SOURce:MODule:CLOCk:FREQuency
Syntax
SOURce:MODule:CLOCk:FREQuency {<frequency>|MIN|MAX|DEF}, <slot>
SOURce:MODule:CLOCk:FREQuency? [{MIN|MAX}, ] <slot>
Description
This command sets the frequency of the clock output signal on the 34951A Isolated DAC Module in the specified slot. Once enabled, the clock signal is output from Pin 24 on the module's D-Sub connector.
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This command is also used with the 34950A Digital I/O Module. Click here to view the corresponding information for use with the 34950A. |
Parameters
|
Name |
Type |
Range of Values |
Default Value |
|
<frequency> |
Numeric |
Desired frequency between 305.2 Hz and 10 MHz.
The module rounds the specified frequency to the nearest integer divisor
of 20 MHz (where n = 2 to
65,536): |
1 kHz |
|
<slot> |
Discrete |
{1|2|3|4|5|6|7|8} |
This is a required parameter |
Remarks
The external clock signal is shared among all four DAC channels (i.e., there are no channel-specific clock outputs available).
To enable the specified frequency to be output from the module, use the SOURce:MODule:CLOCk:STATe command.
If desired, you can use the SOURce:FUNCtion:CLOCk:EXTernal:DIVisor command to divide the external clock frequency. Since the maximum point-to-point rate for trace waveforms on the 34951A is 200 kHz, you must set the divisor such that the resulting clock input is less than 200 kHz. For example, with an external clock input of 2 MHz, the minimum divisor would be: 2 MHz/200 kHz = 10.
The clock frequency setting is stored as part of the instrument state (*SAV command).
A Factory Reset (*RST command), Instrument Preset (SYSTem:PRESet command), and Card Reset (SYSTem:CPON command) will disable the clock output and reset the clock output frequency to 1 kHz.
Return Format
The query command returns the clock output frequency in the form "+1.00000000E+03" for each DAC channel specified. Note that since the module rounds to the nearest integer divisor of 20 MHz, the value returned may be different than the frequency you specified. For example, if you specify 3.0 MHz, the query command will return 3.3 MHz (20 MHz/6). If you specify 300 kHz, the query command will return 298.5 kHz (20 MHz/67).
Examples
The following command sets the clock output frequency for slot 4 to 25 kHz (no rounding required) and enables the output.
SOUR:MOD:CLOCK:FREQ
25E+3,4
SOUR:MOD:CLOCK:STATE ON,4 !Enable
clock output
The following command sets the clock output frequency for slot 4 to 300 kHz (rounded to 298.507 kHz) and enables the output.
SOUR:MOD:CLOCK:FREQ
300E+3,4
SOUR:MOD:CLOCK:STATE ON,4 !Enable
clock output
The following query returns the clock output frequency for slot 4.
SOUR:MOD:CLOCK:FREQ? 4
Typical Response: +2.98500000E+05