IBM 7220, Instruction Manual

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E-17
Appendix E, ALPHABETICAL LISTING OF COMMANDS
return or carriage return-line feed terminator to the * command, since these
characters will slow down communications.
STR [n] Storage interval control
Sets the time interval between successive points being acquired under the TD or TDC
commands. n specifies the time interval in ms with a resolution of 5 ms, input values
being rounded up to a multiple of 5. The longest interval that can be specified is
1000000 s corresponding to about one point in 12 days.
In addition, n may be set to 0, which sets the rate of data storage to the curve buffer
to 800 Hz. However this only allows storage of the X and Y outputs. There is no need
to issue a CBD 3 command to set this up since it happens automatically when
acquisition starts.
If the time constant is set to 5 ms or longer, then the actual time constant applied to
the stored X and Y output values will be 640 µs, but if it is set to a shorter value then
this will be the time constant actually used.
SWEEP [n] Oscillator frequency sweep start/Stop
Starts/stops the internal oscillator frequency sweep depending on the value of n
according to the following table:
n Frequency sweep status
0 Stop/Pause
1 Run
When a frequency sweep has been defined, applying SWEEP 1 will start it. The
sweep will continue until the stop frequency is reached. If, during the sweep,
SWEEP 0 is applied, the sweep will stop at the current frequency. If SWEEP 1 is
then applied, the sweep will restart from this point. Once the sweep reaches the stop
frequency and stops, the next SWEEP 1 command will reset the frequency to the start
frequency and restart the sweep.
SYNC [n] Synchronous time constant control
At reference frequencies below 10 Hz, if the synchronous time constant is enabled,
then the actual time constant of the output filters is not generally the selected value T
but rather a value equal to an integer number of reference cycles. If T is greater than
1 cycle, the time constant is between T/2 and T. The parameter n has the following
significance:
n Effect
0 Synchronous time constant disabled
1 Synchronous time constant enabled