ROUTe:CHANnel:ADVance:SOURce
Syntax
ROUTe:CHANnel:ADVance:SOURce <source>
ROUTe:CHANnel:ADVance:SOURce?
Description
This command selects the source to provide the channel advance signal to the next channel in the scan list for external scanning. When the channel advance signal is received, the instrument opens the currently selected channel and closes the next channel in the scan list. The instrument will accept an external TTL trigger pulse, a software (bus) command, or an immediate (continuous) scan trigger.
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This command is valid only when the internal DMM is disabled (see INSTrument:DMM[:STATe] command) or removed from the Agilent 34980A. |
Used With:
34921A through 34925A Multiplexer Modules
Parameters
|
Name |
Type |
Range of Values |
Default Value |
|
<source> |
Discrete |
{EXTernal|BUS|IMMediate} |
EXTernal |
Remarks
For the EXTernal source, the 34980A will accept a hardware trigger applied to the rear-panel Chan Adv Input line (Pin 6). For an external device such as a DMM, the trigger received by the 34980A is normally sourced by the DMM's Voltmeter Complete output signal. The 34980A advances to the next channel in the scan list each time a low-true TTL pulse is received.
For the BUS (software) source, the 34980A is triggered by the *TRG command received over the remote interface. The *TRG command will not be accepted unless the 34980A is in the "wait-for-trigger" state (see INITiate command). If the internal DMM receives an external trigger before the next "waiting for trigger" state, it will buffer one *TRG command and then ignore any additional triggers received (no error is generated).
For the IMMediate (continuous) source, the channel advance signal is always present.
The channel advance signal is ignored unless you have initiated the scan (INITiate command) and have received a scan trigger (TRIGger:SOURce command). Although the ROUTe:CHANnel:ADVance:SOURce command shares some of the same signals as the TRIGger:SOURce command, they cannot be set to the same source (except IMMediate). If you attempt to select the same source, an error is generated and the TRIGger:SOURce is reset to IMMediate.
When the first trigger is received, the 34980A closes the first channel in the scan list without waiting for the specified channel advance source. If the channel advance source is EXTernal and the 34980A receives an event before it is ready, it will buffer one event and then ignore any additional events received (no error is generated).
After the final channel in the scan list is closed, one more channel advance event must be received to complete the scan.
A channel advance signal is not required for digital input or totalizer channels included in the scan list. Measurements on these channels are still performed by the 34980A (no internal DMM required) and do not require synchronization with the external instrument.
Return Format
The query command returns the present channel advance source: "EXT", "BUS", or "IMM".
Examples
The following program segment configures the 34980A for scanning using an external channel advance source. In this configuration, the 34980A advances to the next channel in the scan list each time a low-true TTL pulse is received.
INST:DMM OFF !Disable
internal DMM
ROUT:SCAN (@1001:1020) !Configure
scan list
TRIG:SOUR IMM !Set
trigger source
TRIG:COUN 5 !Set
trigger count
ROUT:CHAN:ADV:SOUR EXT !Set
channel advance source
The following query returns the channel advance source currently selected on the 34980A.
ROUT:CHAN:ADV:SOUR?
Typical Response: EXT