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Installation and Configuration
High-Speed Configuration
To achieve the maximum possible data transfer rate within a system, the
following guidelines must be followed:
I.
Switch
51(7),
marked "SLOW", should be set to the high speed position (down
or closed). Switch S I (7) determines the delay between data assertion and
DA V (data valid) during an HP-IB write from the computer to the device.
With the switch in SLOW position (up or open) a delay of approximately 500
nsec is realized. In the high-speed (down) position, the delay is reduced to
approximately 350 nsec.
2.
All devices expected to talk at high speed must use a settling time of 350
nanoseconds or more.
3.
All devices expected to talk at the higher rates should use 48 rnA, tri-state
drivers.
4.
The device capacitance on each HP-IB line, except REN (Remote Enable)
and IFC (Interface Clear), should be less than 50 pF per device. In a system
configuration, the total device capacitance should be no more than 50 pF for
each equivalent resistive load in the system.
5.
Interconnecting cable links should be as short as possible, with a maximum of
15 metres total length per system (see table 3-1). There should be AT LEAST
one equivalent resistive load per metre (3.28 ft) of cable. With the HP-IB
Channel Card as the System Controller, each peripheral device provides a
resistive load, and the high-speed resistor pack adds seven equivalent resistive
loads.
Table 3-1. Maximum HP-IB Cable Lengths
Number of
Peripheral Devices
1
.... plus
7
2
3
4
5
6
7
8
(maximum)
resistive
Maximum Total
Cable Length (metres)
loads .... 8
9
10
11
12
13
14
15
A maximum system would therefore be composed of the HP-IB card as the
System Controller (with its high-speed resistor pack installed) and eight HP-IB
peripherals.
.
3-3
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