Status Bit; Abort (Unterface Clear); Addressing - HP 3456A Operating And Service Manual

Model 3456A
happen, refer the ins(rument to a Service Trained
o
Person.
3. Syntax Error. A Syntax Error is when invalid pro­
grams codes are sent to the 3456A. An invalid pro­
gram code is F9.
f. Program Memory Error. This error occurs under
the following two conditions.
I . When trying to execute the program memory Crom
memory (program codes X I in program memory)
and when enabling the Internal Test Crom memory
(program codes TEI in memory). Both conditions
terminate the Program Memory Operation.
2. When exceeding internal memory space during
program memory loading (storing more than 1400
bytes into memory).
g. Limits Failure. A Limits Failure occurs when a
limit is exceeded in the 3456A's Pass/Fail math opera­
tion. More information on the Pass/Fail feature is in
Paragraph 3-81.
3-142. The Status Byte Message in Figure 3-10 is
represented in octal code. Each bit, except for bit 6, in­
dicates a particular Require Service condition. Bit 6
(seventh bit) is the Service Request bit and is true when
service is required. The bit lets the controller know that
a Require Service condition exists. Remember, set the
SRQ mask to output the Require Service Message.
3-143. IC the SRQ mask has been set for more than one
condition, more than one bit of the Status Byte Message
may be true. For example:
a. A Require Service condition sets bits I , 2, and 6
true. (Remember, bit 6 is true for any Require Service.)
The conditions are caused by Program Memory Execu­
tion Complete and Data Ready.
b . The Status Byte looks like:
b7
A "1"
in this example indicates a true condi­
tion.
Program Memory Error
Illegal Instrument State
b0
NOTE
limits Failure
Service Request
}
Internal Error
Syntax Error
c. The byte is output in octal code and the correspon­
ding octal number is:
The resultant decimal number oC octal 106 is 70.
3·1 44. Status Bit.
3-145. The 3456A does not respond to a Parallel Poll.
The Status Bit i s not part o f the Status Byte
Message and should not be confused with
the bits in the Status Byte Message.
3·146. Pass Control.
3-147. The 3456A does not have controller capabilities.
3·148. Abort Unterface Clear).
3-149. All HP-IB communication is terminated, in­
cluding the 3456A's Bus communication. Control is
returned to the system controller. The Abort Message
does not remove the 3456A Crom remote control.
3·150. 3456A Addressing.
3-151. HP-IB requires that a device on the Bus needs to
be identiCied as a Listener or a Talker, in order to ex­
ecute the Bus Messages and commands. Because of this
requirement, each device on the HP-IB has a unique
"listen" and "talk"address to distinguish themselves
from each other. The device is then able to receive pro­
gramming instructions when addressed to listen or sent
data when addressed to talk.
3-152. The 3456A's address is set by the address switch
located at the instrument's rear panel. The switch is a
seven section
address selection, as shown in Table 3-8. The sixth
switch is not used and the seventh switch sets the instru­
ment to the "Talk-Only" mode (see Paragraph 3-154).
The 3456A's allowable address settings are listed in
Table 3-8. Its Cactory address setting is a listen address
of 22 decimal (ASCII character "6") and a talk address
of 54 decimal (character "V")
bO
b1
Front Panel SRC
Program Memory Execution Complete
Data Ready
Trigger Too Fast
Figure 3·10. Status Byte.
01 000 1 10
L�3
NOTE
"mp"
switch with five switches used for
Operation
3-21