Guralp Systems Limited
MAN-SWA-0001 Issue M - Scream User's Guide
Section Index: 13.1  Log files 13.2  E‑mail notification

Chapter 13.  Logging and notification

13.1  Log files

As Scream! receives data blocks, it checks that each one is valid and self-consistent. Any errors it detects are highlighted in the ViewInfo window (see section 8.4). They can also be logged to disk.

To specify this file, or to change which types of error are logged, choose File → Setup… from the main menu and move to the Event Log tab. Tick Enable Event log to begin.

The top section of this window lets you select the types of event to be logged:

Block Sequence Errors : A block with an unexpected block number. Blocks received over a data link are marked with a block number, which increases by one for each new block. If Scream! receives a block whose number is out of sequence, it generates this error.

Suspicious System IDs : A block coming from an instrument which is reporting a System ID of zero (i.e. blank). Although the block itself is valid, there may be a problem with the device from which it came.

Invalid Time Code : A block with an out-of-range time-stamp (i.e. greater than 23:59:59).

User Commands : A command initiated by the user which affects the operation of the instrument, e.g. locking, unlocking, centring, calibration, and configuration detection.

Invalid Compression Code : A block with a compression code other than 1, 2, or 4.

Invalid Block Duration : A block which is not a valid number of seconds long, or fraction thereof for higher sample rates. For up to 250sps, GCF blocks must contain a whole number of seconds of data, calculated as number‑of‑samples × sample‑rate. For over 250sps, specific fractions of seconds are allowed. See the online GCF specification for more details.

End Sample Mismatch : A block whose final sample (RIC or reverse integrating constant) does not equal the first sample plus all the differences within the block.

Checksum Errors : A block whose checksum does not match the sum of all the bytes in the block.

Data Discontinuities : Any detected gap in a stream, along with the reason, if known. This includes reboots, clock synchronisations, and intentional gaps in triggered channels, as well as any data lost owing to slow or poor-quality communications links. Status streams hold no duration information and are not checked.

By default, log files are created in the user's directory (Local Settings under Windows), under different names according to the source of the data:

Any events which do not relate to a particular stream are logged in the file scream.log. If you clear the File for each data source check-box, all events are logged to this file.

Log files can become quite large and it is usual to limit their size. To do this, tick Limit to… and set a value in the box. When a log file xxx.log reaches this size, it will be renamed xxx.old, and a new, empty xxx.log file will be created. If the file xxx.old already exists, it is overwritten.

Finally, enter the name of a directory in the text box, or click Browse… to find a suitable directory for saving the log file(s). See the notes about choice of a suitable directory in section 3.3.

13.2  E-mail notification

You can also instruct Scream! to send e-mail to warn the operator when particular events happen. To set this up, choose File → Setup… from the main menu and move to the Email Options tab.

To be able to use e-mail, you will need access to a mail (SMTP) server which will accept messages from the address Scream_SMTP_client@your-hostname. Fill in the IP address or hostname of this server in the SMTP Server box. The Recipient box should contain the e-mail address to which you want the mail sent.

The events you can monitor are: