Table of Contents
Advertisement
IEEE 488 Introduction
measure a resulting parameter. Thus the intelligence of IEEE
devices can be exploited to a great extent.
______________________ _
Remote - Local Functions.
The remote and local functions are used to place the IEEE
device under remote control via the PSI BOX or under local
control via its front panel switches.
The Remote command is used to make the controller assert
the REN line, remote enable, so allowing the bus devices to
respond to the PSI BOX. If the REN line is not asserted the bus
device will not respond to the PSI BOX, they will ignore the
PSI BOX.
Even when the bus devices are under PSI BOX remote
control if you press the devices front panel "LOCAL" button it
will return to local control unless it has been put into the
LOCAL LOCKOUT state.
Whenever a read or write is performed or whenever any
bus command is sent the PSI BOX reasserts the REN line.
The GTL, Go To Local, and Local commands are used to
tell all the currently listening devices to respond to their front
panel, local, controls rather than to the PSI BOX.
The Local Lockout command is used to tell all the bus
devices to ignore their front panel, local, controls and respond
only to the IEEE controller. This is necessary when you want
the instrument to be totally under the control of the PSI BOX. It
prevents accidental pushing of the devices buttons interfering
with its operation.
The device will return to local control when it receives the
LOCAL or GTL command, or when the IEEE REN line goes
false.
__________________________ _
End Of Sequence Termination,
How do IEEE devices know that they have received all the
Chapter 2
PSI BOX Reference
Page 23
Advertisement
Table of Contents
