Ieee-488 Function Subsets; Srq Using - Newport LDS1000 User Manual

LDS1000
EDH0170FE1010 – 09/98
B.2

IEEE-488 Function Subsets

This controller support the many GPIB function subsets, as listed bellow.
Some of the listings described subsets that the controller does not support.
C0 (Controller). The LDS1000 can not control other devices.
T5 (Talker). The LDS1000 becomes a Talker when the CIC (Controller In
Charge) sends its TAD (Talker Address) with the ATN (Attention) line
asserted. It ceases to be a talker when the CIC (Controller In Charge) sends
another device's TAD (Talker Address) with ATN (Attention) asserted.
L4 (Listener). The LDS1000 becomes Listener when the CIC (Controller In
Charge) sends its LAD (Listener Address) with the ATN line asserted. The
LDS1000 does not have Listen Only capability.
SH1 (Source Handshake). The LDS1000 can transmit multiline messages
accros the GPIB.
AH1 (Acceptor Handshake). The LDS1000 can receive multiline messages
accros the GPIB.
SR1 (Service Request). The LDS1000 asserts SRQ (Serial Request) line to
notify the CIC ( controller In Charge ) when it requires service.
RL0 (Remote / Local). The LDS1000 does not support the GTL (Go To
Local) and LLO (Local Lock Out) functions.
PP0 (Parralel Poll). The LDS1000 has no Parallel Poll capability. It does not
respond to the following interface messages: PPC, PPD, PPE and PPU. The
LDS1000 does not send out a message when the ATN (Attention) and EOI
(End or Identify) line are asserted.
DC1 (Device Clear). The LDS1000 responds to the DCL (Device Clear) and,
when made Listener, the SDC (Selected Device Clear) interface message.
DT0 (Device Trigger). The LDS1000 does not support GET (Group Execute
Trigger) interface message.
E2 (Electrical). The LDS1000 uses tristate buffers to provide optimal high-
speed data transfer.
B.3

SRQ Using

The NI488.2 User Manual for Windows from National Instruments, in the
GPIB Programming Techniques chapter describes the use of Serial Polling
as follow (page 7-5):
Serial Polling
You can use serial polling to obtain specific information from GPIB devices
when they request service. When the GPIB SRQ line is asserted, it signals
the Controller that a service request is pending. The controller must then
determine which device asserted the SRQ line and respond accordingly.
The most common method for SRQ detection and servicing is serial poll.
This section describes how you can set up your application to detect and
respond to service requests from GPIB devices.
Service Requests from IEEE-488 Devices
IEEE-488 devices request service from the GPIB Controller by asserting the
GPIB SRQ line. When the Controller acknowledge the SRQ, it serial polls
each open device on the bus to determine which device requested service.
Any device requesting service returns a status byte with bit 6 set and then
unasserts the SRQ line. Devices not requesting service return a status byte
with bit 6 cleared. Manufacturers of IEEE-488 devices use lower order bits
to communicate the reason for the service request or to summarize the
state of the device.
Controller for Laser Diode Sensors
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