Guralp Systems CMG-EDU - Manual (Page 37)

Operator's guide
strengths, you will have to multiply values from the MB channel by 256
before comparing them with the normal signals.
5.4.2 SQUAREWAVE
Syntax: Z SQUAREWAVE
Instructs the CD24E1 to inject a square-wave (step function)
calibration signal, consisting of a positive step on the start of the next
clock minute, followed by a negative step some minutes later (by
default, 2). The calibration is disconnected the same number of
minutes after the negative edge.
Z denotes the Z channel of the digitizer. This is used for the CMG-
EDU's single component (whether vertical or horizontal.)
You can alter the duration of each step using the MINUTE command,
described below.
5.4.3 MINUTE
Syntax: duration MINUTE
Sets for how long the next SINEWAVE calibration signal will be
injected, or the period of the next SQUAREWAVE calibration signal.
duration is the desired interval, in minutes. If you now issue a
SINEWAVE command, the calibration will last duration minutes; if
the next calibration command is SQUAREWAVE, a positive step of
duration minutes will be generated, followed by a negative step of a
further duration minutes.
If you do not issue MINUTE, calibration signals will default to 2
minutes. This is to avoid the sensor and digitizer inadvertently being
left in calibration mode. Issuing, e.g., 5 MINUTE will cause the next
calibration signal to last 5 minutes, but later calibration signals will
revert to a duration of 2 minutes. You will need to issue a MINUTE
command before each injection.
Because of the way FORTH works, you can insert MINUTE commands
into SQUAREWAVE or SINEWAVE commands, for example:
N/S 4 HZ 5 MINUTE SINEWAVE
E/W 10 MINUTE SQUAREWAVE
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