Chapter 6, COMPUTER OPERATION
6-27
n Start condition Sample condition Stop condition
0 Ext rising edge - Points = LEN
1 On command Ext rising edge Points = LEN
2 Ext falling edge - Points = LEN
3 On command Ext falling edge Points = LEN
4 Ext rising edge - On HC command
5 On command Ext rising edge On HC command
6 Ext falling edge - On HC command
7 On command Ext falling edge On HC command
8 Ext rising edge - Ext falling edge
9 Ext falling edge - Ext rising edge
Note that in modes 1, 3, 5 and 7 the maximum trigger rate is 1000 Hz and the storage
interval control setting has no effect.
TDC n Take data continuously
Initiates data acquisition. Acquisition starts at the current position in the curve buffer
and continues at the rate set by the STR command until halted by an HC command or
on receipt of a trigger at the TRIG in connector, in accordance with the following
table:
n Start condition Stop condition
0 On command On HC command
1 On command Ext rising edge
2 On command Ext falling edge
Note also that if sent without a parameter the command functions as if TDT 0 had
been sent.
The buffer is circular in the sense that when it has been filled, new data overwrites
earlier points.
TRIGOUT [n] Curve buffer trigger output
The value of n defines the type of trigger output generated when a buffer acquisition
is run in accordance with the following table:
n Trigger
0 Trigger generated once per curve, at start of curve
1 Trigger generated once per point
TRIGOUTPOL [n] Curve buffer trigger output polarity
The value of n defines the polarity of the trigger output generated when a buffer
acquisition is run in accordance with the following table:
n Trigger Output
0 Rising-edge
1 Falling edge
EVENT [n] Event marker control
During a curve acquisition into the standard curve buffer, if bit 13 in the CBD
command has been asserted, the lock-in amplifier stores the value of the Event
variable at each sample point. This can be used as a marker indicating the point at
which an experimental parameter was changed. The EVENT command is used to set
this variable to any value between 0 and 32767.