Agilent 4155C/4156C VXIplug&play Driver User’s Guide, Edition 4 2-21
Driver Function Reference
hp4156b_dcl
hp4156b_dcl
This function sends a device clear (DCL) to the instrument.
A device clear will abort the present operation and enable the instrument to accept a 
new command or query. This is particularly useful in situations where it is not 
possible to determine the instrument state. In this case, it is customary to send a 
device clear before issuing a new instrument driver function. The device clear 
ensures that the instrument will be able to begin processing the new commands.
Syntax ViStatus _VI_FUNC hp4156b_dcl(ViSession vi);
Parameters vi  Instrument handle returned from hp4156b_init( ).
hp4156b_error_message
This function translates the error code from an instrument driver function to a 
readable string.
Syntax ViStatus _VI_FUNC hp4156b_error_message(ViSession vi, ViStatus error_number, 
ViChar _VI_FAR message[ ]);
Parameters vi  Instrument handle returned from hp4156b_init( ).
error_number  Error code from the driver function.
message[ ]  Error message string. Returned data. This is limited to 256 
characters.
hp4156b_error_query
This function returns the error codes and corresponding error messages in the error 
queue of an instrument. See If You Have a Problem manual for a listing of the 
instrument error codes and messages.
Instrument errors may occur when you places the instrument in a bad state such as 
sending an invalid sequence of coupled commands. Instrument errors can be 
detected by polling. Automatic polling can be accomplished by using the 
hp4156b_errorQueryDetect function.
Syntax ViStatus _VI_FUNC hp4156b_error_query(ViSession vi, ViPInt32 error_number, 
ViChar _VI_FAR error_message[ ]);
Parameters vi  Instrument handle returned from hp4156b_init( ).