towards this source, then a positive y-tilt would correspond to a clockwise rotation of the telescope about the bore-sight. pmac.mean_error[3] rwa- The az,el and dk mean azimuth following errors (counts x 100). pmac.rms_error[3] rwa- The az,el and dk RMS azimuth following errors (counts x 100). pmac.az1_phases[2] rwa- Azimuth motor 1 commanded currents of phases A and B. pmac.az2_phases[2] rwa- Azimuth motor 2 commanded currents of phases A and B. pmac.el_phases[2] rwa- Elevation commanded currents of phases A and B. pmac.servo_outputs[4] rwa- The servo outputs of motors azimuth 1, azimuth 2, elevation and deck. The servo outputs are expressed in DAC counts, and converted by the cal file, to the amplitudes of the motor currents. pmac.crash_cause rwa- If motion has stalled, the bits of this register indicate the cause. The bits, which are enumerated by PmacErrorBitValue enumerators, have the following meanings: 0 - Azimuth motor 1 was involved. 1 - Azimuth motor 2 was involved. 2 - The elevation drive was involved. 3 - The deck drive was involved 4 - A position limit was exceeded. 5 - A motor went over-temperature. 6 - Drive instability detected. 7 - Following error too large. 8 - A drive-amplifier error was detected. 9 - A problem with the GPS timebase clock. 10 - A problem with the overspeed clock. 11 - An elevation brake fault. 12 - An enabled motion-program aborted. pmac.drive_status[2] rwa- A bit-map of drive-status flags. drive_status[0]: 0 aena1 (az1_amp). 1 -lim1 2 +lim1 3 fault1 4 fatal_following_error1 5 az_overlap_swith 6 az1_amp_over_current 7 az1_motor_over_temp 8 fault3 (az2_amp) 9 az2_amp_over_current 10 az2_motor_over_temp 11 az_lap_at_startup 12 aena5 (el_amp) 13 -lim5 14 +lim5 15 fault5 16 fatal_following_error5 17 el_overlap_switch 18 el_amp_over_current 19 el_motor_over_temp 20 aena7 21 -lim8 22 +lim8 23 fault8 24 fatal_following_error8 25 dk_overlap_switch 26 dk_amp_reset- 27 dk_lap_at_startup 28 timebase_clock_error 29 overspeed_clock_error 30 Elevation brake fault 31 (Unused) drive_status[1]: 0 az soft or hard +ve end limit set 1 az soft or hard -ve end limit set 2 az1 motor open loop 3 az2 motor open loop 4 el soft or hard +ve end limit set 5 el soft or hard -ve end limit set 6 el motor open loop 7 dk soft or hard +ve end limit set 8 dk soft or hard -ve end limit set 9 dk motor open loop 10 (Unused) 11 Acquired 12 (Unused) 13 Azimuth acquired. 14 Elevation acquired. 15 Deck acquired. 16 Azimuth unstable. 17 Elevation unstable. 18 Deck unstable. 19 Azimuth motion program running. 20 Elevation motion program running. 21 Deck motion program running. pmac.az_axis_enc rwa- The azimuth-encoder reading (counts). pmac.el_axis_enc rwa- The elevation-encoder reading (counts). Actually now this is zenith angle + 90 degrees. pmac.dk_axis_enc rwa- The deck-encoder reading (counts). pmac.el_motor_enc rwa- The encoder readout from the elevation motor. pmac.az_motor_enc[2] rwa- The encoder readouts from the two azimuth motors. pmac.az_axis_pos rwa- The position of the azimuth axis in encoder counts. Unlike pmac.az this extends more than a turn because of the wrap. pmac.el_axis_pos rwa- Because there is no elevation wrap, this is identical to pmac.el_axis_enc. pmac.dk_axis_pos rwa- The position of the deck axis in encoder counts. Unlike tracker.dk this extends more than a turn because of the wrap.
tracker.tick_utc[2] rwa- The UTC of the GPS 1-second tick at which the information below was recorded, expressed in MJD days and milliseconds (rounded to the second). This is the time associated with positions read back from the PMAC, but not the target time of the pointing data. tracker.gps_status rwa- Time-code reader status bits, where the bits are enumerated by GpsStatusBitValue enumerators. Bit 2: Time error > 0.5 micro-seconds 1: Time error > 5 micro-seconds 0: The clock is flywheeling due to the lack of the IRIG-B signal. tracker.lacking rwa- A bitwise union of PointingPar enumerators. Each enumerated bit represents a pointing model parameter that has not been provided yet. (see cbiregs.h for the contents of the PointingPar enumeration). tracker.utc[2] rwa- The UTC date and time as MJD days and milli-seconds. tracker.lst rwa- The local apparent sidereal time (milliseconds). tracker.ut1utc rwa- The value of UT1-UTC (milliseconds). tracker.eqneqx rwa- The value of the equation of the equinoxes (milli-seconds of sidereal time). tracker.mode rwa- The tracking mode: 0: halt - The telescope is halted. 1: slew - The recorded data refer to the target of a slew. 2: track - The recorded data refer to where the telescope was one second ago. 3: scan - The telescope is scanning. These values are enumerated by the MotionMode type in cbiregs.h. tracker.deck_mode rwa- The deck-axis tracking mode, selected from the DeckMode enumeration defined in cbiregs.h. 0: track - The deck angle is tracking the parallactic angle. 1: zero - The deck angle is fixed at the current deck-axis offset. tracker.refraction[3] rwa- The A and B refraction terms received from the weather task (micro-arcseconds), and the currently resulting offset in elevation (milli-arcseconds). tracker.encoder_off[3] rwa- The encoder angles {azimuth,elevation,deck}, at the topocentric zeroes of azimuth, elevation and deck angle (milli-arcseconds). tracker.encoder_mul[3] rwa- The number of encoder counts per turn {azimuth,elevation,deck}. tracker.az_limits[2] rwa- The minimum and maximum allowed wrap-extended azimuth angles (mas). tracker.el_limits[2] rwa- The minimum and maximum allowed elevation angles (mas). tracker.dk_limits[2] rwa- The minimum and maximum allowed wrap-extended deck angles (mas). tracker.tilts[3] rwa- The axis tilts {hour-angle, latitude, elevation} (milli-arcseconds). tracker.flexure rwa- The gravitational flexure of the telescope (milli-arcseconds per cosine of elevation). tracker.axis rwa- The collimation and refraction models being used. Its values are enumerated by the PointingMode enumerator in cbiregs.h. Thus 0 denotes optical pointing, and 1 denotes radio pointing. tracker.collimation[2] rwa- The collimation tilt {magnitude, direction} (milli-arcseconds). tracker.site[3] rwa- The location of the site {latitude (mas), longitude (mas), altitude (mm)}. tracker.source[3] rwa- The source name, encoded as 3 four-byte string segments (see regmap.h for unpack_int_string()). The source name is guaranteed to be terminated by a 0 byte. The max source name length is thus 11. This could change, so the max source name length is enumerated in cbiregs.h as SRC_LEN. tracker.equat_geoc[3] rwa- The geocentric apparent {RA (mas), Dec (mas), Distance (micro-AU)}. This is where the source would appear to be if viewed from the center of the Earth. tracker.equat_off[2] rwa- User-supplied temporary equatorial offsets {RA,Dec} (milli-arcsec). These are added just before the conversion to horizon coordinates. tracker.horiz_geoc[3] rwa- The geocentric apparent {Az,El,Pa} (milli-arcseconds). These are the horizon coordinates at which the source would be seen from the center of the Earth if the telescope could be moved there without rotating it. tracker.horiz_topo[3] rwa- The topocentric apparent {Az,El,Pa} (milli-arcseconds). These are the horizon based coordinates that the source would be seen from at the site, after taking account of horizontal parallax, atmospheric refraction and diurnal aberration. tracker.horiz_mount[3] rwa- The mount {Az,El,Pa} (milli-arcseconds). These are the horizon coordinates at which one has to point the telescope to see the source, after taking account of telescope flexure, the tilt of the azimuth axis, the tilt of the elevation axis, and the collimation errors. tracker.horiz_off[3] rwa- User-supplied offsets in {Azimuth,Elevation,Deck-angle} (milli-arcsec). tracker.sky_xy_off[2] rwa- User-supplied sky-based {x,y} tracking offsets (milli-arcsec), where x and y lie along perpendicular great circles that cross at the un-offset pointing center. The y offset increases towards the zenith, and the x offset increases clockwise when looking down from above the telescope. tracker.actual[3] rwa- The positions of the azimuth, elevation and deck axes that were read from the pmac on the most recent 1-second tick. (milli-arcseconds). tracker.expected[3] rwa- The expected positions of the azimuth, elevation and deck axes at the most recent 1-second tick, for comparison with tracker.actual. (milli-arcseconds) tracker.errors[3] rwa- The residuals after subtracting the elements of tracker.expected[] from tracker.actual[]. (milli-arcseconds). tracker.state rwa- The current tracking status, recorded as one of the TrackingStatus enumerators defined in cbiregs.h. 0 - LACKING At least one critical tracker configuration parameter hasn't been received from the control program. 1 - TIME ERROR The last time received from the GPS time-code reader was invalid. 2 - UPDATING The tracker is responding to a change in conditions such as a new command or configuration parameter received from the control program, or an error condition such as a loss of time sync. 3 - HALTED The telescope is currently halted. 4 - SLEWING The telescope is currently slewing. 5 - TRACKING The telescope is currently tracking a source. 6 - SCANNING The telescope is currently performing a scan. 7 - TOO LOW The telescope is trying to track a source that is below the lower elevation limit of the telescope, so the elevation is being held at this limit. 8 - TOO HIGH The telescope is trying to track a source that is above the upper elevation limit of the telescope, so the elevation is being held at this limit. 9 - OFFLINE The PMAC is off-line. 10 - DISABLED Motion has been disabled, in response to an error. 11 - NO AXES No telescope axes are currently enabled. tracker.off_source rwau This register takes two values, 0 and 1. It is set to 1 if the telescope was known to be off source by the tracker at any time during the archived frame. tracker.x_tilt rwa- The x tilt of the azimuth platform is recorded here when the tilt meter is enabled (mas). Otherwise it is zero. When pointing at a source, a positive tilt causes the telescope to point too high. tracker.y_tilt rwa- The y tilt of the azimuth platform is recorded here when the tilt meter is enabled (mas). Otherwise it is zero. If could point at a source on the horizon, and one then looked along the bore-site, towards this source, then a positive y-tilt would correspond to a clockwise rotation of the telescope about the bore-sight. tracker.rotcor rwa- The sum of the measured rotations of the elevation axis and the elevation encoder body (mas). This is zero when this correction isn't enabled. tracker.corflags rwa- The bitwise union of cbiregs.h::CorFlag correction flags. tracker.camera rwa- The number of the active optical pointing camera. tracker.rotcor_zero[2] rwa- The current zero points of the two components of the rotcor correction (mas). tracker.track_mode rwa- What type of tracking to perform in track mode. The following values are enumerated in cbiregs.h:TrackMode. 0 - DRIFT SCANNING The Right Ascension offset is steadily increased at the sidereal rate. For a sidereal source, the telescope essentially stops moving, apart from making tilt and refraction corrections. 1 - TRACKING SOURCE The telescope follows the source as it moves with the sky. tracker.slew_rate[3] rwa- The az,el and dk slew rates, expressed as a fraction of their maximum speeds, scaled by one million. Note that the scale factor is parameterized as TRACKER_SLEW_RATE_SCALE.
camera.angle rwa- The deck angle at which the sky appears to be upright on the TV display (milli-arcseconds).
weather.utc[2] rwa- The UTC date and time on the weather station clock expressed as a Modified Julian Date. The first element of the register records the Modified Julian Day number, and the second records the number of milli-seconds into the day. weather.int_temp rwa- The internal temperature of the weather station (mC). weather.air_temp rwa- The air temperature around the weather station (mC). weather.battery rwa- The weather-station battery voltage (mv). weather.humidity rwa- The relative humidity (0..1) x 1000. weather.wind_speed rwa- The wind speed measured by the weather station (mm/s). weather.wind_dir rwa- The azimuth from which the wind is blowing (milli-arcseconds). weather.pressure rwa- The atmospheric pressure (ub).
monitor.timestamp2[2] rwa- The UTC of the last readout of serial I/O module 2, expressed as a Modified Julian Day number and the number of milli-seconds into the day. monitor.usable2 rwa- This has the value 1 if serial I/O module 2 is functioning, or 0 if not. monitor.module2[8] rwa- The most recently read values that were read from module 2. monitor.timestamp3[2] rwa- The UTC of the last readout of serial I/O module 3, expressed as a Modified Julian Day number and the number of milli-seconds into the day. monitor.usable3 rwa- This has the value 1 if serial I/O module 3 is functioning, or 0 if not. monitor.module3[8] rwa- The last values read out from module 3. [0] - gen2_X_voltage [1] - gen2_Y_voltage [2] - gen2_Z_voltage [3] - gen2_charge_24V [4..6] - Unused. [7] - gen2_bat_voltage monitor.timestamp4[2] rwa- The UTC of the last readout of serial I/O module 4, expressed as a Modified Julian Day number and the number of milli-seconds into the day. monitor.usable4 rwa- This has the value 1 if serial I/O module 4 is functioning, or 0 if not. monitor.module4[8] rwa- The last values read out from module 4. [0] - gen1_engine_temp [1] - gen1_fuel_temp [2..7] - Unused. monitor.timestamp5[2] rwa- The UTC of the last readout of serial I/O module 5, expressed as a Modified Julian Day number and the number of milli-seconds into the day. monitor.usable5 rwa- This has the value 1 if serial I/O module 5 is functioning, or 0 if not. monitor.module5[8] rwa- The last values read out from module 5. [0] - gen1_X_voltage [1] - gen1_Y_voltage [2] - gen1_Z_voltage [3] - gen1_charge_24V [4..6] - Unused. [7] - gen1_bat_voltage monitor.timestamp6[2] rwa- The UTC of the last readout of serial I/O module 6, expressed as a Modified Julian Day number and the number of milli-seconds into the day. monitor.usable6 rwa- This has the value 1 if serial I/O module 6 is functioning, or 0 if not. monitor.module6[8] rwa- The last values read out from module 6. [0] - chiller0_water_temp [1] - chiller0_compressor_temp [2] - chiller1_water_temp [3] - chiller1_compressor_temp [4] - chiller2_water_temp [5] - chiller2_compressor_temp [6] - chiller_container_air_temp [7] - Unused. monitor.timestamp7[2] rwa- The UTC of the last readout of serial I/O module 7, expressed as a Modified Julian Day number and the number of milli-seconds into the day. monitor.usable7 rwa- This has the value 1 if serial I/O module 7 is functioning, or 0 if not. monitor.module7[8] rwa- The last values read out from module 7. [0] - chiller0_water_level (1V=OK, 0V=Fault) [1] - chiller0_fault (1V=OK, 0V=Fault) [2] - chiller1_water_level [3] - chiller1_fault [4] - chiller2_water_level [5] - chiller2_fault [6-7] - Unused.
monitor.timestamp1[2] rwa- The UTC of the last readout of serial I/O module 1, expressed as a Modified Julian Day number and the number of milli-seconds into the day. monitor.usable1 rwa- This has the value 1 if serial I/O module 1 is functioning, or 0 if not. monitor.module1[8] rwa- The most recently read values that were read from module 1.