HP 8508A - Page 56

~ Operation
<a>
SYSTEMS
Enabling Service Requests
The service request enabling operation is shown in Figure 3-24. The user can set bits in the Service Request Enable
Register (SRER). These bits correspond to bits in the Status Byte. If a bit is set in the SRER, it enables the
instrument’s ability to generate an SRQ when the corresponding event occurs. For example, setting bit 4 in the
SRER will produce a service request when the MAV bit is set . _
If a bit is set in the Status Byte, but not enabled in the SRER it cannot cause bit 6 to be set and ponsecqueatly will
not initiate an SRQ, aiheuEh it will be read when the Status Byte is read.
Refer to Figure 3-23 for an example of SRO enabling and handling.
|
|
a
a
|
a
&
a
10
!
HP8508A
Example
HP-IB
SRQ
Enable
&
Handling
Program
;
2
20 !
30 ! This program continually sends an illegal command to the 8508A,
35
!
and
deals
with
the
returned
SRQ.
It
also
reports
the
8508A
a
37 ! going out of tock, when the A channel signal is removed.
40 !
50
Addr=708
!
Vector
Voltmeter
Address
@
60 ON ENTR 7 CALL Intr7 ! Set up SRQ interrupt handler call
7
6
a
80
CLEAR
Addr
!
Clear
interface
:
90
OUTPUT
Addr;‘’*RST;*CLS’’
!
Reset
Vector
Voltmeter
w
100 «|!
110 = OUTPUT Addr; '/*ESE 36" ! Enable SRQ on Query or Command Error
140 3
150 OUTPUT Addr;’’STATUS:OPER:PTR 4" ! Enable SRQ when 8508A becomes
180 OUTPUT Addr;’'STATUS:OPERSENAB 4" ! Unlocked &
200—Cot
210 OUTPUT Addr;:’‘*SRE 160" ! Generate SRQ on above conditions
2301
.
|
|
240 ENABLE INTR 7;2 ! Enable SRQ interrupts in BASIC
250 REPEAT |
260 OUTPUT Addr’ *SYST:KET 1# ! An incorrect Command to generate an SRQ
270 WAIT .5
280 = UNTIL 1=0 ! Repeat Forever |
290 = =END
300!
310! a
320
4
8=6SUB
Intr7
|
330 ‘ DIM Err_message$(100}
340 Addr=708
350 OUTPUT Addr; **STB2!? |
360 ENTER Addr;Stat ! Read Status Byte
370 IF BIT(Stat,5) THEN ||
380 OUTPUT Addr; ''*ESR?"" ! Read & Clear Standard Event Register
390 ENTER Addr; Std_event :
400 IF BIT(Std_event,5) THEN PRINT * ‘Command Error’! |
410 IF BIT(Std_event,2) THEN PRINT ‘*Query Error!’
420 OUTPUT Addr; ‘’SYST:ERR?! ’ B
430_ ENTER Addr ;Err_messageS
440 PRINT Err_messageS
450 END IF a
Ss
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