5 Logging

The log database defines all information that characterizes the environment in which a specific observation was obtained. It represents the logbook of telescope operation. It uniquely associates a scheduled observing programme to a set of acquired exposures.

The log database includes night reports and the log files defined in section 3.2 .

The log files will record a number of actions and parameters which are defined in the corresponding dictionaries. In addition, log files may temporarily include any number parameter records to be used e.g. for trouble shooting purposes.

The log file format is designed to allow an accurate trace of VLT operations. Every log record is uniquely identified by the logging source (given through the source mask, see below) and its date/time stamp. This design allows to merge all log records in the log database independently of how many log files where created. The unique source mask also permits to trace the parallel operation of two instruments, e.g. one doing science exposures while the other is used to acquire calibration frames.

5.1 Log File format

A log file consists of maximum 250 byte long records terminated with a newline character (n ), however keywords and values (see below) must be written within the first 72 characters. The restriction to 72 characters is due to the need to be able to include relevant log records in the FITS headers of observations.

Log records have the general format:

hh:mm:ss> keyword / comments [ <source mask>]

hh:mm:ss>/ comments [ <source mask>]

where:

hh:mm:ss> is the time stamp, consisting of the time (UTC). hh:mm:ss.sss> may be used if a higher time resolution is required;
keyword is a hierarchical keyword (or set of words) which explains what happened ( action keyword) or identifies the reported parameter (followed by = value ). Note that the words HIERARCH ESO are omitted here.
comments explain the keyword reported, and
[ <source mask>] is the event source identification mask (see section 5.2 ).

A log file always starts at noon (UTC). The first record of a log is a date stamp record in the following format:

12:00:00> DATE = `YYYY-MM-DD' / Weekday Month Day, Year [source]

A date stamp record must also be the first record written on the log after midnight (UTC).

The following classes of records can be found in a log :

Action records reporting an action initiated by the PI/Co-I; typical examples are opening and closing operations, or moving the telescope. An action record starts with an action keyword (a verb starting with a dash); it cannot have any associated value, but may be followed by parameter record(s) like the telescope slew at the end of the log example on page page 36 . Subsystem names ar taken from table 8 . See section 5.1.1 for the record syntax.
Parameter records These can be meteorological parameters (wind speed, dome temperature), seeing conditions, or the status of some instrument. The parameter name is normally followed by a value. Such parameters are either acquired periodically (e.g. the dome temperature), or recorded as a result of a given action. See section 5.1.2 for the record syntax.
Unforeseen event records , reporting unexpected events, like the failure of a lamp or the loss of synchronization between modules. See section 5.1.4 for the record syntax.
Alarm event records , reporting alarm conditions. See [5.1.5] for the record syntax.
Comments inserted by the PI/Co-I or science operations staff. See section 5.1.6 for the record syntax.
Typical examples of what can be found in the log are given below.

12:00:00> DATE = `1995-03-31' / Fri Mar 31, 1995 [wemmi] 12:46:19>-START COMP / Computer restarted [wemmi] 12:46:19> COMP ID = `HP RTE-A V5' / Operating system identifier [wemmi] 12:46:19> COMP NAME = `NTI` / Network node identifier [wemmi] 12:46:19> TEL ID = `ESONTT` / Control NTT telescope [wemmi] 12:47:35>-START OBS SOFW EMMI / EMMI observ. prog. started [wemmi] 12:47:35> OBS SOFW ID = `OBST-V4.2' / Program name-version [wemmi] 12:47:35> OBS SOFW MODE = `NORMAL' / Hw enabled for OBST [wemmi] 12:47:48>-START INS SOFW EMMI / EMMI control prog. started [wemmi] 12:47:48> INS SOFW ID = `EMMI-V4.1' / Program name-version [wemmi] 12:47:48> INS SOFW MODE = `NORMAL' / Hw enabled for EMMI [wemmi] 12:47:48>-START DET SOFW EMMI RED / CCD control prog. started [wemmiR] 12:47:48> DET SOFW ID = `CCDR-V4.2' / Program name-version [wemmiR] 12:47:48> DET SOFW MODE = `NORMAL' / Hw enabled for CCDR [wemmiR] 12:47:49>-START DET SOFW EMMI BLUE / CCD control prog. started [wemmiB] 12:47:49> DET SOFW ID = `CCDB-V4.2' / Program name-version [wemmiB] 12:47:49> DET SOFW MODE = `NORMAL' / Hw enabled for CCDB [wemmiB] 12:47:54>/UNFORESEEN: Error while initialising EMMI Red CCD [wemmi] 12:47:57>/UNFORESEEN: Error while initialising EMMI Blue CCD [wemmi] 12:47:57>-STOP ADA B LAMP-0 / Calibration lamp switched off. [wemmiB] 12:48:50>-STOP ADA B LAMP-0 / Calibration lamp switched off. [wemmiB] 12:50:17>-START DET EMMI RED / Start wiping CCD EMMI RED [wemmiR] 12:50:17>-START EMMI CALIBRATION / Start cal. procedure [wemmi] 12:50:17>-START ADA B OPTI / Calibration unit moved in [wemmiB] 12:50:17>-CLOSE EMMI CAL SHUT-ALL / Close all cal. shutters [wemmi] 12:50:18>-CLOSE ADA B SHUT-0 / Calibration shutter closed. [wemmiB] 12:50:18>-STOP EMMI CAL LAMP-ALL / Switch off all cal. lamps [wemmi] 12:50:18>-STOP ADA B LAMP-0 / Calibration lamp switched off. [wemmiB] 12:50:19>-START EMMI CAL LAMP14 / Switch on cal. lamp [wemmi] 12:50:19>-START ADA B LAMP14 / Calibration lamp switched on. [wemmiB] 12:50:19>-OPEN EMMI CAL SHUT14 / Open cal. shutter [wemmi] 12:50:20>-OPEN ADA B SHUT14 / Calibration shutter open. [wemmiB] 12:51:16>-START EXPO EMMI RED / Start exp. on CCD EMMI RED [wemmiR] 12:51:16> EXPO EMMI RED NO = 3107 / Exp. num. on CCD EMMI RED [wemmiR] 12:53:17>-STOP EXPO EMMI RED / Stop exp. on CCD EMMI RED [wemmiR] 12:53:17>-READ DET EMMI RED / Reading CCD EMMI RED [wemmiR] 12:55:01>/UNFORESEEN: Failed image transfer to host [wemmiR] 12:55:08>/RECOVERY: Image transfer to host recovered [wemmiR] 12:55:08>-STOP TRANS DET EMMI RED / Transf. OK from CCD EMMI RED [wemmiR] 12:55:08> DET PARM(1) = -8.05, 3.00, 23.52 / DET: VLO1, VHI1, VDD1 [wemmiR] 12:55:08> DET PARM(4) = -4.06, 5.99, 13.77 / DET: HLO1, HHI1, VDR1 [wemmiR] 12:55:08> DET PARM(7) = -0.36, 12.00, 0.31 / DET: RLO1, RHI1, VGS1 [wemmiR] 12:55:08> DET PARM(10)=-14.73, 14.80, 27.34 / DET: -15V, +15V, +30V [wemmiR] 12:55:15>-CLOSE EMMI CAL SHUT14 / Close cal. shutter [wemmi] 12:55:15>-CLOSE ADA B SHUT14 / Calibration shutter closed. [wemmiB] 12:55:15>-STOP EMMI CAL LAMP14 / Switch off cal. lamp [wemmi] 12:55:18>-STOP ADA B LAMP14 / Calibration lamp switched off. [wemmiB] 22:56:12>-MOVE TEL PRESET NTT / Initiate new tel position [wt5tcs] 22:57:37> TEL RA = 67.265296 / RA (deg) after move [wt5tcs] 22:57:38> TEL DEC = -36.328608 / DEC (deg) after move [wt5tcs]

5.1.1 Action records

The general structure of an action record is:

hh:mm:ss>- action_verb category [ subsystem(s) ] / comments [ <source mask>]

TABLE 15 Logging action verbs
Keyword	Meaning
`-ABORT`	Abort an executing action (e.g. an exposure)
`-PAUSE`	Pause an executing action (e.g. an exposure)
`-RESUME`	Resume a paused action (e.g. an exposure)
`-OPEN`	Open any system (e.g. a shutter)
`-CLOSE`	Close any system
`-MOVE`	Move some piece (e.g. the telescope)
`-CHANGE`	Change some piece (e.g. a filter in a wheel)
`-START`	Start or switch on a system (e.g. the exposure)
`-STOP`	Stop or switch off (e.g. a lamp)
`-READ`	Start a reading procedure (typically detector readout)
`-WRITE`	Start a writing procedure

The first keyword in an action record is one of the verbs listed in table 15 ; such keywords start with a dash, and can therefore easily be located, even visually, in the log. If any parameter is required (e.g. move the telescope to some (a, d ) position), an action record is normally followed by one or several parameter records .

Subsystem names are taken from table 8 .

5.1.2 Parameter records

A parameter record will have the general structure

hh:mm:ss> category [ subsystem(s) ] parameter [( start_index )]= value(s) / comments [ <srcmask>]

where subsystem and parameter names follow the guidelines given in section 4.3 .

5.1.3 Parameter arrays

When necessary, arrays of numbers may be logged as several numbers separated by commas. Arrays are recognized by the parenthesized start_index preceding the `=' sign, like the DET PARM values logged in the log example on page page 36 .

The start_index starts from 1; if all values of the array cannot be recorded in a single line, similar lines with adequate values for start_index will be written.

Each value of the array is written in a free–format form, but the values must be separated by commas. Null (non-existent) values are allowed, they are given as a double hyphen `--' .

5.1.4 Unforeseen event records

The log files also include the record of events that are considered unforeseen by the control software. Such events are typically the failure of a calibration lamp or loss of time synchronization.

The record format is

hh:mm:ss>/UNFORESEEN: followed by a succinct description of the error event [ <src mask>]

Recovery records are used to signal the success of an action in response to an unforeseen event, they have the format

hh:mm:ss>/RECOVERY: followed by a description of a recovery measure [ <source mask>]

In some cases it may be desirable to be able to match a recovery log entry to its corresponding unforeseen event. This can be done by filtering log records with the source mask, under the assumption that one single subsystem is issuing only few of such events at a given time.

5.1.5 Alarm records

Alarm events are recorded in the log with the following format

hh:mm:ss>/ALARM: followed by a succinct description of the alarm event [ <source mask>]

5.1.6 Comment records

Two different comment record formats are provided. They have the following structure:

hh:mm:ss>/ free–format comment up to 50 characters

hh:mm:ss>/COMMENT NN free–format comment, possibly spanning several lines

where NN is a two letter code meaning `OB ', `NA ', `RC ' or `SA ' for observer, night assistant, remote control assistant and staff/service astronomer respectively.

Data Interface Control Document

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