Chapter 8. Appendices

8.1 Appendix А - Filter strings

When instruments are being added to the left-hand list, a text filter can be applied to the stream name in order to limit the number of instruments listed.

A valid filter string consists of literal characters, character-sets and wild-cards:

• Literal characters will each match a single character in the string. The comparison is not case-sensitive.

• Wild-cards are asterisks (*) or question marks (?). An asterisk matches any number of characters. A question mark matches any single character.

• Character sets match a single character in the input to a selection or range of possible characters. Each character-set begins with an opening bracket ([) and ends with a closing bracket (]). Between the brackets are listed the possible elements of the set. Each element is a literal character or a range. Ranges are specified by an initial value, a dash (-), and a final value. (Do not use spaces or commas to separate the elements of the set.) The input character matches the set if it is the same as one of the literal characters in the set, or if it is in one of the ranges in the set. A character is in a range if it matches the initial value, the final value, or falls between the two values. All comparisons are case-insensitive. If the first character after the opening bracket of a set is an exclamation mark (!), then the set matches any character that is not in the set.

For example, recall that the last two characters of a stream name represent the component and the tap. So:

• To list only vertical streams from tap 4, the filter string would be

  *z4

  The wild-card * will match any number of leading characters and the z and the 4 are literals which must match the last two characters of the input, constraining them to be Z4 or z4.

• To list the two horizontal components for any tap, a character-set must be used, so the filter string would be:

  *[ne]?

  Here, the wild-card * will match any number of leading characters. The character-set [ne] matches one of N, n, E or e in the penultimate position and the wildcard ? will match any final character.

8.2 Appendix B - Calibration values for calculated streams

In order that Scream can display the calculated streams correctly (with appropriate physical units), new entries are created in the calibration parameters file (calvals.txt). Existing entries from the section for the relevant instruments are duplicated and modified as necessary.

Three entries are required for correct operation of the system: G (gain), VPC and Response. Gain and VPC are unaltered while the response entry is amended by changing "Acceleration" or "Velocity" to "Acceleration", "Velocity" or "Displacement", as appropriate, for each of the calculated streams.

Below are typical entries for a CMG-3V accelerometer. The first section is the original section, which is unchanged; this is followed by the newly-generated sections for the calculated pass-through, velocity and displacement streams.

[AAA-R01]

SERIAL-NOS=V3I28/C688

WO=2616

G=754

VPC=3.198

TYPE=CMG-3V

RESPONSE=20S ACCELERATION

COILCONST=0.02385

CALVPC=3.19

CALRES=51000

[AAAP-R01]

Comment1=Derived from AAA-R01

Comment2=by Scream! AVD Extension application

Serial-Nos=V3I28/C688

WO=2616

G=754

VPC=3.198

Type=CMG-3V

Response=20S Acceleration

CoilConst=0.02385

CalVPC=3.19

CalRes=51000

[AAAV-R01]

Comment1=Derived from AAA-R01

Comment2=by Scream! AVD Extension application

Serial-Nos=V3I28/C688

WO=2616

G=754

VPC=3.198

Type=CMG-3V

Response=20S Velocity

CoilConst=0.02385

CalVPC=3.19

CalRes=51000

[AAAD-R01]

Comment1=Derived from AAA-R01

Comment2=by Scream! AVD Extension application

Serial-Nos=V3I28/C688

WO=2616

G=754

VPC=3.198

Type=CMG-3V

Response=20S Displacement

CoilConst=0.02385

CalVPC=3.19

CalRes=51000

8.3 Appendix C - Revision history