Gentec-EO QUAD-4Track - Manual (Page 11)

QUAD-4Track User’s Manual Revision 2.1 11
The secondary processor uses the data to set the analog out DAC, and must know where
each pulse terminates.
The range byte is 0 to 18, with 0 indicating 2 fJ and 18 indicating 2kJ. Ranges are in
decades.
The period is based on a 135MHz clock, so dividing 135MHz by the period counts will
yield the frequency.
A full scale reading in any range is 3072 counts. To find the value of the pulse, divide it
by 3072 and multiply the result by the range.
To decode the pulse amplitudes, mask off bytes 0 to 11. Channel 1 is bytes 0, 1, and 2, on
to Channel 4 at bytes 9, 10, and 11. Suppose byte 0 is 0x41, byte 1 is 0x39, and byte 2 is
0xC4. 0x41 is an 'A', and 0x39 is a '9'. The third byte has the 0x04 lower nibble to signal
the end of the channel data. The character of interest is the 'C'. There for the pulse
amplitude is 0xA9C, or 2716 counts. The energy measured will be 2716/ 3072 times the
range.
Data Acquisition
When the QUAD-4TRACK Instrument is powered on, it enters the data acquisition state
and waits for a trigger. When a trigger event occurs, the Triggered LED will illuminate
and the Instrument will measure the pulse energy and the period timer. If the instrument
has been commanded by the user to send data, the results will be sent to the com port and
the analog out controller.
Command Set
All host commands and queries must consist of 3 alphabetic characters followed by an
optional argument list. If there is more than one argument, they must be comma
separated. All commands are terminated by a carriage return followed by a line feed. The
format is:
abc<arg1,arg2,…,argN>CR LF
The 3 characters are case independent. If the command has arguments and the argument
is valid, "OK\r\n" is returned unless noted below. If an error occurs, "ERR\r\n" is
returned. If the command has no arguments, it is interpreted as a query if applicable and
the value of the current state of the parameter the command is returned. All returned
parameters are terminated with a carriage return followed by a line feed. All commands/
queries have a LabView VI to implement them. Since the communications is done via a
com port, any software that supports RS232 communications can be used to develop a
custom application using the command set.