HP 8530A, Руководство по эксплуатации и программированию, Страница: 359 / 439

Programming Examples
Setting the Service Request Mask
After P ower ON, TEST , and F actory Preset, the receiver SRQ mask is set to 0,0 and no changes
in the Primary or Secondary status byte will generate an SRQ. T o enable generation of an SRQ
when one or more of the status bits changes from 0 to 1 (changes from cleared to set), specify
the SRQ mask to sense the change in status . Using the receiver SRQM instruction, send two
bytes , each having a value from 0 to 255, as follows:
OUTPUT Rec;"SRQM 16,0;"
This will cause the receiver to generate an SRQ when bit 4 of the Primary Status byte changes
from 0 to 1.
Detect and service the SRQ according to the computer protocol. Normal completion of a service
cycle clears the receiver status bytes to 0,0 and does not change the SRQ mask.
Examples in the Example Program Listings show various interrupt service routines .
Example 18: Output K ey Code
The key code (as documented in the Keyword Dictionary) is printed for any receiver front
panel key pressed by the user . The receiver is set to issue a SRQ when a key press occurs .
Example 19: HP-IB Triggered Data A cquisition
In this example , HP-IB triggers are used to measure 51 points of data for four parameters . This
is done twice with dierent trigger denitions . The rst sweep measures one point on all four
parameters with each trigger (51 triggers). The second sweep requires a trigger for each point
on each parameter (204 triggers). When HP-IB trigger mode is rst turned ON, and before
sending each trigger , primary status byte bit 2 (ready for trigger) is polled so triggers are not
sent too fast.
Example 20: W ait Required
This example creates a continuously changing display pattern using an endless loop to update
the values for Electrical Delay and P arameter Color . The main feature of this example is the
\W AIT;" command that is sent to the receiver . This forces the display to update each time the
loop is executed. Without the WAIT command the loop might execute several times before
the display updates and certain changes would be missed. Refer to the HP 8530A K eyword
Dictionary entry for W AIT .
Example 21: W ait Not Required.
This example executes an endless loop which steps a marker to a new frequency and then
reads the marker frequency , magnitude , and phase . The OUTPxxxx; commands used to
read the marker value automatically hold o further program execution and ensure that
the receiver has completed all prior instructions before the marker value is output. It is not
necessary to send the receiver a WAIT; before reading the marker .
18-30 HP-IB Programming