SOURce:FUNCtion:CLOCk:SOURce
Syntax
SOURce:FUNCtion:CLOCk:SOURce <source>, (@<ch_list>)
SOURce:FUNCtion:CLOCk:SOURce? (@<ch_list>)
Description
This command selects the clock source for pacing trace outputs on the specified channels on the 34951A Isolated DAC Module. The module will accept an internal clock, an external clock, or a software (bus) command. If desired, you can assign different clock sources to each of the four DAC channels.
Used With:
34951A Isolated DAC Module
Parameters
|
Name |
Type |
Range of Values |
Default Value |
|
<source> |
Discrete |
{INTernal|EXTernal|STEP} |
INTernal |
|
<ch_list> |
Numeric |
One or more channels in the form (@sccc).
|
This is a required parameter |
Remarks
If you select the INTernal source, the pacing is controlled by the SOURce:FUNCtion:SAMPle:PERiod command.
If you select the EXTernal source, the pacing is controlled by an external clock signal which you supply to the module (Pin 24 on the module's D-Sub connector). The external clock input is shared among all four DAC channels (i.e., there are no channel-specific clock inputs available). The valid frequency range for external clock inputs to the module is 1 Hz to 10 MHz.
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.
If you select the STEP source, the pacing is controlled by the SOURce:FUNCtion:TRIGger:IMMediate command. Successive values are output each time the command is received.
If you select the EXTernal or STEP source, the internal sample period specified by the SOURce:FUNCtion:SAMPle:PERiod command is ignored.
A Factory Reset (*RST command), Instrument Preset (SYSTem:PRESet command), and Card Reset (SYSTem:CPON command) will reset the clock source to INTernal. In addition, storing the instrument state (*SAV command) will reset the clock source to INTernal.
Return Format
The query command returns the present clock source for the specified channels: "INT", "EXT", or "STEP". Multiple responses are separated by commas.
Examples
The following command selects the external clock source on DAC channels 1 and 2 in slot 4. The external clock input is shared between these two channels.
SOUR:FUNC:CLOC:SOUR EXT,(@4001,4002)
The following query returns the clock source in use on DAC channels 1 and 2 in slot 4.
SOUR:FUNC:CLOC:SOUR? (@4001,4002)
Typical Response: EXT,EXT