Code
\\Initiate or open resource here
viOpen(rm, "TCPIP0::156.140.158.252::5025::SOCKET", VI_NULL, VI_NULL, &instrument1);

\\Clear the event status register
viPrintf(instrument1, "*CLS\n");

\\Query 'Who am I?"
viQueryf(instrument1, "*IDN?\n", "%#T", &idn_size, idn);

\\Select measurement
viPrintf(instrument1, "CALC1:PAR1:SEL\n");

\\Reset / Clear all the markers i.e. Marker All Off mode.
viPrintf(instrument1, "CALC1:MARK1:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK2:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK3:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK4:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK5:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK6:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK7:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK8:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK9:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK10:STAT OFF\n");

\\Ensure BW Search Query is off.
viPrintf(instrument1, "CALC1:MARK1:BWID:STAT OFF\n");

\\Marker 1 to on and max search
viPrintf(instrument1, "CALC1:MARK1:STAT ON\n");
viPrintf(instrument1, "CALC1:MARK1:FUNC:TYPE MAX\n");

\\Get or query the marker 1 marker max search stimulus
viQueryf(instrument1, "CALC1:MARK1:X?\n", "%#T", &retval_size, retval);
viPrintf(instrument1, "CALC1:MARK1:FUNC:EXEC\n");

\\Set BW Marker Search Threshold
viPrintf(instrument1, "CALC1:MARK1:BWID:STAT ON\n");
viPrintf(instrument1, "CALC1:MARK1:BWID:THR -3\n");

\\Get or query the BW Search data results - 4 returned values not to include
\\Upper Stimulus nor Lower Stimulus
viQueryf(instrument1, "CALC1:MARK1:BWID:DATA?\n", "%#T", &retval_size, retval);

\\Set markers 2 - 3 and Ref Marker to same marker max value.
viPrintf(instrument1, "CALC1:MARK2:X 173499780\n");
viPrintf(instrument1, "CALC1:MARK2:STAT ON\n");
viPrintf(instrument1, "CALC1:MARK2:ACT\n");
viPrintf(instrument1, "CALC1:MARK3:X 173499780\n");
viPrintf(instrument1, "CALC1:MARK3:STAT ON\n");
viPrintf(instrument1, "CALC1:MARK3:ACT\n");
viPrintf(instrument1, "CALC1:MARK10:X 173499780\n");
viPrintf(instrument1, "CALC1:MARK10:STAT ON\n");
viPrintf(instrument1, "CALC1:MARK10:ACT\n");
viPrintf(instrument1, "CALC1:MARK10:ACT\n");
viPrintf(instrument1, "CALC1:MARK10:X 173499780\n");

\\Assign marker 2 to a -3dB Left Target search
viPrintf(instrument1, "CALC1:MARK2:ACT\n");
viPrintf(instrument1, "CALC1:MARK2:X 0\n");
viPrintf(instrument1, "CALC:MARK2:FUNC:TARG -3\n");
viPrintf(instrument1, "CALC1:MARK2:FUNC:TYPE LTAR\n");
viPrintf(instrument1, "CALC1:MARK2:FUNC:EXEC\n");

\\Assign marker 3 to a -3dB Right Target search
viPrintf(instrument1, "CALC1:MARK3:ACT\n");
viPrintf(instrument1, "CALC1:MARK3:X 0\n");
viPrintf(instrument1, "CALC:MARK3:FUNC:TARG -3\n");
viPrintf(instrument1, "CALC1:MARK3:FUNC:TYPE RTAR\n");
viPrintf(instrument1, "CALC1:MARK3:FUNC:EXEC\n");

\\Ref marker, marker 10 to off
viPrintf(instrument1, "CALC1:MARK10:STAT OFF\n");

\\Query marker 2 and marker 3 
\\These are now lower and upper stimulus values 
viQueryf(instrument1, "CALC1:MARK2:X?\n", "%#T", &retval_size, retval);
viQueryf(instrument1, "CALC1:MARK3:X?\n", "%#T", &retval_size, retval);

\\Reset / Clear all the markers i.e. Marker All Off mode.
viPrintf(instrument1, "CALC1:MARK1:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK2:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK3:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK4:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK5:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK6:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK7:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK8:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK9:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK10:STAT OFF\n");


\\Marker 1 to on and max search
viPrintf(instrument1, "CALC1:MARK1:BWID:STAT OFF\n");
viPrintf(instrument1, "CALC1:MARK1:STAT ON\n");
viPrintf(instrument1, "CALC1:MARK1:FUNC:TYPE MAX\n");
viQueryf(instrument1, "CALC1:MARK1:X?\n", "%#T", &retval_size, retval);

\\Set BW Marker Search Threshold
viPrintf(instrument1, "CALC1:MARK1:FUNC:EXEC\n");
viPrintf(instrument1, "CALC1:MARK1:BWID:STAT ON\n");
viPrintf(instrument1, "CALC1:MARK1:BWID:THR -3\n");
viQueryf(instrument1, "CALC1:MARK1:BWID:DATA?\n", "%#T", &retval_size, retval);