HP 8340A Operating Manual page 217

The equipment required is the same as in the pre­
vious example. Reset the 9826A and scratch the
9826A memory. Now type in the above program
and run it. Then perform the following:
2. Adjust the
Then press
NOTE
The resolution of start and stop frequencies
will probably be different. This is normal
because the frequency resolution changes as
(AF)
the sweep width
4. The CW Frequency is set to 20 GHz and power
level to 15 d. B m. Since the specified power at
this frequency is +3 dBm (figure 3), the power
will be unleveled. The OR statement outputs
the real output power value which differs from
the ENTRY DISPLAY and is shown in the POWER
dBm display. The two values are printed on the
9826A CRT.
Another method to quickly transfer parameters
which define a typical sweep is to use the Output
Coupled Parameter statement OC. This statement
outputs three values representing:
1. Start Frequency in Hertz
2. Center Frequency in Hertz
3. Sweep Time in Seconds
Modify the above program by typing in the follow­
ing lines:
PROGRAM (continued)
6
290 DISP "PRESS CONTINUE"
PAUSE
300
310 'OUTPUT COUPLED PARAMETERS
OUTPUT S01"FAPLODBOC"
320
330 ENTER so,F,G,H
PRINT
340
350 PRINT "START FREQUENCY
360 PRINT "CENTER FREQUENCY
370 PRINT "Sll l EEP TIME
380 END
EXPLANATION:
On line 320, the 8340A is programmed to Output
Coupled Parameters.
On line 330, the three parameter values are put in
variables F for Start Frequency, G for Certer Fre­
quency, and H for Sweep Time.
value with the knob.
value with the knob.
is changed.
on the
is"1F/1.E+6,"MHz"
is"1G/1.E+6,"MHz"
is",H*1000,"msec"
Scans by HB9HCA and HB9FSX
On lines 350 to 370, parameter values are dis­
played on the 9826A CRT. Frequencies are dis­
played in megahertz and sweep time in milli­
seconds.
Run the modified program and the coupled
parameters will be displayed on the 9826A CRT.
E X AMPLE P R O G R AM
Requests, Status Bytes, and Request Mask
Certain error conditions of the 8340A can be
detected by the 9826A so that corrective action
can be taken. A few examples of detectable error
conditions are RF power unleveled, RF unlocked,
programming syntax error and power failure. If an
error condition exists, the user can instruct the
8340A to request service from the
initiating a Service Request (SRQ). The 9826A can
detect whether an SRQ has taken place on the bus
by analyzing bit
1
(Register 4 on the 9826A H P-1 B interface - see
table 1 ). Two methods are available for analyzing
the status of the HP-IB interface of the 9826A.
periodically read the interrupt status register
(Register 4). 2) enable the bit 1 of the Interrupt
Enable Mask (Register 5) to interrupt the program
when bit is set. In either case, the user must
1
determine which device on the bus requested ser­
vice. This can be done using an SPOLL command
to sequentially analyze the status byte of each
instrument on the bus. By definition of the IEEE-
488 bus, the instrument that requested service will
have bit 6 of its status byte (REQUEST SERVICE)
true. Once it is determined that the 8340A has
requested service, the specific error condition(s) is
then determined by analyzing the Status Bytes of
the 8340A. The 8340A has two Status Bytes, each
consisting of 8 bits with each bit indicating the pre­
sent status of a particular function or condition.
See table 2 for a complete description of the con­
ditions associated with each status byte bit. The
user can analyze all of the conditions of the status
bytes for every SRQ, or more simply, instruct the
8340A to issue an SRQ only if a specific set of error
conditions exists. The set of error conditions is
determined by a numeric value generated by sum­
ming the decimal values of each bit to be checked
in the first Status Byte. Its binary equivalent is sent
to the 8340A using the Request Mask function
(RM) and CHR$.
The following program demonstrates the capability
of the SRQ and the two Status Bytes to detect an
error condition. This specific example analyzes an
SRQ on an unleveled power condition, an RF
unlocked condition and a front panel service
request when the instrument is in local mode.
13
Using Service
7:
9826A by
of its interrupt status register
1)