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Remote Operation via HP-iB
Clear Lockout/Set Local
The clear lockout/set local command removes all devices from the local lockout mode and
If
^
control. The HP-IB is in the local mode because
the
bus management line is set false.
Local
The /oca/ command clears the remote command from the listening device ariH returns the
listening device to local (front panel) control. If local lockout is not in effect, the HP 3325B
responds by returni^ to front panel control. The Remote indicator on the front panel
extinguishes if the HP 3325B is in Remote prior to the Local command.
Local Lockout
command disables the Local front panel key to avoid operator interference.
1 he HP 3S25B front panel is locked out.
Parallel Poll
The para//e/po// command is a controller operation used to obtain information from the
devices under its control. The HP 3325B does not respond to this bus command.
Pass Control
Sfcommand shifts system control from one controller to another. The
xlr
ooZdB
does not respond to this command.
Remote
The remote
command directs an instrument to take instructions from the HP-IB instead of
lu
®
panel. To implement the remote command, the controller must set
the REN bus management line true. When the HP 3325B accepts the remote command, the
^mote front panel indicator illuminates and the front panel is disabled except for the Local
key which can return control of the instrument to the front panel if pressed. If the
local
/oc^oat message is also issued, the mode cannot be changed from remote to local via the front
panel LLocalj key.
Serial Poll
The
IS issued by the active controller along with a specific address. If the address
matches
the
address setting of the HP 3325B, it responds by putting its status byte on the
toa lines for the controller to read. The HP 3325B status b
3
rte consists of eight bits
indicating the states of several operating parameters (refer to "The Status B
3
d:e").
Service Request
The
sejvice request
(SRQ) bus management line is used by a device to indicate a need for
attention from th^e controller. When the HP 3325B requires service (as is determined by the
" SRQ (pulls the SRQ line low), sets bit 6 of the
status b^e (see the
Status Byte ), and illuminates the front panel SRQ indicator. The SRO
IS cleared by executing a serial poll of the HP 3325B. Bit 6. the require-?ervice bit is
^
sometimes referred to as the status bit in connection with a poll. Bits 0,1, 2, and 3 in the
^atus byte may initiate an SRQ, depending on the setting of the status byte mask.
Ihe status b^e may be masked to select which of the four bits cause the HP 3325B
to issue the SRQ.
2-8
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