Gpib Connector; Gpib Address - Extech Instruments 7470 Operation Manual

Interface Management Lines: Five lines are used to manage the flow of information
across the interface.
ATN (attention) ATN is driven true by the controller when it uses the data lines to send
commands, and drivers ATN false when a Talker can send data messages.
IFC (interface clear) IFC is driven by the system controller to initialize the bus and
become CIC.
REN (remote enable) The REN line is driven by the controller that is used to place
devices in remote or local program mode.
SRQ (service request) The SRQ line can be driven by any device to asynchronously
request service from the Controller.
EOI (end or identify) This line has two purposes- the Talker uses this line to mark the
end of a message string, and the Controller uses it to tell devices to identify their
response in a parallel poll.

9.4. GPIB Connector

Connection is usually accomplished with a 24-conductor cable with a plug on one end
and a connector at the other end. Devices may be connected in a linear, star or a
combination configuration.
The standard connector is the Amphenol or Cinch Series 57 Microribbon or AMP
CHAMP type. The GPIB uses negative logic with standard transistor-transistor logic
(TTL) levels. When DAV is true, for example, it is a TTL low level ( 0/8 V), and when
DAV is false, it is a TTL high level ( 2.0 V).
Restrictions and Limitations on the GPIB
A maximum separation of 4 m between any two devices and an average separation of
2 m over the entire bus. A maximum total cable length of 20 m.
No more than 15 device loads connected to each bus, with no less than two-thirds
powered on. For example 1 GPIB controller and a maximum of 14 GPIB instruments.
Note: A bus extender, which is available from numerous manufacturers, is available
to overcome these limitations.

9.5. GPIB Address

This interface is optional on the High Withstand Voltage Tester. Each device on the
GPIB (IEEE-488) interface must have a unique address. You can set the address of
the High Withstand Voltage Tester to any value between 0 and 30. The address is set
to 8 when the instrument is shipped from the factory. The address can only be set
from the front panel. The address is stored in non-volatile memory and does not
change when the power has been off or after a remote reset.
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