Annex
NRP2
356
User Manual 1173.9140.02 ─ 07
–
SRQ
(Service Request):
Active LOW enables a device to send a service request to the controller.
–
REN
(Remote Enable):
Active LOW permits switchover to remote control.
–
EOI
(End or Identify):
Has two functions in connection with ATN:
ATN = HIGH: active LOW marks the end of data transmission
ATN = LOW: active LOW triggers a parallel poll.
●
Handshake bus with three lines:
–
DAV
(Data Valid):
Active LOW signals a valid data byte on the data bus.
–
NRFD
(Not Ready For Data):
Active LOW signals that one of the connected devices is not ready for data
transfer.
–
NDAC
(Not Data Accepted):
Active LOW until the connected device has accepted the data on the bus.
A.2.1.4
GPIB bus interface
Instruments which can be controlled via GPIB bus can be equipped with different inter-
face functions. The interface function for the R&S
NRP2 are listed in the following
table.
Table 1-1: GPIB bus interface functions
Control
character
Interface function
SH1
Source handshake
AH1
Acceptor handshake
L3
Listener function, Listen-Only mode, unaddressed for MSA and TPAS, recognizes END and
EOS.
LE3
Extended Listener function, Listen-Only mode, unaddressed for MSA and TPAS, recogni-
zes END and EOS.
T5
Talker function, capability to respond to serial poll, Talk-Only mode, unaddressed on MLA,
sends END or EOS.
TE5
Extended talker function, capability to respond to serial poll, Talk-Only mode, unaddressed
for MLA and LPAS, sends END or EOS.
SR1
Service request function
PP1
Remote parallel-poll function
PP2
Local parallel-poll function
RL1
Remote/local switchover function
DC1
Device clear
E2
3-state driver (open-collector driver during parallel poll)
Remote control interfaces
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