Stanford Research Systems SR620, Руководство пользователя

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Programming Commands 37
SR620 Universal Time Interval Counter
DISP (?) j
The DISP command set the front panel display.
The parameter j controls the display as shown in
the following table:
j Display Codes
0
Mean Value
1 Rel Value
2 Jitter
3 Maximum Value
4 Minimum Value
5 Trigger Threshold
6 DVM inputs
EXPD (?) j
The EXPD command sets the x1000 expand
mode in frequency and period mode. The
parameter j = 1 turns expand ON while j = 0 turns
expand OFF.
Rear Panel Control
CLCK (?) j
The CLCK command sets the source of the
10MHz clock. The parameter j = 0 sets the clock
source to internal while j = 1 sets the source to
external.
CLKF (?) j
The CLKF command sets the frequency that the
SR620 expects at the external clock input. The
parameter j = 0 sets a 10MHz external clock while
j = 1 sets a 5 MHz external clock.
PORT (?) {j}
The PORT command sets or reads the value of
the printer port when that port is configured as a
general purpose I/O port. The parameter j
(0<j<255) is the value sent to the port (in decimal)
if it is an output. If the port is configured as an
output, the -strobe line is strobed low for about
10us every time a valid byte is set.
PRTM (?) j
The PRTM command sets the mode of the printer
port. If j = 0 the port is a printer port, if j = 1 the
port is a general purpose input port, and if j = 2 the
port is a general purpose digital output port.
RNGE (?) j{,k}
The RNGE command sets the input voltage range
of DVM input j ( j = 0,1). If k = 0 the selected
channel is set to autorange, if k = 1 the selected
channel is set to ±20V full scale, and if k = 2 the
selected channel is set to ±2V full scale.
VOLT ? j
The VOLT? query reads the value of the selected
input channel (0 or 1). Values outside the fullscale
range indicate an overload condition.
Interface Control Commands
*RST
The *RST common command resets the SR620 to
its default configurations. It is the same as holding
down "clr rel" at power on. All modes are set to
their default conditions.
*IDN?
The *IDN common query returns the SR620's
device configuration. This string is in the format:
StanfordResearchSystems, SR620, serial number,
version number. Where "serial number" is the five
digit serial number of the particular unit, and
"version number" is the 3 digit firmware version
number.
*OPC (?)
The *OPC (operation complete) common
command/query is a synchronization command
designed to simplify the coordination of commands
that take a finite time to complete. The *OPC
common command sets a bit in a status byte when
all in progress measurements/scans/prints are
complete. The *OPC? common query returns the
value 1 when all in progress
measurements/scans/prints are complete. An
example of the use of this command would be to
ensure that the present measurement is finished
before the answer is read. The command line
STRT;*OPC would start a measurement and set a
status bit when it was done. Thus, by polling the
status bit (or using a GPIB service request) the
host computer would know when the
measurement was done.