HP 8112A Operating, Programming And Servicing Manual page 90

Terminators
Note
Possible Problem with
Programming
6-20
HP 8 1 1 2As with the new firmware (starting with serial number
2851 G07381 ) work correctly with the terminators listed on page
3. Devices with older firmware will hang up when receiving both
CR/LF and EOI. Therefore termination with both CR/LF and EOI
should be avoided when programming devices with old fi r mware.
Since some controllers cannot (easily) be configured so that they do
not to use CR/LF and EOI
devices is disconnected.
Users of some non-HP versions of BASIC may experience difficulty in
terminating with CRLF alone, i .e. EOI cannot easily be turned off.
If this is the case, a jumper setting inside the instrument allows EOI
line to be ignored. To set this jumper proceed as follows:
•
Remove rear feet and top cover
•
Transfer jumper A3W3 at the center of the microprocessor board
A3 from the factory setting
The HP 81 12A (with old and new firmware) does not pull the EOI
line. The device terminates all messages with CR/LF and a space
character.
If the HP 81 12A is the only instrument on the bus, the SPOLL
statement may cause the instrument to "hang up" .
SPOLL
Either of the following will clear the fault :
1 . Use an HP-IB cable of not less than 2m length. Or:
2. Use a user-defined function to interrogate the status byte instead
of the usual SPOLL statement .
In the following program, line 20 causes a syntax error so that a
SRQ is generated. Lines 40 to 1 30 show how the status byte can be
interrogated with a user-defined function:
10
20
OUTPUT A ; " XYZ "
30
40
50 END
60
DEF FNSpol l (A)
70
H_ addr = A MOD 100
80
90
SEND S_code ; UNL MLA TALK H_addr CMD
100 ENTER S_ code USING " # , B " ; Stb
1 10 SEND S_ code ; CMD 25 UNT
120 RETURN Stb
130 FNEND
as
A = 712
WAIT . 05
PRINT "Status byte : " , FNSpoll (A)
S_ code = A DIV 100
terminator, the EOI line of some older
3.
to position
EOI
24