Hp-Ib Implementation On The 7470; Interface Switches And Controls; Addressing The Plotter - HP 7470A Interfacing And Programming Manual

HP—IB Implementation on the 7470
The HP—IB conforms to ANSI/IEEE 488-1978specifications, and direct
interconnection of the HP—IB is via a connector on the rear panel.
The HP—IB functions implemented in the 7470 are as follows:
1. Source Handshake (SH1)
Acceptor Handshake (AH1)
Talker (T2)
Listener (L2)
Service Request (SR1)
No Remote Local (RLO)
Parallel Poll (PPOif lon; PP2 if addr <8; PPO otherwise)
Device Clear (DC1)
N0 Device Trigger (DTO)
No Controller (C0)
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Interface Switches and Controls
The 7470 plotter functions in either of two modes, addressable mode
and listen-only mode. In addressable mode, the plotter can function as
a talker or as a listener depending on the instructions it receives from
the controller. In listen-only mode, it can only listen and it hears all
activity on the bus.
Addressing the Plotter
Rear panel switches provide for selection of the plotter address or listen­
only mode. Each HP—IB interface can have as many as 15 devices con­
nected to it, set to different specific address codes. The plotter can be set
to any one of 31 HP—IBaddresses, ranging from 0 through 30. Each
address can be selected by setting the switches on the rear panel to the
appropriate binary bit positions for the particular address value desired.
The address selected establishes the 7470'sdevice address. When using
the plotter with an HP desktop computer, do not use 21 which is
reserved for the desktop computer's address. When not using an HP
desktop computer, be sure the computer and plotter do not have the
same address. (Refer to the documentation for your computer.) Address
31 is used to set the plotter to listen-only mode.
The plotter is set to an address code of 05 at the factory. This corres­
ponds to a listen character of % and a talk character of E. Check the
following figure for the factory—set a ddress switch positions.
9-2 HP—IB INTERFACING