Rohde & Schwarz R&S UPP, User Manual

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Remote Control - Fundamentals
R&S
®
UPP
678 User Manual 1411.1055.32 ─ 10
DoEvents
EventList.AddItem "sending INIT command ..."
DoEvents
StartT = Timer
Call ibwrt(UPV, "INIT;*OPC") 'trigger measurement, rise OPC when ready
EventList.AddItem "waiting for SRQ ..."
EventList.AddItem "------------------------------------------------------"
DoEvents
'here the program could do anything else until a SRQ is set
End Sub
6.8.12.3 Parallel Poll
In the case of a parallel poll up to eight devices are simultaneously requested by a
command from the controller to transmit one bit of information on the data lines, i.e. to
set the data line assigned to each device to logic 0 or 1. Analogously to the SRE regis-
ter, which determines the conditions for generating an SRQ, a parallel poll enable
(PPE) register is present that is ANDed bit-by-bit with the STB (taking into account bit
6). The results are ORed and the result is then sent (possibly inverted) to the controller
as a response to a parallel poll. The result can also be read without a parallel poll by
the command
*IST?
.
The device must first be set for parallel poll by the Visual Basic command IBPPC().
This command assigns the device a data line and specifies whether the response is to
be inverted. The parallel poll itself is performed with IBRPP().
The parallel poll mode is mainly used to quickly find out which of the many devices
connected to the IEC/IEEE bus or LAN/USB caused an SRQ. For this purpose, SRE
and PPE must be set to the same value.
6.8.12.4 Queries
Each part of a status register can be read out by queries. The queries are given in the
description of the status commands (STATus subsystem). The queries always yield a
number representing the bit pattern of the queried register. This number is evaluated
by the controller program.
Queries are mainly used after the appearance of an SRQ to obtain more information
about the cause of the SRQ.
Status Reporting System