General; Computer Interface Operation; Ieee-488 Interface; Chapter 6 6.1 General - Lakeshore 335 User Manual

Chapter 6: Computer Interface

6.1 General

6.2 IEEE-488
Interface
Operation
This chapter provides operational instructions for the computer interface for the
Lake Shore Model 335 temperature controller. Both of the computer interfaces pro-
vided with the Model 335 permit remote operation. The first is the IEEE-488 interface
described in section 6.2. The second is the USB interface described in section 6.3. The
two interfaces share a common set of commands detailed in section 6.4. Only one of
the interfaces can be used at a time.
The IEEE-488 interface is an instrumentation bus with hardware and programming
standards that simplify instrument interfacing. The Model 335 IEEE-488 interface
complies with the IEEE-488.2 standard and incorporates its functional, electrical,
and mechanical specifications unless otherwise specified in this manual.
All instruments on the interface bus perform one or more of the interface functions of
Talker, Listener, or Bus Controller. A Talker transmits data onto the bus to other
devices. A Listener receives data from other devices through the bus. The Bus Control-
ler designates to the devices on the bus which function to perform. The Model 335
performs the functions of Talker and Listener, but it cannot be a Bus Controller. The
Bus Controller is the digital computer that tells the Model 335 which functions to
perform.
TABLE 6-1 defines the IEEE-488 capabilities and subsets for the Model 335:
Subset Capabilities
SH1 Source handshake capability
RL1 Complete remote/local capability
DC1 Full device clear capability
DT0 No device trigger capability
C0 No system controller capability
Basic Talker, serial poll capability, talk only,
T5
unaddressed to talk if addressed to listen
Basic Listener, unaddressed to listen if
L4
addressed to talk
SR1 Service request capability
AH1 Acceptor handshake capability
PP0 No parallel poll capability
E1 Open collector electronics
TABLE 6-1 Model 335 IEEE-488 interface capabilities
and their subsets
Instruments are connected to the IEEE-488 bus by a 24-conductor connector cable as
specified by the standard (section 8.10.1). Cables can be ordered from Lake Shore as
IEEE-488 Cable Kit 4005, or they can be purchased from other electronic suppliers.
Cable lengths are limited to 2 m (6.6 ft) for each device and 20 m (65.6 ft) for the
entire bus. The Model 335 can drive a bus with up to ten loads. If more instruments or
cable length is required, a bus expander must be used.
6.1 General 89
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