HP 3478A Technical Manual page 120

3478A 3478A
b. b. Listener: Devices which receive information Listener : Devices which receive information
over the HP-IB, when they have been ad over the HP-IB, wh en they have been addressed.
device may or may not be both a talker and a listener. device may or may not be both a talker and a
Calculators and computers are generally both a talker and Calculators and computers are generally both a talker and
a listener (at different times). a listener (at different times).
c. c. Controller Controller: The device that can specify which : The device that can specify which
device(s) on the bus is a talker or liste device(s) on the bus is a talker or listener.
two types of controllers, an Active Controller and a System two types of controllers, an Active Controller and a System
Controller. Controller. The Active Controller The Active Controller is the current con
device. device. The System Contr The System Controller can, however, t
of the HP-IB even if it is not the Ac of the HP-IB even if it is not the Active Controller.
can also be only one Active Controller at a time, even if can also be only one Active Controller at a
several controllers are on the Bus. several controllers are on the Bus.
A-14. A-14. HP-IB HP-IB Messages Messages
A-15 A- 15. . Di Diff ffer eren ent t t typ ypes es of of in info form
over the HP-IB to one or more dev over the HP-IB to one or more devices.
information is in the form of messages, most of which can information is in the form of messages, most of which can
be separated into two parts. be separated into t wo parts. One part can be c
the address portion specified by the controller and the the address portion specified by the controller and the
information that comprises the mess information that c omprises the messages.
part can be classified as HP-IB management messages. part can be classified as HP-IB management messages.
These message are comprised of twelve messages and These message are comprised of twelve
are called Bus messages. are called Bus messages.
a. a. Data Data: The actual information (binary bytes) sent : The actual information (binary bytes) sent
Figure A-1. Interface Connection Figure A-1. Interface Connection and Bus Structure
dressed. A A
listener.
ner. There can be There can be
is the current controlling
oller can, however, take control ake control
tive Controller. There
time, even if
rmat atio ion c n can an be be pa pass ssed
ices. Some of this Some of this
One part can be classified as lassified as
ages. The second The second
messages and
and Bus Structure
by a talker to one or more listener by a talker to
can either be in numeric form or a character string. can either be in numeric form or a character string.
b. b.
listening device or devices to perform a device dependent listening device or devices to perform a device dependent
action when addressed. action when addressed.
c. c.
device(s) or all the devices on the HP-IB to return to their device(s) or all the devices on the HP-IB to return to their
trolling predefined device-dependent state. predefined device-dependent state.
There d. d.
device(s) to switch from local front panel control to remote device(s) to switch from local front
program control when addressed to listen. program control when addressed to listen.
e. e.
message from the listening device(s) and returns the message from the listening device(s) and returns the
ed
device(s) to local front panel device(s) to local front panel control.
f. f.
device operator from manually inhibiting remote program device operator from manually inhibiting remote program
control. control.
g. g.
message, all devices are removed from the local lockout message, all devices are removed from the local lockout
mode and revert mode and revert to local.
cleared for all devices. cleared for all devices.
A-2 A-2
one or more listener. . The information (dat
Trigger: The Trigger message causes the Trigger : The Trigger message causes the
Clear: The Clear message causes the listening Clear : The Clear message causes the listening
Remote: This message causes the listening Remote : This message causes the listening
Local Local: This message clears the REMOTE : This message clears the REMOTE
control.
Local Lockout Local Lockout: This message prevents a : This message prevents a
Clear Lockout and Set Local: With this Clear Lockout and Set Local
to local. The remote mess The remote message is also
TM 11-6625-3071-14 TM 11-6625-3071-14
The information (data) a)
panel control to remote
: With this
age is also