I
-
I
-
Front/Rear Panel
Connectors
As many as 14
HP-h3
instruments can be connected to the analyzer
(15 total instruments in the system). The cables can be interconnected in
a star pattern (one central instrument with the HP-IB cables emanating
from that instrument like spokes on a wheel), or in a linear pattern (like
boxcars on a tram), or a combination of the two. See Figure
l-5
in Chapter 1.
There are certain restrictions that must be followed when interconnecting
instruments:
l
Each instrument must have a unique HP-IB address, ranging from 0 to 30.
l
In a two-instrument system that uses just one HP-IB cable, the cable length
must not exceed 4 meters (13.2 ft).
l
When more than two instruments are connected on the bus, the cable
length to each instrument must not exceed two meters (6.6 ft).
l
The total cable length between all instruments must not exceed 20 meters
(66 ft).
Hewlett-Packard manufactures HP-IB extender instruments (Models
HP
37204A)
and HP
37204B)
that overcome the range limitations imposed by
the cabling rules. These extenders allow twin pair cable operation up to 1 km
(3,280
ft),
and telephone modem operation over any distance. HP Sales and
Service Offices can provide additional information on the HP-IB extenders.
Table
8-l.
General Bus Management lines
Name
Attention
Interface Clear
Mnemonic
ATN
IFC
Description
Controls whether the bus is in Command Mode
lATN
TRUE1
or Data Mode
IATN
FALSEI.
Initializes the interface to en idle state lno activity on the
bus).
Service Request
SKI
Remote Enable
REN
Alerts the Controller to a need for communication.
Enables devices to respond to Remote Program Control when addressed
to listen.
End Or Identify
EOI
Indicates last data byte of a multibyte sequence; also used with ATN to parallel
poll devices for their status bit.
8-8
-1
深圳市盛腾仪器仪表有限公司 Tel:0755-83589391 Fax:0755-83539691 Website: www.Sengt.com
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