F-4
IEEE-488 Bus Overview
A device is placed in the talk or listen state by sending an appropriate talk or listen command.
These talk and listen commands are derived from an instrument’s primary address. The primary
address may have any value between 0 and 31, and is generally set by rear panel DIP switches
or programmed in from the front panel of the instrument. The actual listen address value sent
out over the bus is obtained by ORing the primary address with $20. For example, if the primary
address is $7, the actual listen address is $27 ($27 = $7 + $20). In a similar manner, the talk
address is obtained by ORing the primary address with $40. With the present example, the talk
address derived from a primary address of $7 would be $47 ($47 = $7 + $40).
The IEEE-488 standards also include another addressing mode called secondary addressing.
Secondary addresses lie in the range of $60-$7F. Note, however, that many devices, including
the Model 2182, do not use secondary addressing.
Once a device is addressed to talk or listen, the appropriate bus transactions take place. For
example, if the instrument is addressed to talk, it places its data string on the bus one byte at a
time. The controller reads the information, and the appropriate software can be used to direct the
information to the desired location.
Bus lines
The signal lines on the IEEE-488 bus are grouped into three different categories: data lines,
management lines, and handshake lines. The data lines handle bus data and commands, while
the management and handshake lines ensure that proper data transfer and operation takes place.
Each bus line is active low, with approximately zero volts representing a logic 1 (true). The
following paragraphs describe the operation of these lines.
Data lines
The IEEE-488 bus uses eight data lines that transfer data one byte at a time. DIO1 (Data
Input/Output) through DIO8 (Data Input/Output) are the eight data lines used to transmit both
data and multiline commands and are bi-directional. The data lines operate with low true logic.
Bus management lines
The five bus management lines help to ensure proper interface control and management.
These lines are used to send the uniline commands.
ATN (Attention) — The ATN state determines how information on the data bus is to be
interpreted.
IFC (Interface Clear) — The IFC line controls clearing of instruments from the bus.
REN (Remote Enable) —The REN line is used to place the instrument on the bus in the
remote mode.
Summary of Contents for 2182
Page 1: ...www tek com keithley Model 2182 2182A Nanovoltmeter User s Manual 2182A 900 01 Rev B May 2017...
Page 18: ......
Page 22: ......
Page 23: ...1 Getting Started Getting Started...
Page 41: ...2 VoltageandTemperature Measurements Voltageand Temperature Measurements...
Page 68: ...2 28 Voltage and Temperature Measurements...
Page 69: ...3 Range Digits Rate andFilter Range Digits Rate andFilter...
Page 82: ...3 14 Range Digits Rate and Filter...
Page 83: ...4 Relative mX b and Percent Relative mX b andPercent...
Page 91: ...5 RatioandDelta Ratioand Delta...
Page 117: ...6 Buffer Buffer...
Page 123: ...7 Triggering Triggering...
Page 140: ...7 18 Triggering...
Page 141: ...8 Limits Limits...
Page 149: ...9 SteppingandScanning Steppingand Scanning...
Page 168: ...9 20 Stepping and Scanning...
Page 169: ...10 AnalogOutput Analog Output...
Page 175: ...11 RemoteOperation Remote Operation...
Page 205: ...12 CommonCommands Common Commands...
Page 221: ...13 SCPISignalOriented Measurement Commands SCPISignalOri entedMeasure ment Commands...
Page 225: ...14 SCPIReferenceTables SCPIRefer enceTables...
Page 239: ...15 AdditionalSCPI Commands Additional SCPICom mands...
Page 260: ...15 22 Additional SCPI Commands...
Page 261: ...A Specifications Specifications...
Page 263: ...B Statusand ErrorMessages StatusandError Messages...
Page 268: ...B 6 Status and Error Messages...
Page 269: ...C Measurement Considerations Measurement Consider ations...
Page 278: ...C 10 Measurement Considerations...
Page 279: ...D Model182Emulation Commands Model182 EmulationCom mands...
Page 284: ...D 6 Model 182 Emulation Commands...
Page 285: ...E Example Programs ExamplePro grams...
Page 293: ...F IEEE 488 BusOverview IEEE 488Bus Overview...
Page 307: ...G IEEE 488andSCPI ConformanceInformation IEEE 488and SCPIConform anceInforma tion...
Page 310: ...G 4 IEEE 488 and SCPI Conformance Information...
Page 311: ...H Measurement Queries Measurement Queries...
Page 316: ...H 6 Measurement Queries...
Page 317: ...I Delta PulseDelta and DifferentialConductance Delta Pulse Deltaand Dif ferentialCon ductance...
