Guralp Systems CMG-CD24 - Manual (Page 62)

CMG-CD24
C = M8 to MB
D = MB to MF
The least significant bit is the lower channel within each group (i.e.
M0 = 1 and M3 = 8).
For example, to configure mass position outputs for the first
instrument (M9, MA and MB), the required code would be:
0070
Note:
M8 = Z Mass position
M9 = N/S Mass position
MA = E/W Mass position
MB = Calibration signal (on 3 channel digitisers)
ME = Temperature
5.4.4 COMPRESSION
Syntax: bits size COMPRESSION or NORMAL COMPRESSION
Sets the maximum amount of compression to use. Greater
compression means the digitiser outputs data more efficiently, so more
can be transmitted over a link with a given bandwidth. However,
compressing streams uses processor power and can increase data
latency.
The digitiser compresses data without loss, so compression is most
effective when the data contain relatively little information. In most
cases, when a seismic event occurs, the digitiser will need to decrease
the compression level.
bits can be one of 8BIT, 16BIT and 32BIT. 8BIT (the default) is the
maximum amount of compression; 32BIT denotes no compression.
size determines the maximum number of data samples in a GCF block.
This must be between 20 and 250; the default is 250.
GCF blocks must be a whole number of seconds long. If you set size to
a very small value, so that size samples is less than 1 second for some
streams, the digitiser will output 1 block every second for those
streams, ignoring the value of size.
Thus, if you issue 32BIT 20 COMPRESSION, streams with a sample
rate of 20 samples/s and higher will output one block per second,
62 Issue C