YOKOGAWA WE7281 User manual

User's
Manual
IM 707281-01E
2nd Edition
IM 707281-01E
2nd Edition
4-CH, 100 kS/s D/A Module

1
IM 707281-01E
Disk No. WE09
2nd Edition: August 2000 (YK)
All Rights Reserved, Copyright © 1999 Yokogawa Electric Corporation
Thank you for purchasing the 4-CH, 100 kS/s D/A Module WE7281/WE7282 for the PC-
based measurement instrument, WE7000.
This User’s Manual contains useful information about the function, connection to the
measuring station, operations of the software on the PC, and troubleshooting of the
WE7281/WE7282. This manual assumes that you will be using the WE7000 Control
Software that is included with the measuring station.
For general information about the WE7000 (primarily the operations of the measuring
station, the optical interface module, the optical interface card, and the WE7000 Control
Software) see the following manual that is included with the measuring station.
Manual Title Manual No.
WE7000 User’s Manual IM707001-01E
To ensure correct use, please read this manual thoroughly before operation. Keep this
manual in a safe place for quick reference in the event a question arises.
Notes
•The contents of this manual describe WE7000 Control Software Ver. 4.0.2.0 and
module software Ver. 3.09. If you are using another version of the software, the
operating procedures or the figures given in this manual may differ from the
actual software.
• The figures of operation panels that are used in this manual correspond to WE7281. If
you are using WE7282, WE7282 will be displayed.
• The contents of this manual are subject to change without prior notice as a result of
continuing improvements to the instrument’s performance and functions.
• Every effort has been made in the preparation of this manual to ensure the accuracy
of its contents. However, should you have any questions or find any errors, please
contact your nearest YOKOGAWA dealer.
• Copying or reproducing any or all of the contents of this manual without
YOKOGAWA’s permission is strictly prohibited.
Trademarks
• Microsoft, Windows, and Windows NT are either registered trademarks or trademarks
of Microsoft Corporation in the United States and/or other countries.
• Adobe and Acrobat are trademarks of Adobe Systems Incorporated.
• Other product names are trademarks or registered trademarks of their respective
holders.
Revisions
1st Edition: September 1999
2nd Edition: August 2000

2IM 707281-01E
Checking the Contents of the Package
Unpack the box and check the contents before operating the instrument. If the contents
are not correct or missing or if there is physical damage, contact the dealer from which
you purchased them.
Measurement Module
Check that the model name given on the name plate matches those on the order.
MODEL
Model Description
707281 WE7281 4-CH, 100 kS/s D/A Module
707282 WE7282 4-CH, 100 kS/s D/A Module (BNC output terminals)
NO.
When contacting the dealer from which you purchased the instrument, please quote the
instrument No. The following is an example of WE7281. The name plate is also at the
same position for WE7282.
MODEL
MODEL
NO.
NO.
Made in Japan
Standard Accessories
The following standard accessories are supplied with the instrument. Make sure that all
items are present and undamaged.
User's Manual (1)
IM707281-01E
Terminal block (Model: A1460JT) (1)
(Included only with WE7281, attached to the module)
Optional Accessories (Sold Separately)
Name Model Description
Terminal block A1460JT Clamp type terminal, sold in units of 1 piece
* There are no optional accessories for WE7282.

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IM 707281-01E
How to Use This Manual
Structure of the Manual
This User’s Manual consists of the following five chapters and an index.
Chapter Title Description
1 Explanation of Functions Explains the system configuration and functions.
2 Hardware Preparation Explains how to install the module into the
measuring station and how to connect the input.
3 Software Operation Explains how to operate the software on the PC.
4 Troubleshootingand Maintenance Explains the procedures for
troubleshooting and self testing.
5 Specifications Explains the specifications of the module.
Index Index of contents.
Conventions Used in This Manual
Unit
k ................. Denotes 1000. Example: 100 kHz
K ................. Denotes 1024. Example: 720 KB
Displayed characters
Alphanumeric characters enclosed with [ ] usually refer to characters or settings that are
displayed on the screen.
Symbols
The following symbol marks are used to attract the operator’s attention.
Affixed to the instrument. Indicates danger to personnel or to the
instrument. The operator must refer to the User’s Manual. The
symbol is used in the User’s Manual to indicate the reference.
Warning Describes precautions that should be observed to prevent injury or
death to the user.
Caution Describes precautions that should be observed to prevent minor or
moderate injury, or damage to the instrument.
Note Provides information that is important for operating the instrument
properly.

4IM 707281-01E

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IM 707281-01E
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2
3
4
5
Index
Contents
Checking the Contents of the Package .................................................................................................................... 2
How to Use This Manual .......................................................................................................................................... 3
Chapter 1 Explanation of Functions
1.1 Principles of Waveform Generation ........................................................................................ 1-1
1.2 System Configuration and Block Diagram .............................................................................. 1-2
1.3 Waveforms That Can Be Generated ....................................................................................... 1-3
1.4 Waveform Generation in the DC Mode ................................................................................... 1-4
1.5 Waveform Generation in the AG Mode ................................................................................... 1-5
1.6 Waveform Generation in the FG Mode ................................................................................... 1-8
1.7 Other Functions .................................................................................................................... 1-14
1.8 Names and Functions of Sections ........................................................................................ 1-15
Chapter 2 Hardware Preparation
2.1 Installing the Module into the Measuring Station .................................................................... 2-1
2.2 Connecting the Output Signal Wire ........................................................................................ 2-3
Chapter 3 Software Operation
3.1 Selecting the Waveform Generation Mode ............................................................................. 3-1
3.2 Setting the Output Conditions in the DC Mode ....................................................................... 3-2
3.3 Setting the Output Condition in the AG Mode ......................................................................... 3-4
3.4 Setting the Output Condition in the FG Mode ......................................................................... 3-9
3.5 Turning ON/OFF the Output ................................................................................................. 3-16
Chapter 4 Troubleshooting and Maintenance
4.1 Troubleshooting ...................................................................................................................... 4-1
4.2 Self Test .................................................................................................................................. 4-2
4.3 Maintenance ........................................................................................................................... 4-3
Chapter 5 Specifications
5.1 Performance Specifications .................................................................................................... 5-1
5.2 Default Values (Factory Default Settings) ............................................................................... 5-4
5.3 General Specifications ............................................................................................................ 5-5
5.4 Dimensional Drawings ............................................................................................................ 5-7
Index ................................................................................................................................................ Index-1

1-1
IM 707281-01E
1
Explanation of Functions
Chapter 1 Explanation of Functions
1.1 Principles of Waveform Generation
The 4-CH, 100 kS/s D/AModule WE7281/WE7282 has DC, AG, and FG waveform generation
modes. Of the three modes, the operation principles of AG and FG modes are described here.
AG mode
In the AG mode, waveform data previously written to the waveform memory are read
according to the specified sampling interval and output sequentially (digital synthesis).
As shown in the figure below, the address counter operates based on the clock, which
has a frequency that is the inverse of the sampling interval, and provides addresses to
the waveform memory. Data obtained from the waveform memory of the specified
address are converted to an analog signal by the D/A converter and high frequency
components are removed by the LPF. The data processor inside the module carries out
the address counter operation, the reading of waveform data from the waveform
memory, and the configuration of the waveform output D/A.
Clock
Address
counter Waveform
memory
Waveform
output D/A LPF Waveform
output
FG mode
In the FG mode, waveform is generated using DDS (Direct Digital Synthesis). As shown in
the figure below, DDS is composed of a reference clock signal generator, a phase
computing unit, a waveform memory containing one cycle of waveform data, a D/A
converter, a LPF, and other components. Because the waveform memory only stores the
data for one-cycle of the waveform, the address values correspond to the phase angles of
the waveform.
Phase computing unit
NAdder Latch
Reference clock
Waveform
memory
Waveform
output D/A LPF Waveform
output
If N is one input to the adder and the other input is 0, the adder outputs N. The latching
circuit outputs N in sync with the standard clock. This value, N, will be the first address
of the waveform memory. Next, the N that is output from the latching circuit is input to
the adder which then outputs 2N. The latching circuit outputs 2N in sync with the next
clock cycle. The result is continuously added and the phase computing unit outputs 3N,
4N, and so on, for every clock cycle. These values, N, 2N, 3N, ... become the waveform
memory addresses. The data at the specified address is converted to an analog signal
through the D/A converter, and high frequency components are removed with the LPF.
In this DDS method, If the value N is applied to the input of the phase computing unit
such that the specified address is three greater than the previous address, the output
frequency will be increased by a factor of three if the clock frequency stays the same.
Thus, the output frequency of the waveform can be adjusted by changing the value of N.
Also, by changing the data in the waveform memory, the circuit can output other wave-
forms such as triangular and pulse waveforms that are provided by the module as well
as arbitrary waveforms that are loaded externally.
The data processor inside the module carries out the phase computing unit operation,
the reading of waveform data from the waveform memory, and the configuration of the
waveform output D/A.

1-2 IM 707281-01E
1.2 System Configuration and Block Diagram
System Configuration
The following shows an example in which a 4-CH D/A Module WE7281 is installed in the
measuring station and the measuring station is connected to the PC through the optical
fiber cable.
Optical fiber cable
WE7281
PC
Optical interface card
Measuring station
Optical interface
module
Waveform output
Device receiving
waveform output
Download arbitrary
waveform data
Block Diagram
WE Bus
WE Bus
interface
Module control
Program
Flash memory
Waveform
memory
Data
processor
Data processing
program
memory
Isolation
D/A
Programmable
LPF
ATT
Output amp
CH1
CH2
CH3
CH4
The data processor on the module creates and processes the waveform data according
to instructions from the PC that are received via the WE bus of the measuring station.
The waveform data passes through the isolator. Then, they are converted to analog
values using the D/A converters of each channel. The programmable LPF, that is
optimized according to the waveform, removes the high frequency components. Then,
the ATT adjusts the level of the signal according to the output range, and then finally the
output amplifier outputs the analog signal. The isolators of each channel are independent,
and each channel is isolated from one another.

1-3
IM 707281-01E
1
Explanation of Functions
1.3 Waveforms That Can Be Generated
This module has the following three waveform generation modes. One mode is selected
and the waveform is generated.
DC : DC signal
AG : Arbitrary waveform
FG : Sine wave, pulse wave, ramp wave, triangular wave, arbitrary wave, and DC
signal.
The functional differences between each waveform generation mode are as follows:
DC AG FG
Generated waveform Constant voltage output Loaded arbitrary waveform Sine, pulse, ramp,
triangular, loaded
arbitrary waveform, etc.
Arbitrary waveform No Yes Yes
downloading
Output frequency —— 1 mHz to 10 kHz*
Operation mode Cont One Shot Cont
Trigger Cont Trigger
Gate Trigger Gate
Repeat
Sweep No No Frequency, amplitude,
duty
Offset voltage No No Yes
Phase No No Yes
*1 mHz to 20 kHz during sine wave generation.
The differences between the creation and generation of arbitrary waveforms in the AG
mode and in the FG mode are as follows:
AG mode
•Used when outputting pattern waveforms.
•The maximum allowable data length is 4 Mwords/CH (when using 1 CH)
•Data saved by digital oscilloscope and digitizer modules can be used directly.
•Each channel of waveform memory can be divided into multiple blocks and waveform
data can be loaded to the individual blocks.
FG mode
•Used when outputting a constant waveform in units of one cycle.
•The data length is fixed to 64 Kwords.
•The output frequency can be set up to 10 kHz (20 kHz for sine waves).
•The frequency and amplitude can be specified.
•Frequency and amplitude sweeps are possible.
•The offset and phase difference between channels can be specified.

1-4 IM 707281-01E
1.4 Waveform Generation in the DC Mode
Setting the Output Conditions
You can turn ON/OFF the output and set the output voltage range for each channel.
Setting the output voltage range
You can select the range from the following list of choices.
Setting Possible Output Range Resolution
1 V –1 to 1 V 0.1 mV
2 V –2 to 2 V 1 mV
5 V –5 to 5 V 1 mV
10 V –10 to 10 V 1 mV
Setting the output voltage
You can set an output voltage that falls within the allowed range that corresponds to the
specified output voltage range setting.
Trigger signal output
A trigger signal is output to the WE bus of the measuring station when the output value of
the specified channel is changed.
Selecting the Output Mode
The following three modes are available.
Continuous output
Continuously outputs the DC voltage signal at the specified level.
Output ON
OFF
0 V
Output voltage
Trigger output
Outputs the DC voltage signal at the specified level when a trigger occurs.
Output ON
OFF
Output voltage
Trigger signal
0 V
Gate output
Outputs the DC voltage signal at the specified level while the gate signal is enabled.
Output ON
OFF
Output voltage 0 V
Gate signal
Note
•When the output mode is set to [Trigger], the trigger can be activated by inputting the bus
trigger signal* or by clicking the [Manual Trigger] button on the operation panel.
•When the output mode is set to [Gate], the gate can be opened or closed by inputting the bus
trigger signal* as a gate signal or by pressing down on the [Manual Trigger] button on the
operation panel for the desired amount of time during which the signal is enabled.
* A trigger signal that is provided via the WE bus of the measuring station. For details, see the
WE7000 User’s Manual (IM 707001-01E).