Keithley DAS-1800 Series
Using DriverLINX with Your
Hardware
Information in this document is subject to change without notice. The software
described is this document is furnished under a license agreement. The software may
be used or copied only in accordance with the terms of the agreement.
SCIENTIFIC SOFTWARE TOOLS, INC. SHALL NOT BE LIABLE FOR ANY
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RELATED TO
THE USE OF THIS PRODUCT. THIS PRODUCT IS NOT DESIGNED WITH
COMPONENTS OF A LEVEL OF RELIABILITY SUITABLE FOR USE IN LIFE
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Keithley DAS-1800 Series: Using DriverLINX with Your Hardware
Copyright 1999 by Scientific Software Tools, Inc.
All rights reserved.
First Printing.
SST 20-0599-2
DriverLINX, SSTNET, and LabOBJX are registered trademarks and
DriverLINX/VB is a trademark of Scientific Software Tools, Inc.
MetraByte is a trademark of Keithley Instruments, Inc.
Microsoft and Windows are registered trademarks and Visual C++ and Visual Basic
are trademarks of Microsoft Corporation.
Borland is a registered trademark and Borland C++ and Delphi are trademarks of
Borland International, Inc.
All other brand and product names are trademarks or registered trademarks of their
respective companies.
Contents
Preface 5
Software License and Software Disclaimer of Warranty............................................................5
About DriverLINX.....................................................................................................................7
About This User’s Guide...........................................................................................................7
Conventions Used in This Manual.............................................................................................9
Configuring the DAS-1800 Series 11
Introduction..............................................................................................................................11
Configure DriverLINX Device Dialog.....................................................................................11
Using the DAS-1800 Series with DriverLINX 27
Introduction..............................................................................................................................27
DriverLINX Hardware Model for DAS-1800 Series...............................................................27
Connecting Signals to the DAS-1800 Series............................................................................33
Device Subsystem....................................................................................................................37
Analog Input Subsystem ..........................................................................................................38
Device Subsystem Page.............................................................................................13
Analog Input Subsystem Page ...................................................................................19
Analog Output Subsystem Page.................................................................................20
Digital Input Subsystem Page....................................................................................22
Digital Output Subsystem Page .................................................................................24
Counter/Timer Subsystem Page.................................................................................26
DriverLINX Subsystems............................................................................................27
DriverLINX Modes ...................................................................................................28
DriverLINX Operations and Events..........................................................................30
Logical Channels.......................................................................................................32
Buffers.......................................................................................................................32
Analog Input Subsystem Signals................................................................................33
Analog Output Subsystem Signals .............................................................................35
Digital Input Subsystem Signals................................................................................36
Digital Output Subsystem Signals..............................................................................36
Counter/Timer Subsystem Signals.............................................................................36
Device Modes............................................................................................................37
Device Operations .....................................................................................................37
Analog Input Modes..................................................................................................38
Analog Input Operations............................................................................................38
Analog Input Pacing, Triggering and Gating Options................................................38
Analog Input Timing Events......................................................................................40
Analog Input Start Events..........................................................................................49
Analog Input Stop Events..........................................................................................51
Analog Input Channels...............................................................................................53
Analog Input Expansion Channels.............................................................................58
Keithley DAS-1800 Series Contents • 3
Analog Input Buffers .................................................................................................60
Analog Input Data Coding.........................................................................................61
Analog Input Messages..............................................................................................63
Analog Output Subsystem........................................................................................................64
Analog Output Modes................................................................................................64
Analog Output Operations.........................................................................................64
Analog Output Pacing, Triggering and Gating Options.............................................64
Analog Output Timing Events...................................................................................66
Analog Output Start Events .......................................................................................72
Analog Output Stop Events........................................................................................76
Analog Output Channels............................................................................................77
Analog Output Channel Gains...................................................................................79
Analog Output Buffers...............................................................................................80
Analog Output Data Coding ......................................................................................81
Analog Output Messages...........................................................................................83
Digital Input Subsystem...........................................................................................................84
Digital Input Modes...................................................................................................84
Digital Input Operations............................................................................................84
Digital Input Pacing, Triggering and Gating Options................................................84
Digital Input Timing Events ......................................................................................85
Digital Input Start Events...........................................................................................87
Digital Input Stop Events...........................................................................................87
Digital Input Channels...............................................................................................88
Digital Input Buffers..................................................................................................90
Digital Input Messages..............................................................................................91
Digital Output Subsystem ........................................................................................................93
Digital Output Modes................................................................................................93
Digital Output Operations..........................................................................................93
Digital Output Pacing, Triggering and Gating Options..............................................93
Digital Output Timing Events....................................................................................94
Digital Output Start Events........................................................................................97
Digital Output Stop Events........................................................................................97
Digital Output Channels............................................................................................. 97
Digital Output Buffers.............................................................................................100
Digital Output Messages..........................................................................................101
Counter/Timer Subsystem......................................................................................................102
Uninstalling DriverLINX 105
How do I uninstall DriverLINX? ...........................................................................................105
Troubleshooting 107
Solving Problems...................................................................................................................107
Solving Problems Installing Drivers........................................................................107
Solving Problems Configuring the Drivers..............................................................107
Solving Problems Loading Drivers..........................................................................108
Generating a DriverLINX Configuration Report ................................................................... 111
What is in the Report? .............................................................................................111
How do I Generate the Report?...............................................................................111
Glossary of Terms 112
4 • Contents Keithley DAS-1800 Series
Preface
Software License and Software Disclaimer of Warranty
This is a legal document which is an agreement between you, the Licensee, and S cientific Software Tools, Inc. By opening this
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Software Disclaimer of Warranty.
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Licensing Agreement
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Keithley DAS-1800 Series Preface • 5
Limited Warranty
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Except as specifical ly set forth herein, the sof tware and accom panying writ ten material s (incl uding inst ructions for use) are prov ided
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Tools, Inc. or its distributors, agents or employees.
EXCEPT AS SET FORTH HEREIN, THE RE ARE NO OTHER WARRANT IE S, EI THER EXPRESS OR IMPLIED, INCLUDING BUT
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either (a) return of the price paid or (b) repair or replacement of the software or accompanying materials . In the event of a defect in
material or workmanship, t he item may be returned within the warranty period to S cientific Software Tools f or a replacement without
charge, provided the licensee prev iously sent in the limited warranty registration board to Sc ientific S oftware Tools, Inc ., or can furnish
proof of the purchase of the program. This remedy is void if failure has resulted from accident, abuse, or misapplication. Any
replacement will be warranted for the remainder of the original warranty period.
NEITHER SCIENTIFIC SOFTWARE TOOLS, INC. NOR ANYONE ELSE WHO HAS BEEN INVOLVED IN THE CREATION,
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LICENSEE.
This agreement is governed by the laws of the Commonwealth of Pennsylvania.
6 • Preface Keithley DAS-1800 Series
About DriverLINX
Welcome to DriverLINX for Microsoft Windows, the high-performance realtime data-acquisition device drivers for Windows application development.
DriverLINX is a language- and hardware-indepe ndent applic ation programming
interface designed to support hardware manufacturers’ high-speed analog, digital,
and counter/timer data-acquisition boards in Windows. DriverLINX is a multi-user
and multitasking data-acquisition resource manager providing more than 100 services
for foreground and background data acquisition tasks.
Included with your DriverLINX package are the following items:
•
The DriverLINX API DLLs and drivers supporting your dataacquisition hardware
•
Analog I/O Panel, a DriverLINX program that verifies the installation
and configuration of DriverLINX for your analog input/output board
and demonstrate s several virtual bench-top instruments
•
Source code for the sample programs
•
The DriverLINX Application Programming Interface files for your
compiler
•
DriverLINX On-line Help System
•
DriverLINX 4.0 Installation and Configuration Guide
•
DriverLINX Analog I/O Programming Guide
•
DriverLINX Technical Reference Manual
•
Supplemental Documentation on DriverLINX and your data-acquisition
hardware
About This User’s Guide
The purpose of this manual is to help you quickly learn how to configure and use t he
hardware features of Keithley’s DAS-1800 Series boards with DriverLINX.
•
For help instal l ing and configuring your ha rdware and DriverLINX,
please see the manual that accompanied your hardware and the
DriverLINX 4.0 Installation and Configuration Guide for your version
of Windows.
•
For more information on the DriverLINX API, please see the
DriverLINX Technical Reference Manual.
•
For additional help programming your board, please examine the source
code examples on the Distribution Disks.
This manual contains the following chapters:
Configuring the DAS-1800 Series
Shows how to configure the DAS-1800 Series using the Configure DriverLINX
Device dialog box.
Using the DAS-1800 Series with DriverLINX
Keithley DAS-1800 Series Preface • 7
Shows how to set up DriverLINX with the Edit Service Request dialog box to use
DAS-1800 Series hardware features.
Uninstalling DriverLINX
Describes how to remove DriverLINX hardware drivers and other files.
Troubleshooting
Gives troubleshooting tips for installing, configur ing, and loading D riverLINX
drivers.
8 • Preface Keithley DAS-1800 Series
Conventions Used in This Manual
The following notational conventions are used in this manual:
•
A round bullet (•) identifies itemized lists.
•
Numbered lists indicate a step-by-step procedure.
•
DriverLINX Application Programming Interface and Windows macro
and function names are set in bold when mentioned in the text.
• DriverLINX indicates the exported function name of the device driver
DLL while DriverLINX indicates the product as a whole.
•
DriverLINX Application Programming Interface identifiers, menu
items, and Dialog Box names are italicized when mentioned in the text.
•
Italics are used for emphasis.
•
Source code and data structure examples are displayed in Courier
typeface and bounded by a box with a single line.
Code
•
A box with a double line bound tables of information.
Tables
Concept
•
Important concepts and notes are printed in the left margin.
Keithley DAS-1800 Series Preface • 9
Configuring the DAS-1800 Series
Introduction
The installation program provides general instructions for installing and configuring
DriverLINX. This manual explains the steps and special features that apply to
Keithley’s DAS-1800 Series boards.
Installing and configuring DriverLINX for a Keithley DAS-1800 Series board
requires three steps:
1. Install DriverLINX. Follow the instructions given by the installation
program. The Read Me First instructions explain the components and
drivers you can install.
2. Configure DriverLINX. This creates a Logical Device, which stores
configuration information for your board. See “Configure Dri verLINX
Device Dialog” on page 11 for configuration options specific to a
Keithley DAS-1800 Series model.
3. Install your DAS-1800 hardware. Follow the instructions in your
hardware manual.
After configuring DriverLINX, instal l ing your board and restarting Windows, reopen
the DriverLINX Configuration Panel to make sure that DriverLINX loaded the
Logical Device for your board. If the Logical Device is not loaded, the Event Log
may have a message from the driver that explains why. You can check the Event Log
using the DriverLINX Event Viewer on the Windows Start Menu.
Configure DriverLINX Device Dialog
DriverLINX uses a standardized configuration protocol for all data-acquisition
hardware. Configuration assigns a port address, interrupt resources a nd a
DriverLINX Logical Device number to a specific DAS-1800 Series board in your
computer.
The installation program automatically starts the DriverLINX Configuration Panel.
To start it now, use the shortcut on the Windows Start Menu.
Keithley DAS-1800 Series Configuring the DAS-1800 Series • 11
When you click the Configure… button on the DriverLINX Configuration Panel,
DriverLINX displays the Configure DriverLINX Device dialog. The dialog has a
page for each subsystem on a Keithley DAS-1800 Series model. The following
sections describe your choices in configuring DriverLINX to work with your board.
12 • Configuring the DAS-1800 Series Keithley DAS-1800 Series
Device Subsystem Page
Use the Device subsystem page to tell DriverLINX the model name, address and,
optionally, the expansion accessories connected to your DAS-1800 Series board.
Vendor
The Vendor property displays “Keithley MetraByte” It is a read-only property.
Device
Windows NT
The Device property designates the Logical Device you are configuring. It is a readonly property. To change it, first save (OK) or quit (Cancel) the current
configuration. Then select or create a new Logical Device using the DriverLINX
Configuration Panel.
Model
The Model property selects or indicates the hardware model of the board you’re
configuring.
Select one of the following models:
DAS-1801ST
DAS-1802ST
DAS-1802HR
DAS-1801HC
DAS-1802HC
DAS-1801AO
DAS-1802AO
DAS-1801ST-DA
DAS-1802ST-DA
DAS-1802HR-DA
Keithley DAS-1800 Series Configuring the DAS-1800 Series • 13
Windows 95/98
Under Windows 95/98, DriverLINX displays the model you chose during
installation. To install a different model, cancel the configuration and run Add New
Hardware from the Windows Control Panel.
Address
The Address property records the I/O port address for the board. The default address
used by DriverLINX is 0x300 hexadecimal or 768 decimal.
The DAS-1800 has a 6-bit DIP switch that sets its base address. Each switch
corresponds to a binary digit in the address. When a switch is up, or in the ON
position, its digit is 0. When it’s down, its digit is 1.
The switches select the value of the 1
address are 0. That is, there are four zeros to the right of the bits represented by the
switches.
For example, the following DIP switch shows the setting for 11 0000 0000
(0x300 hexadecimal or 768 decimal).
st
to the 6th digits. The 7th to the 10th digits of the
Windows NT
Windows 95/98
Enter your board’s base I/O address. Note: you need a block of sixteen free
addresses. AO models use an additional block of ten addresses starting at
base + 0x400.
Under Windows 95/98, Add New Hardware automatically selects an appropriate
address. To change the setting, see “Using the Windo ws 95/98 Device Ma nager” on
page 17.
Detect
The Detect property enables and disables DriverLINX’s hardware detection and
testing algorithms. For maximum system reliability, always leave this check-box
marked.
Calibrate
The Calibrate property enables and disables hardware auto-calibration. This option is
grayed-out for the DAS-1800 Series because it does not support automatic
calibration.
14 • Configuring the DAS-1800 Series Keithley DAS-1800 Series
Special…
The Special… button displays the following dialog box of DAS-1800 Series-specific
configuration options:
Common-mode reference
The DAS-1800 has two grounding options for single-ended analog inputs. They
determine the ground reference for the ADC input amplifier.
•
LL GND — references the analog ground connection.
•
U_CM MD — re ferences the user-c ommon mode ground connection.
Use the U_CM MD setting to eliminate ground loops. See your DAS-1800 User’s
Guide for more details.
Number of EXP-1800s
You can expand the number of single-ended analog input channels connected to your
DAS-1800 board by using one to sixteen EXP-1800 expansion boards. Each EXP1800 is 1-to-16 multiplexer that replaces one onboard channel with sixteen expansion
channels. Configure your DriverLINX Logical Device to use the additional channels
by entering the number of EXP-1800s here. See “Analog Input Expansion Channels”
on page 58 for details on accessing multiplexer channels.
Simultaneous sample and hold configuration
You can provide for simultaneous analog input sampling using external Simultaneous
Sample and Hold (SSH-8) units. A DAS-1800HC model can have up to eight SSH-8
units. Other models can have up to two SSH-8 units. In the Configure DAS-1800
Options dialog box, enter the number of SSH-8s connected.
Keithley DAS-1800 Series Configuring the DAS-1800 Series • 15
For each SSH-8 unit, select its number in the SSH # list box and enter the following
configuration parameters:
•
Base channel — Each SSH-8 replaces 8 DAS-1800 channels
determined by which accessory and SSH-8 connectors you use and the
offset jumper settings on the SSH-8. You can connect two SSH-8 units
to one accessory connector by daisy chaining them together using the
connectors inside the units. See the SSH-8 User’s Guide for details.
Select the base channel corresponding to the connectors you are using
for this SSH-8 unit:
Accessory Base Channel
Connector Directly
connected
SSH-8
STA-1800U
J3 0 0
STA-1800HC
J1 0 24
J2 8 32
J3 16 40
J4 24 48
Daisy-chain
connected
SSH-8
•
Channel offset — click on an SSH-8 channel in the list and then select
the channel offset that corresponds to the position of the Output
Channel Jumper on the SSH-8. The list displays the number of the
DAS-1800 channel that the SSH-8 channel replaces.
Usually, you would configure all channels on a directly connected SSH8 to the lower offset channels (0-7) and all channels on a daisy-chain
connected SSH-8 to the higher offset channels (8-15).
•
Channel gain — click on an SSH-8 channel in the list and then select its
SSH-8 external amplifier gain. SSH-8FG models have a fixed gain of
0.5. SSH-8SG models have switches to set the gain of each channel.
For information on programming a task for simultaneous sampling, see “Rate
Generator: Internal Clocki ng” on page 41 o r “Rate Generator: External Clocking” on
page 43.
Disable AO recycle mode
For the DAS-1800AO hardware, DriverLINX can automatically promote AO tasks
meeting certain criteria to run from the DAC FIFO buffer in recycle mode. If the
Disable AO recycle mode box is checked, DriverLINX will not use recycle mode. If
the box is not checked, DriverLINX will use recycle mode for applicable tasks.
In recycle mode, DriverLINX automatically promotes AO tasks meeting the
following criteria as specified in the Service Request to run from the DAC FIFO
buffer in re -cycle mode:
16 • Configuring the DAS-1800 Series Keithley DAS-1800 Series
Service Request Property Value
Request mode Interrupt
Stop event type Command
Buffer notify flag False
Buffer samples × Number of buffers
The advantages of using the DAC FIFO buffer for free-run, re-cycle mode analog
output are:
•
The DAS-1800AO’s digital trigger operates in retrigger mode, enabling
you to synchronize analog output with a recurring external signal.
•
Traffic on the memory bus is significantly reduced at high output rates.
•
The system response latency will be noticeably shortened.
•
The analog output timing will be immune to traffic on the memory and
I/O buses.
The disadvantages are:
•
You can’t change the analog output values while the analog output task
is running.
•
There is a delay while DriverLINX loads the FIFO.
< 2048
•
Buffer-filled notification messages cannot be posted, as the hardware
does not permit detection of end-of-buffer conditions.
•
The STATUS operation cannot provide the “number of buffers
processed” report.
Using the Windows 95/98 Device Manager
Under Windows 95/98, DriverLINX uses the address and interrupt settings
maintained by the Windows Device Manager.
To view or change the settings for your board using the Devi ce Manager:
1. Start the Device Manger by right-clic king on My Computer and
selecting Properties or click here
2. Click the Device Manger tab.
3. Click the
list.
4. Under DriverLINX drivers, select the entry for your board. (It may or
may not have
next to , if necessary to expand the
next to it.)
.
Keithley DAS-1800 Series Configuring the DAS-1800 Series • 17
5. Click the Properties button.
6. On the board’s property page, click the Resources tab.
7. To change the number and type of resources, select a different Basic
Configuration und er Setting based on.
8. To change a resource setting, select it under Resource Type and click
the Change Setting button. Windows will guide you in selecting an
appropriate value.
9. When you are done, click OK to close the board’s property page.
10. The board’s a ddress switches must match the address setting you select.
If necessary shut down your computer and reposition them as described
in your hardware manual.
11. Restart Windows to load the Logical Device for your board using the
new settings.
18 • Configuring the DAS-1800 Series Keithley DAS-1800 Series
Analog Input Subsystem Page
Use the Analog Input subsystem page to choose between single-ended or differential
analog input connections and to set or view your board’s interrupt request level.
Channels
On the DAS-1800HC, Analog Input channel configuration is software programmable
for 64 single-ended or 32 differential analog inputs. On all other DAS-1800 boards,
Analog Input channel configuration is software programmable for 16 single-ended or
8 differential analog inputs.
Windows NT
Windows 95/98
When configuring the Analog Input Subsystem, you choose a default configuration
for all channels. Applications can use the default configuration or specify the
connection type for each channel it uses. This scheme supports applications that use
KPCI-1800-specific features as well as those that use only generic features. For
programming information, see “Analog Input Channels” on page 53.
Range
The analog input ranges for the DAS-1800 Series are fully software programmable.
DriverLINX grays out this property in the configuration dialog.
Interrupt
Configure the board with an interrupt for full support of the board’s capabilities.
For Windows NT, select a free interrupt request level to support interrupt or DMA
mode transfers. Valid IRQ settings are: 3, 5, 7, 10, 11, 15 and None.
Under Windows 95/98, Add New Hard ware automatically selects an appropriate
interrupt. To change the sett ing, see “Using the Wind ows 95/98 Device Manager” on
page 17.
DMA
Configure the board with a DMA channel for full support of the board’s capabilities.
For Windows NT, select a free DMA channel to support DMA mode transfers. Valid
DMA settings are: 5, 6, 7 and None.
Keithley DAS-1800 Series Configuring the DAS-1800 Series • 19
Under Windows 95/98, Add New Hard ware automatically selects an appropriate
DMA channel. To change the setting, se e “Using the Windows 95/98 Device
Manager” on page 17.
Analog Output Subsystem Page
Note: The Configure DriverLINX Device dialog shows the Analog Output
Subsystem Page only for applicable models.
Use the Analog Output subsystem page to set or view the subsystem’s DMA channel
and initial output voltages.
Windows NT
Channels
Lists the analog output channels on the board and selects a channel for the Volts and
Initialize properties.
Range
The analog output ranges for the DAS-1800 Series are fully software programmable.
DriverLINX grays out this property in the configuration dialog.
Volts
The Initialization Value property specifies the analog output value DriverLINX will
write to the selected Logical Channel upon hardware initialization. DriverLINX only
writes this value if you enable the Initialize check box.
Interrupt
The DAS-1800 Series uses the same interrupt for analog output as for analog input.
Go to the Analog Input subsystem page to view or set it.
DMA
DMA applies only to the DAS-1801AO and DAS-1802AO models. Configure the
board with a DMA channel for full support of the board’s capabilities.
For Windows NT, select a free DMA channel to support DMA mode transfers. Valid
DMA settings are: 5, 6, 7 and None.
20 • Configuring the DAS-1800 Series Keithley DAS-1800 Series
Windows 95/98
Under Windows 95/98, Add New Hard ware automatically selects an appropriate
DMA channel. To change the setting, se e “Using the Windows 95/98 Device
Manager” on page 17.
Initialize
Checking the Initialize check box instructs DriverLINX to use the Volts property to
initialize the selected analog output channel.
Keithley DAS-1800 Series Configuring the DAS-1800 Series • 21
For the DAS-1800 Series,
there are no configurable
options on the Digital Input
subsystem page.
Digital Input Subsystem Page
Channels
The Channels prop erty allows you to select a Logical Channel for configuration or
viewing the channel’s range. The DAS-1800 Series digital channels have fixed
configurations.
DriverLINX defines the following Logical Channels for the DAS-1800 Series digital
inputs:
Logical
Channel
0 Standard Digital Input DI 0 … DI 3
1 External Clock XPCLK
2 External Trigge r TGIN
DriverLINX Function DAS-1800 Series
External Connector
Range
The Range property specifies the supported digital input range for the selected
Logical Channel. This is a read-only property.
Interrupt
The DAS-1800 Series does not use interrupts for the digital input subsystem.
DriverLINX disables this property and displays it as blank.
DMA
The DAS-1800 Series does not use system DMA channels. DriverLINX disables this
property and displays it as blank.
22 • Configuring the DAS-1800 Series Keithley DAS-1800 Series
Configuration Setup
The Configuration Setup property specifies the hardware configuration of the digital
I/O ports. The DAS-1800 Series has a fixed digital I/O configuration. Therefore,
DriverLINX disables this field.
Initialize
Checking the Initialize check box instructs DriverLINX to use the Configuration
Setup property to configure the digital I/O ports. The DAS-1800 Series has a fixed
digital I/O configuration. Therefore, DriverLINX disables this field.
Keithley DAS-1800 Series Configuring the DAS-1800 Series • 23
Digital Output Subsystem Page
Use the Digital Output subsystem page to change the default digital output port
initialization values.
Channels
The Channels property allows you to select a Logical Channel for initialization or
viewing the channel’s range . DriverLINX defines the follo wing Logical Channels for
the DAS-1800 Series digital outputs:
Logical Channel DriverLINX
Function
0 (HC models) Standard Digital Output DO 0 … DO 7
0 (except HC models) Standard Digital Output DO 0 … DO 3
1 (except HC models) Standard Digital Output MUX4 … MUX7, GEXT
The Analog Input subsystem uses the MUX outputs to control an EXP-1800
expansion accessory. If you are not using an EXP-1800, you can use the MUX
outputs as anot her Digital Output channel. However, you can change its value onl y
while the Analog Input subsystem is inactive.
DAS-1800 Series
External Connector
Range
The Range property specifies the supported digital output range for the selected
Logical Channel. This is a read-only property.
Interrupt
The DAS-1800 Series does not use interrupts for the digital output subsystem.
DriverLINX disables this property and displays it as blank.
DMA
The DAS-1800 Series does not use system DMA channels for Digital Output.
DriverLINX disables this property and displays it as blank.
24 • Configuring the DAS-1800 Series Keithley DAS-1800 Series
Initialization Value
The Initialization Value property specifies the digital output value DriverLINX will
write to the selected Logical Channel upon hardware initialization. DriverLINX only
writes this value if you enable the Initialize check box.
By default, DriverLINX uses the hardware-defined initialization values if the
Initialize check box is not checked. For the DAS-1800 Series, the default digital
output value is zero.
Initialize
Checking the Initialize check box instructs DriverLINX to use the Initialization
Value property for digital output port initialization.
Dec
This check box converts the Initialization Value property to decimal.
Hex
This check box converts the Initialization Value property to hexadecimal.
Keithley DAS-1800 Series Configuring the DAS-1800 Series • 25
For the DAS-1800 Series,
there are no configurable
options on the Counter/Timer
subsystem page.
Counter/Timer Subsystem Page
Resolution
The Resolution property specifies the clock frequency of the master oscillator. All
models have a 5.0 MHz clock source for pacing analog input. AO models also use
the 5.0 MHz clock source for pacing analog output.
Interrupt
The DAS-1800 Series does not support interrupts from counter/timers. DriverLINX
disables this property and displays it as blank.
26 • Configuring the DAS-1800 Series Keithley DAS-1800 Series
Using the DAS-1800 Series with DriverLINX
Introduction
See the Analog I /O
Programming Guide for an
overview of DriverLINX
programming.
This chapter shows you how to set up and use DAS-1800 Series hardware features
with DriverLINX.
The descriptions here use the Edit Service Request dialog for language and API
independence. For the corr ect syntax with the language you’re using, p lease see the
DriverLINX Technical Reference Manuals. For DriverLINX examples in your
programming language, p lease see the sourc e code examples in the subdirectories of
your DriverLINX installation directory or on the original distribution media.
DriverLINX Hardware Model for DAS-1800 Series
DriverLINX provides a portable, hardware-independent API for data-acquisition
boards while still allowing applications to access unique or proprietary hardware
features of specific products. To achieve this goal, DriverLINX maps a hardwareindependent, or abstract, data-acquisition model onto DAS-1800 Series hardware
capabilities.
The following sections describe how DriverLINX implements DAS-1800 Series
hardware features as Subsystems, Modes, Operations, Events, Logical Channels,
Buffers, and Messages.
DriverLINX Subsystems
The DAS-1800 Series supports the following DriverLINX subsystems:
1. Device—refers to a DAS-1800 board as a whole.
2. Analog Input—refers to the analog input channels, clocks, and control
signals.
3. Analog Output—refers to the analog output channels, clocks, and
control signals. DA, HC and AO models only.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 27
4. Digital Input—refers to the digital input port as well as 1-bit digital
input (TTL) control signals, such as TGIN.
5. Digital Output—refers to the digital output port and control signals.
6. Counter/Timer—refers to the input/output subsystem-specific internal
clock channels for pacing analog input/output.
DriverLINX Modes
Applications use modes in Service Requests to advise DriverLINX on their preferred
hardware data transfer technique. The DriverLINX modes fall into two general
classes:
•
Foreground or synchronous modes. The calling application doesn’t
regain control until DriverLINX completes the Service Request.
DriverLINX supports this mode for simple, single value I/O operations
or software housekeeping functions that DriverLINX can complete
without a significant delay.
•
Background or asynchronous modes. The calling application regains
control as soon as DriverLINX initiates the task. The calling application
must synchronize with the data-acquisition task using status polling or
DriverLINX’s messages (preferred). DriverLINX supports this mode
for buffered data transfers or for commands that require a significant
time to complete.
DriverLINX supports four modes with the DAS-1800 Series for its commands
(Service Requests).
•
Polled Mode—T his is a foreground or synchronous operation.
DriverLINX supports this mode for simple, single-value I/O operations
that the data-acquisition board can complete without significant delay.
•
Interrupt Mode—Thi s is a background or asynchronous operation.
DriverLINX transfers data between the computer’s memory and the
data-acquisition board using hardware interrupts and programmed I/O
transfers.
•
DMA Mode—This is a background or asynchronous operation.
DriverLINX programs the data-acquisition board to transfer data
between the computer’s memory and the board.
•
Other Mode—This is a foreground or synchronous opera tion.
DriverLINX supports this mode for initialization, configuration,
calibration, data conversion, and timebase operations.
28 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
The following table summarizes the data acquisition modes that DriverLINX
supports for each subsystem with the Keithley DAS-1800 Series.
Subsystem Polled Interrupt DMA Other
Analog Input
Analog Ou tput
(DA and HC
models)
Analog Ou tput
(AO models)
Digital Input
Digital Output
Counter/Timer
Device
√√√√
√√ √
√√√√
√√ √
√√ √
√
√
DAS-1800 Series Supported DriverLINX Modes.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 29
DriverLINX Operations and Events
Applications construct DriverLINX data-acquisition tasks by combining a small
number of DriverLINX operations and events in many possible ways. The following
table summarizes the operations and events that DriverLINX supports for the
Keithley DAS-1800 Series. Later sections for each DriverLINX subsystem will
describe the operations and events in more detail.
Note: In addition to the operations shown in the table below, all subsystems allow
the MESSAGE operation in any Mode.
30 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Subsystem Operation Events
Mode Timing Start Stop
Analog Input
Polled Start, Co nvert null null, cmd null, TC
Interrupt Start, Stop,
Status,
Convert
DMA Start, Stop,
Status,
Convert
Other Initialize
Analog Output (DA, HC and AO models only)
Polled Start, Convert null null, cmd null, TC
Interrupt (AO
models only)
Start, Stop,
Status,
Convert
DMA (AO
models only)
Start, Stop,
Status,
Convert
Other Initialize
dig, rate cmd, dig cmd, TC, dig
dig, rate cmd, dig cmd, TC, dig
dig, rate cmd, dig cmd, TC
dig, rate cmd, dig cmd, TC
Digital Input
Polled Start null null, cmd null, TC
Interrupt Start, Stop,
rate cmd cmd, TC
Status
Other Initialize
Digital Output
Polled Start null null, cmd null, TC
Interrupt Start, Stop,
rate cmd cmd, TC
Interrupt
Other Initialize
Counter/Timer
Other Initialize
Device
Other Initialize,
Capabilities
Allowed Operations and Events for DAS-1800 Series Subsystems and Modes.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 31
The following list explains the Event abbreviations in the preceding table:
•
null—Null or None Event when a Service Request doesn’t require an
event
•
cmd—Command Event when DriverLINX starts or stops a task on
software command
•
TC—Terminal Count Event when DriverLINX processes all data
buffers once
•
rate—Rate Event specifies how DriverLINX paces or clocks data
transfer
•
dig—Digital Event specifies a trigger, clock, or other control signal to
pace, start, or stop a task
Logical Channels
DriverLINX designates the individually addressable hardware channels for each
subsystem as “Logical Channels.” Generally, the zero-based Logical Channel
numbering sequence closely follows the hardware manufacturer’s cha nnel numbering
scheme.
In some cases, however, DriverLINX assigns Logical Channel numbers to hardware
features that users don’t commonly think of as “channels.” For instance, DriverLINX
commonly models external hardware clock input lines, external hardware trigger
input lines, and external interrupt inputs as 1-bit digital Logical Channels. In other
cases, DriverLINX models subsystem-specific features, such as internal pacer clocks,
as members of a more general-purpose set of counter/timer channels.
For a list of DriverLINX assigned Logical Channel numbers, see the notes on each
supported subsystem.
Buffers
Applications usually use data buffers to exchange data between the application and
the data-acquisition hardware. When using data buffers, please note the following
points about DriverLINX’s data buffers:
•
DriverLINX supports data-acquisition tasks with 1 to 255 data buffers
per task.
•
DriverLINX i mposes no size limits o n a single buffer, alt hough the
operating system or some hardware products may have size restrictions.
•
User applications must allow DriverLINX to allocate all data buffers to
guarantee application portability to different hardware and operating
systems and to insure that the hardware can physically access the buffer
memory.
•
User applications usually don’t have concurrent or immediate access to
the in-use data buffer while DriverLINX is executing a data-acquisition
task.
32 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Connecting Signals to the DAS-1800 Series
The Keithley hardware manual describes the data and control signals for the DAS1800 Series and the connector pinouts for these signals. This section summarizes how
DriverLINX numbers the I/O data signals and how DriverLINX uses the control
connections for external clock, trigger, a nd gating inputs.
Analog Input Subsystem Signals
The Analog Input subsystem has 8 differential, 32 differential, 16 single-ended or
64 single-ended analog input connections, depending on the model and configuration
of your DAS-1800 board.
DriverLINX maps these connections to Logical Channels as shown in the following
table:
Physical Channels Connector Name Logical
0 – 7 Differential CH00LO, HI – CH07LO, HI 0 – 7
0 – 31 Differential CH00LO, HI – CH31LO, HI 0 – 31
0 – 15 Single-ended CH00LO – CH15LO, LLGND 0 – 15
0 – 15 Single-ended,
User-common mod e
0 – 63 Single-ended CH00LO – CH63LO, AGND 0 – 63
How DriverLINX maps analog input hardware channels to Logical Channels.
CH00LO – CH15LO, U_CM_MD 0 – 15
Channels
Analog Input Pacing, Trigger ing and Gating Signals
Analog input tasks can use the input-pacing counter, which DriverLINX designates
as Counter/Timer Logical Channel 0. For this counter the clock source can be
internal or external.
The Analog Input subsystem uses two control signals that DriverLINX defines as an
external clock and a trigger/gate as shown in the following table:
Connector Name DriverLINX Usage
TGIN External trigger:
•
Digital Start Event (Post-Triggering)
•
Digital Stop Event (Pre- and About-
Triggering)
External gate:
•
Rate Timing Event
•
Digital Start Event (Gating)
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 33
Connector Name DriverLINX Usage
XPCLK External pacer clock:
•
Rate Timing Event
•
Digital Timing Event
How DriverLINX uses analog i nput control signals.
34 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Analog Output Subsystem Signals
The Analog Output subsystem has 2 or 4 analog differential output connections,
depending on the model of your DAS-1800 board.
DriverLINX maps these connections to Logical Channels as shown in the following
table:
Physical Channels Connector Name Logical Channels
0 – 1
(HR-DA and AO models)
0 – 1
(HC models)
0 – 3
(ST-DA models only)
How DriverLINX maps analog output hardware channels to Logical Channels.
Analog Output Pacing, Triggering and Gating Signals
Analog output tasks can use the output-pacing counter, which DriverLINX designates
as Counter/Timer Logical Channel 1. For this counter the clock source can be
internal or external.
The Analog Output subsystem uses two control signals that DriverLINX defines as
an external clock and a trigger as shown in the following table:
ODAC 0 – ODAC 1 0 – 1
DAC0 OUT– DAC1 OUT 0 – 1
ODAC 0 – ODAC 3 0 – 3
Connector Name DriverLINX Usage
TGIN External trigger:
•
Digital Start Event (Post-Triggering)
External gate:
•
Rate Timing Event
•
Digital Start Event (Gating)
XPCLK External pacer clock:
•
Rate Timing Event
•
Digital Timing Event
How DriverLINX uses analog output control signals.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 35
Digital Input Subsystem Signals
The Digital Input subsystem has one 4 or 8-bit digital input port and two control
inputs which DriverLINX models as 1-bit logical digital input ports. DriverLINX
maps these signals to Logical Channels as shown in the following table:
Port Connector Name Logical Channel
4-bit digital input DI 0 … DI 3 0
External clock alias XPCLK 1
External trigger alias TGIN 2
How DriverLINX maps digital input hardware channels to Logical Channel s.
Digital Output Subsystem Signals
The Digital Output subsystem has a 4 or 8-bit digital output port and, except on HC
models, a group of control signals that you can use as an output port. DriverLINX
maps these signals to Logical Channels as shown in the following tables:
HC Models
Port Connector Name Logical Channel
8-bit digital input DO 0 … DO 7 0
How DriverLINX maps digital output hardware channels to Logical Channel s for HC models.
Other Models
Port Connector Name Logical Channel
4-bit digital output DO 0 … DO 3 0
5-bit digital output MUX4 – MUX7, GEXT 1
How DriverLINX maps digital output hardware channels to Logical Channel s of other models.
Counter/Timer Subsystem Signals
The Counter/Timer subsystem has one or two counter/timer channels for analog
input/output pacing. It also has an external clock source and a gate input that the
board can use with any Logical Channel. DriverLINX maps these signals as shown in
the following table:
Timer Connector Name Logical Channel
Input Pacing Counter XPCLK 0
Output Pacing Counter
(AO models only)
How DriverLINX maps counter/ timer hardware channels to Logical Channels .
XPCLK 1
36 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Device Subsystem
The following sections describe how DriverLINX implements Device Subsystem
features for the DAS-1800 Series.
Device Modes
The Device Subsystem supports only DriverLINX’s Other mode for all operations.
Device Operations
The DAS-1800 Series Device Subsystem supports the following DriverLINX
operations:
If another application is using
the same data-acquisition
board, DriverLINX will
prevent Device Initialization
from interfering with another
application’s data-acquisition
tasks.
•
Initialize—DriverLINX aborts all data-acquisition tasks for every
subsystem controlled by the current application. DriverLINX then
initializes each subsystem.
•
Capabilities—DriverLINX provides hardware-specific and
configuration information in the form of a Logical Device Descriptor
database.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 37
Analog Input Subsystem
The following sections describe how DriverLINX implements Analog Input
Subsystem features for the DAS-1800 Series.
Analog Input Modes
The Analog Input Subsystem supports the following modes:
•
Polled—For single-value or single-scan analog input samples.
•
Interrupt—For buffered transfers using programmed I/O.
•
DMA—For buffered transfers using direct memory access.
•
Other—For subsystem initialization and data conversion.
Analog Input Operations
The DAS-1800 Series Analog Input Subsystem supports the following DriverLINX
operations:
•
Initialize—aborts all active analog input data-acquisition tasks.
However, DriverLINX prevents one application from interfering with
another application’s data-acquisition tasks.
•
Start—initiates a data-acquisition task using the Mode, Timing, Start,
and Stop Events, the Logical Channels, and the Buffers the application
specified in the Service Request.
•
Status—reports the buffer position of the next sample that DriverLINX
will write into a buffer.
•
Stop—terminates an analog input data-acquisition task.
•
Message—DriverLINX displays a pop-up dialog box for the user
containing the text for the current DriverLINX error message.
Analog Input Pacing, Triggering and Gating Options
The DAS-1800 Series User’s Guides describe several pacing, triggering and gating
options available on DAS-1800 models. The following table summarizes these
options and identifies which Service Request properties use them. Except as
indicated all tasks must use Interrupt or DMA mode.
38 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Parameter Option Service Request Properties
Pacing Mode
Periodic (paced) Rate generator timing event
Burst Burst generator timing event
Clock Source
Software Single-value or single-scan
(Polled mode)
Internal Rate timing event with an internal
clock source
External +/- Rate timing event with an external
clock source
Digital timing event
Trigger
Internal (software) Command start event
Command stop event
Terminal count stop event
Digital +/- Digital start event
Digital stop event
Trigger Mode
Pre-trigger Digital stop event with 0-delay
About-trigger Digital stop event with positive delay
Post-trigger Digital start event
Trigger-to-trigger Digital start event
Digital stop event
Trigger-to-about-trigger Digital start event
Digital stop event with positive delay
Gate
Level +/- Rate timing event
Digital start event (for use with a
digital timing event)
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 39
Analog Input Timing Events
Timing Events specify how the hardware paces or clocks the acquisition of analog
input samples. DriverLINX uses the Timing Event to program when the DAS-1800
Series acquires the next analog input sample.
The DAS-1800 Series supports the following Timing Events:
•
None—Sampling requires no pacing as DriverLINX is acquiring only a
single value or scan.
•
Rate—The DAS-1800 Series supports fixed rate and burst mode
sampling using internal and external clocks.
•
Digital—DriverLINX uses an external digital input signal to pace the
acquisition of the next sample.
None or Null Timing Event
The Null Event specifies that the task does not need a clock to determine when to
acquire the next sample.
Rate Timing Event
The DAS-1800 Series supports two types of Rate Events for analog input:
•
Rate Generator—Generates a fixed rate clock with equal time
intervals between tics.
•
Burst Generator—Generates a dual frequency clock with a fixed
number of tics at a high frequency separated by a time interval at a
lower frequenc y.
DAS-1800 boards have a 5 MHz master clock frequency, or 0.2 µs tic period. The
sample period can range from 15 tics (3µs) to
sample rate can range from 0.00116 Hz to 333kHz. However, using multiple
channels or non-unity gains may reduce the maximum sample rate that the hardware
can accurately acquire. Consult your hardware manual for details.
32
21
− tics (833 s). This means the
40 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Rate Generator: Internal Clocking
An internally clocked Rate Generator produces a fixed rate clock with equal time
intervals between tics.
Period
Use an internally clocked rate generator when you want to acquire all analog input
samples at equally spaced time intervals.
How to set up the DAS-1800 Seri es for fixed rate sampling using an i nt ernal clock.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 41
For hardware independence,
specify the clock channel
using the symbolic constant,
DEFAULTTIMER, which
always maps to the default
Logical Channel for analog
input timing.
•
Specify internal cl ocking using a Rate Generator on Channel 0 with
the Internal 1 Clock source. See “Counter/Timer Subsystem” on page
102 for a description of clock sources.
•
The Period property specifies the time interval between samples in tics,
where an Internal 1 tic is 0.2 µs, or 5 MHz. The minimum period is 15
tics, or 333 kHz. The maximum period is 4294967295 tics (
0.00116 Hz.
•
The Gate property specifies how the TGIN signal affects the operation
of the internal clock. Valid settings are Enabled, Disabled, and High
Level and Low Level. See “Counter/Timer Subsystem” on page 102 for
a description of each Gate setting.
Note: You cannot use a gated clock with a digital start or stop trigger.
•
For simultaneous sampling using an SSH-8 accessory, check the
Simultaneous box in the Channels section. Simultaneous means that all
selected channels are sampled in each sample period.
Also see: “Repeat Mode Sampling on the DAS-1802HR-DA” on page 57.
32
21
− ), or
42 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Rate Generator: External Clocki ng
An externally clocke d Rate Generator produces a rate clock with unknown time
intervals between tics.
Period (ext clk)
Use an externally clocked rate generator when you want to synchronize analog input
samples with a recurrent external signal. In this mode you will need a separate
external clock tic for each analog sample you want to acquire.
How to set up the DAS-1800 Seri es for fixed rate sampling using an external clock.
Be sure that the external
clock source is TTL
compatible, 0 V minimum to
+5 V maximum!
•
Specify external clocking using a Rate Generator on Channel 0 with
an External, External+, or External- Clock source. See
“Counter/Timer Subsystem” on page 102 for a description of clock
sources. For hardware-independence, you can specify the hardware
external clock channel by the symbolic constant, DI_EXTCLK.
•
Users should connect the external clock signal to the XPCLK line.
•
Specify a Period between the minimum and maximum exte rnal
clocking period. The value doesn’t affect the external clock frequency,
but DriverLINX requires a valid hardware value in case the application
requests a timebase operation and to optimize data transfer between the
driver and the application.
•
The frequency of the external clock must not exceed 333 kHz.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 43
•
The Gate property specifies how the TGIN signal affects the operation
of the internal clock. Valid settings are Enabled, Disabled, and High
Level and Low Level. See “Counter/Timer Subsystem” on page 102 for
a description of each Gate setting.
Note: You cannot use a gated clock with a digital start or stop trigger.
•
For simultaneous sampling using an SSH-8 accessory, check the
Simultaneous box in the Channels section.
Also see: “Repeat Mode Sampling on the DAS-1802HR-DA” on page 57.
44 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Burst Generator: Internal Clocking
An internally clocked Burst Generator produces a dual frequency clock with a fixed
number of tics at a high frequency repeated at a lower frequency.
Use an internally clocked rate generator when you want to acquire analog input
samples from a several channels at closely spaced time intervals and then repeat at
longer intervals.
How to set up the DAS-1800 Seri es for burst mode sampling using an internal c l ock.
For hardware independence,
specify the clock channel
using the symbolic constant,
DEFAULTTIMER, which
always maps to the default
Logical Channel for analog
input timing.
•
Specify internal cl ocking using a Burst Generator on Channel 0 with
the Internal 1 Clock source. See “Counter/Timer Subsystem” on page
102 for a description of clock sources.
•
The Period property specifies the time interval between bursts in tics,
where an Internal 1 tic is 0.2 µs, or 5 MHz. The minimum period is 15
tics, or 333 kHz. The maximum period is 4294967295 tics (
32
21
− ), or
0.000116 Hz.
•
The On time property specifies the time interval between samples. It
must be within the range of 4µs (20 tic s) minimum (10µs for DAS1800HR) to 64µs (320 tics) maximum. Also On time × Pulses must be
less than or equal to Period.
•
The Gate property specifies how the TGIN signal affects the operation
of the internal clock. Valid settings are Enabled, Disabled, High Level
and Low Level. See “Counter/Timer Subsystem” on page 102 for a
description of each Gate setting.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 45
Note: You cannot use a gated clock with a digital start or stop trigger.
•
The Pulses property specifies how many channels the board samples in
each Period. Pulses must equal the number of channels in the channel
list.
Also see: “Repeat Mode Sampling on the DAS-1802HR-DA” on page 57.
Burst Generator: External Clocking
An externally clocked Rate Generator produces a dual frequency clock with a fixed
number of tics at a high, internal frequency repeated at a lower, externally controlled
frequency.
Use an externally clocked burst generator when you want to synchronize a burst of
analog input samples with a recurrent external signal. In this mode you will need a
separate external clock tic for each burst of analog samples you want to acquire.
How to set up the DAS-1800 Seri es for burst mode sampling using an external clock.
BE SURE that the external
clock source is TTL
compatible, 0 V minimum to
+5 V maximum!
•
Specify external clocking using a Burst Generator on Channel 0 with
an External, External+, or External- Clock source. See
“Counter/Timer Subsystem” on page 102 for a description of clock
sources. For hardware-independence, you can specify the hardware
external clock channel by the symbolic constant, DI_EXTCLK.
•
Users should connect the external clock signal to the XPCLK line.
•
Specify a Period between the minimum and maximum exte rnal
clocking period. The value doesn’t affect the external clock frequency,
46 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
but DriverLINX requires a valid hardware value in case the application
requests a timebase operation and to optimize data transfer between the
driver and the application.
•
The On time property specifies the time interval between samples. It
must be within the range of 4µs (20 tic s) minimum (10µs for DAS1800HR) to 64µs (320 tics) maximum. Also On time × Pulses must be
less than or equal to Period.
•
The frequency of the external clock must not exceed 333 kHz.
•
The Gate property specifies how the TGIN signal affects the operation
of the internal clock. Valid settings are Enabled, Disabled, High Level
and Low Level. See “Counter/Timer Subsystem” on page 102 for a
description of each Gate setting.
Note: You cannot use a gated clock with a digital start or stop trigger.
•
The Pulses property specifies how many channels the board samples in
each Period. Pulses must equal the number of channels in the channel
list.
Also see: “Repeat Mode Sampling on the DAS-1802HR-DA” on page 57.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 47
Digital Timing Event
DriverLINX supports Digital Events as aliases for externally clocked Rate
Generators. Use this technique for compatibility with data-acquisition products that
only support external clock sources, such as some digital I/O products.
How to set up the DAS-1800 Seri es for external rate sampling using a di gi t a l event.
•
Specify external cl ocking using Channel 1. For hardware-
independence, you can specify the hardware external trigger channel by
the symbolic constant, DI_EXTCLK.
•
Users should connect the external clock signal to the XPCLK line.
•
Specify the Mask property as 1, or Bit 0, to indicate that DriverLINX
should only compare a 1-bit digital input value against the Pattern
property.
•
Specify the Match property as Not equals.
•
Specify the Pattern property as 0 for a rising, or positive, edge clock
(≠0) or 1 for a falling, or negative, edge clock (≠1).
48 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Analog Input Start Events
Start Events specify when the DAS-1800 hardware starts acquiring analog input data.
The DAS-1800 Series supports the following Start Events:
Note: The DAS-1800 Series
does not support analog
triggering.
•
None—Use this event when the DriverLINX operation does not require
a Start Event.
•
Command—DriverLINX starts the task on software command, i.e., as
soon as DriverLINX finishes programming the DAS-1800 hardware for
the task.
•
Digital—The DAS-1800 starts acquiring analog input samples when
the hardware detects the digital Logical Channel input satisfies the
condition specified in the Start Event.
None or Null Start Event
The Null Event specifies that the task does not need a Start Event to begin the task.
Command Start Event
The Command Event starts data acquisition as soon as DriverLINX has completed
programming the data-acquisition hardware with the task parameters.
Digital Start Event (Post-Triggering)
The DAS-1800 can acquire analog input samples after the hardware detects a digital
trigger condition. Use post-triggering when you want to synchronize the start of data
acquisition with an external signal.
How to set up the DAS-1800 Seri es for post-triggered analog input.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 49
Digital Start Events contain mask, pattern, and match fields. The mask is logically
ANDed with the digital input data on the Logical Channel and then compared with
the pattern for a match/mismatch.
•
Specify the Channel as 2. For hardware-independence, you can specify
the hardware external trigger channel by the symbolic constant,
DI_EXTTRG.
•
Users should connect the external trigger signal to the TGIN line.
•
Specify the Mask property as 1, or Bit 0, to indicate that DriverLINX
should only compare a 1-bit digital input value against the Pattern
property.
•
Specify the Match property as Not equals.
•
Specify the Pattern property as 0 for a rising, or positive, edge trigger
(≠0) or 1 for a falling, or negative, edge trigger (≠1).
•
Specify the Delay property as 0. The DAS-1800 does not support a
delay in sampling after the start trigger.
•
You cannot use a digital start trigger with a gated clock.
•
If both the start trigger and stop trigger are digital events, they must
have identical Pattern settings.
Digital Start Event (Gating)
The DAS-1800 can pause and resume acquiring analog input samples based on the
level of a digital input condition. Use a digital start event to set up gating when using
a digital timing event. To set up gating for a rate timing event, see “Rate Timing
Event” on page 40.
How to set up the DAS-1800 Seri es for gated analog input.
50 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Digital Start Events contain mask, pattern, and match fields. The mask selects which
bit in the Logical Channel to use as a gate input. The pattern selects whether the gate
is active, or enables data-acquisition, when the gate signal is high or low.
•
Specify the Channel as 2. For hardware-independence, you can specify
the hardware external trigger channel by the symbolic constant,
DI_EXTTRG.
•
Users should connect the external trigger signal to the TGIN line.
•
Specify the Mask property as 1, or Bit 0, to identify the gate input bit
of the Logical Channel.
•
Specify the Match property as Equals.
•
Specify the Pattern property as 0 for a low-level active gate or 1 for a
high-level active gate.
•
Specify the Delay property as 0. DriverLINX does not use a delay with
gating.
Analog Input Stop Events
Stop Events specify when the hardware stops acquiring analog input data.
The DAS-1800 Series supports the following Stop Events:
•
None—Use this event when the DriverLINX operation doesn’t require
a Stop Event.
•
Command—Dr iverLINX stops the task on software command, i.e.,
when the application issues a Service Request with a Stop operation.
•
Terminal count—DriverLINX stops the task after the data-acquisition
hardware has filled all the data buffers once.
•
Digital—The DAS-1800 stops acquiring analog input samples when
the hardware detects the digital Logical Channel input satisfies the
condition specified in the Stop Event.
None or Null Stop Event
The Null Event specifies that the task does not need a Stop Event to end the task.
Command Stop Event
The Command Event stops data acquisition when the user application changes the
Operation property in the Service Request to Stop and resubmits the Service Request
to DriverLINX.
In Stop-on-Command mode , DriverLINX continuously cycles through al l the data
buffers filling them with analog input data from the data-acquisition hardware.
Terminal Count Stop Event
The Terminal Count Event stops data acquisition after DriverLINX has filled all the
data buffers once with analog input data. Use Terminal Count when you want to
acquire a single scan or fixed amount of data.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 51
Digital Stop Event (Pre- and About-Triggering)
The DAS-1800 can acquire analog input samples until the hardware detects a digital
trigger condition. Use pre-triggering when you want to synchronize the end of data
acquisition with an external signal.
How to set up the DAS-1800 Seri es for pre-triggered analog input.
Digital Stop Events contain mask, pattern, and match fields. The mask is logically
ANDed with the digital input data on the Logical Channel and then compared with
the pattern for a match/mismatch.
•
Specify the Channel as 2. For hardware-independence, you can specify
the hardware external trigger channel by the symbolic constant,
DI_EXTTRG.
•
Users should connect the external trigger signal to the TGIN line.
•
Specify the Mask property as 1, or Bit 0, to indicate that DriverLINX
should only compare a 1-bit digital input value against the Pattern
property.
•
Specify the Match property as Not equals.
•
Specify the Pattern property as 0 for a rising, or positive, edge trigger
(≠0) or 1 for a falling, or negative, edge trigger (≠1).
•
Specify the Delay property as an integer from 0 to
2216− . The
DAS-1800 continues sampling until it obtains this number of samples
after the trigger. The number must be a multiple of the number of
channels in the channel list.
•
You cannot use a digital stop trigger with a gated clock.
•
If both the start trigger and stop trigger are digital events, they must
have identical Pattern settings.
52 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
When the hardware detects the trigger, DriverLINX sends a StopEvent message (or
event) that identifies sample following the trigger. For more information, see “Analog
Input Messages” on page 63.
Analog Input Channels
The KPCI-1800 Series models support a variety of channel gains with differential or
single-ended connections. The Logical Device configuration sets the default
connection type for analog input channels. An application can request a particular
connection type for each channel it uses. The channel gains are also application
selectable.
The DAS-1800 Series allows applications to specify the analog channels using three
techniques:
•
Start Channel—Acquire data from a single channel.
•
Start/Stop Channel Range—Acquire data from a consecutive range of
channels.
•
Channel List—Acquire data from a list of channels.
Single Channel Analog Input
In single channel mode, the DAS-1800 Series acquires all data from one channel at
the specified gain.
How to set up the DAS-1800 Seri es for sampling on a single channel.
Multi-channel Analog Input Range
In multi-channel range mode, the DAS-1800 Series acquires data from a consecutive
range of analog channels.
•
The Start Channel’s gain only applies to the first channel.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 53
•
DriverLINX uses the Stop Channel’s gain for all the other analog
channels in the range.
•
The gains may vary but they must all be either unipolar or bipolar.
•
If the Start Channel is greater than the Stop Channel, the channel
sequence is [Start Channel,… Last Channel, 0,… Stop Channel], where
Last Channel is the highest numbered channel for the DAS-1800 model
the application is using.
•
For simultaneous sampling using an SSH-8 see “Rate Generator:
Internal Cloc king” on page 41 or “Rate Generator: External Cl ocking”
on page 43.
How to set up the DAS-1800 Seri es for sampling on a consecutive range of channels.
Multi-channel Analog Input List
In multi-channel list mode, the DAS-1800 Series acquires data from an arbitrary list
of analog channels.
•
The channel-gain list may contain up to 256 channels in any order. The
list may repeat the same channel with the same or different gains.
•
The gains may vary but they must all be either unipolar or bipolar.
•
For simultaneous sampling using an SSH-8 see “Rate Generator:
Internal Cloc king” on page 41 or “Rate Generator: External Cl ocking”
on page 43.
54 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
How to set up the DAS-1800 Seri es to sample on an arbitrary list of channels.
Analog Input Channel Gains
Each channel in a channel scan list has a gain code property to select the preamplifier gain when sampling that channel. The following tables show the
correspondence between the gain multiplier, the maximum input signal range, and the
gain code for each input range. Note: DriverLINX uses a negative (-) gain multiplier
to signify a bipolar (±) range.
You should be aware that using multiple channels or non-unity gains reduces the
maximum sample rate. Consult your hardware manual for details.
DAS-1801 Models
Gain Range Gain Code
-1 ±5 V 0
-5 ±1 V 1
-50 ±100 mV 2
-250 ±20 mV 3
10 … 5 V4
50 … 1 V5
50 0 … 100 mV 6
250 0 … 20 mV 7
Gains, Ranges, and Hardware Gain Codes for DAS-1801 Models.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 55
DAS-1802 Models
Gain Range Gain Code
-1 ±10 V 0
-2 ±5 1
-4 ±2.5 V 2
-8 ±1.25 V 3
1 0 … 1 0 4
20 … 55
4 0 … 2.5 V 6
8 0 … 1.25 V 7
Gain Multipliers, Ranges, and Gain Codes for DAS-1802 Models.
Use the DriverLINX Gain2Code method to easily convert between the gains in the
above tables and Gain Codes. Using this method makes applications portable to
different hardware models that have the same analog input ranges.
Expansion Channel Gains
The available gains for an expansion channel are the products of the expansion
board’s programmable (1 and 50) and the DAS board’s programmable gains.
For example, the gains available for a channel on an EXP-1800 attached to a
DAS-1802, are: -1, -2, -4, -8, 1, 2, 4, 8, -50, -100, -200, -400, 50, 100, 200, 400.
See “Special…” on page 15 for information on configuring expansion accessories or
“Analog Input Expansion Channels” on page 58 for information on selecting
expansion channel s .
SSH-8 Channel Gains
The available gains for a channel on an SSH-8 unit are the products of the channel’s
gain on the SSH-8 and the DAS board’s programmable gains.
See “Special…” on page 15 fo r information on configuring an SSH-8 unit.
Analog Input Channel Connection Types
On the DAS-1800 Series, each Analog Input channel can use single-ended or
differential connections. When configuring the Analog Input Subsystem, you choose
a default configuration for all channels. Applications can use the default
configuration or specify the connection type for each channel it uses. This scheme
supports applications that use DAS-1800-specific features as well as those that use
only generic features.
Each channel in a channel list has a gain code property. To specify a connection type
for a channel, an application includes a connection-type flag in its gain code. The
following table shows the flag value for each connection type:
56 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Connection Type Flag Value
Default Configuration CHAN_SEDIFF_DEFAULT = 0
Single-Ended
Differential
CHAN_SEDIFF_SE =
CHAN_SEDIFF_DIFF =
13
22×
13
×
23
Note: The user chooses the default configuration on the Analog Input page of the
DriverLINX Configuration Panel. See “Configure DriverLINX Device Dialog” on
page 11.
For example, an application that requires or knows a channel’s connection type
obtains the gain code for a single-ended channel with a bipolar gain of 5, with:
Gain2Code (-5) + CHAN_SEDIFF_SE
// This code will work with only drivers that allow applications to specify a
connection type.
An application that does not require or know a channel’s connection type obtains the
gain code for a channel with a bipolar gain of 5, with:
Gain2Code (-5)
// This code will work with any board that supports bipolar ranges.
Repeat Mode Sampling on the DAS-1802HR-DA
The DAS-1802HR-DA provides an option to sample the same channel one to 4095
times before advancing to the next channel in the channel/gain queue.
To set up repeat mode sampling, choose a rate or burst timing event and set the
pulses field as follows:
Pulses Field with a Repeat Count
1 Repeat Count
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
MSB
Pulse Count
1514131211109876543210
Pulses = PULSE_REPEAT_COUNT_FLAG
+ RepeatCount × (PULSE_COUNT_MASK + 1)
AND PULSE_REPEAT_COUNT_MASK
+ PulseCount AND PULSE_COUNT_MASK
LSB
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 57
Analog Input Expansion Channels
Multiplexers can expand the number of analog input channels from the 16 base
channels up to 256 differential analog input channels (except on HC models). The
DAS-1800 Series hardware automatically switches the multiplexer channels,
allowing you to specify exp ansion channels numbers a l ong with base channels
numbers in a channel list.
To enable DriverLINX to use multiplexers, enable expansion mode in the Configure
DAS-1800 Options dialog (see Special…). With expansion mode enabled,
DriverLINX considers the board to have the original 16 base channels followed by
256 expansion channels.
DriverLINX uses a static numbering scheme for attaching multiplexers. Attaching or
removing a mux from a base channel doesn’t cha nge the Logical Channel number of
any other channel. DriverLINX r eserves a fixed numbe r of expansion cha nnels for
each potential mux, whether it is attached or not.
To determine the DriverLINX Logical Channel number for a multiplexer channel,
use the following formula or refer to the table that follows it. Note that DriverLINX
uses 0-based numbering for all channels .
<logical chan#> = <num base chan> + <base chan#> × <num mux chan> + <mux chan#>
Term Descri pti on
<logical chan#> Logical Channel number to use in channel lists.
<num base chan> Number of base channels on the DAS-1800 board
<base chan#> Base channel on the DAS-1800 board where you attached
the mux.
<num mux chan> Number of expansion channels DriverLINX reserves for
the mux. (16 for DAS-1800 expansion accessories).
<mux chan#> Channel on the expansion board where you attached the
signal. Mux channels are numbered from 0 to 15.
For example, the Logical Channel address for channel 4 on a mux attached to base
channel 3 is
16 + 3 × 16 + 4 = 68.
To specify multiplexer input channels 0, 1, and 2 on an expansion board connected to
base channel 0, use 16, 17, and 18 in the channel/gain list.
58 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Base Chan #
Mux
Chan
#
01234567etc
16 32 48 64 80 96 112 128
0
17 33 49 65 81 97 113 129
1
18 34 50 66 82 98 114 130
2
19 35 51 67 83 99 115 131
3
20 36 52 68 84 100 116 132
4
21 37 53 69 85 101 117 133
5
22 38 54 70 86 102 118 134
6
23 39 55 71 87 103 119 135
7
24 40 56 72 88 104 120 136
8
25 41 57 73 89 105 121 137
9
26 42 58 74 90 106 122 138
10
27 43 59 75 91 107 123 139
11
28 44 60 76 92 108 124 140
12
29 45 61 77 93 109 125 141
13
30 46 62 78 94 110 126 142
14
31 47 63 79 95 111 127 143
15
Table of logical channel numbers for DA S -1800 expansion boards.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 59
Analog Input Buffers
DriverLINX supports single-value, single-scan and buffered analog input.
•
For single-value input, specify the Number of buffers as 0. The buffer
for a single value is the ioValue property.
•
For single-scan input, specify the Number of buffers as 1 and the
number of Samples equal to the number of channels.
•
For buffered input, specify the Number of buffers from 1 to 255 and
the number of Samples as desired.
For example, 500 samples/2
channels = 250 is ok, but 500
samples/3 channels = 166.67
is incorrect.
How to set up the DAS-1800 Seri es to store samples in buffers.
Buffer Size
An individual DriverLINX buffer may have any size as long as the buffer length
holds an integral number of channel scans (i.e., a multiple of the number of analog
input channels you’re acquiring). This restriction enforces the requirement that all
acquired channels have the same number of sample s.
Buffer Usage
DriverLINX fills buffers sequentially until the task stops. During the task only
complete buffers are available to the application. Except for tasks that stop on
terminal count, the last buffer may be only partially full. If the task stops on a trigger,
use the StopEvent message (or event) to determine the location of the last sample.
For other cases, use a Status operation to determine the location of the last sample.
Compatibility with the KPCI-1800 Series
Keithley’s KPCI-1800 Series consists of PCI bus-based data-acquisition boards with
features similar to the DAS-1800HC models. Developers writing applications they
want to be compatible with both series should be aware of the following special
requirements for DMA mode buffering on the KPCI-1800 Series.
60 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
The KPCI-1800 Series performs direct memory access (DMA) using the PCI bus
mastering mode. To maintain the high efficiency that bus mastering provides, the
hardware transfers samples in pairs (four bytes at a time) to memory on 4-byte
boundaries. This feature has the following consequences:
•
Each buffer must have an even nu mber of samples (a multiple of four
bytes). If an application requests a DMA-mode task with an odd
number of samples per buffer, DriverLINX returns an "Invalid # of
conversions" error.
•
A sample taken on an odd-numbered clock pulse is not available until
the next even-numbered clock pulse. At high sample rates with
continuous internal or external clocking, this effect is imperceptible. At
very low sample rates, you may observe applications taking twice as
long as expected to acquire a sample. With an external clock that
produces an odd number of pulses and then stops, the application will
not receive the last sample.
Applications that require an odd number of samples per buffer or use an external
clock with an odd, finite number of clock pulses should use interrupt mode instead of
DMA mode. For existing applications that use DMA mode but do not meet these
requirements, the user can cause DriverLINX to sub stitu te interrupt mode for DMA
mode by disabling bus mastering in the KPCI-1800’s Configure DriverLINX Device
dialog.
Analog Input Data Coding
DAS-1800 Series models return Analog Input hardware codes using binary integers
for unipolar ranges and offset binary for bipolar ranges. DriverLINX refers to these
coding schemes as the “native” format.
For any programmable gain, the DAS-1800 models return hardware codes with the
ranges in the following table:
Analog Input
Resolution
Polarity Analog Input
Hardware Code
12 bits Unipolar 0 to 4095
12 bits Bipolar -2048 to 2047
(right-justified without
sign extension)
*
16 bits (HR models) Unipolar 0 to 65535
16 bits (HR models) Bipolar -32768 to 32767
Native Analog Input hardware c odes for each DAS-1800 Series polarit y.
*
The KPCI-1800 Series hardware codes are left-justified. For compatibility convert to a standard data
type with DriverLINX conversion functions.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 61
6
4
2
0
-2
-4
-6
-2048 2047
10
8
Bipolar
6
4
2
0
0 4095
DAS-1800 Series native Anal og Input Codes versus Voltage Range (except HR models).
Unipolar
DriverLINX refers to the default hardware analog-coding scheme as the “native”
format. For computer arithmetic in a higher level language, the integer, or two’s
complement, format is generally easier to use. For unipolar data, native and integer
formats are identical.
Applications can use DriverLINX’s data conversion operations to transform an entire
data buffer from native format to many common integer and floating-point formats.
62 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Analog Input Messages
For analog input operations, DriverLINX can report the following messages to the
application:
DriverLINX
Explanation
Message
Service Start DriverLINX has started the acquisition task.
Service Done DriverLINX has completed the acquisition task.
Buffer Filled DriverLINX has filled an analog input buffer.
Start Event DriverLINX has processed the interrupt for a hardware
start event.
Stop Event DriverLINX has processed the interrupt for a hardware
stop event.
Data Lost DriverLINX has detected an analog input data overrun
condition.
Critical Error DriverLINX has encountered an unexpected hardware
or software condition.
DriverLINX Event mess ages for analog input.
For detailed explanations of these messages see one of the following references:
•
DriverLINX Technical Reference Manual for C/C++ users
•
DriverLINX/VB Technical Reference Manual for VB or Delphi users
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 63
Analog Output Subsystem
The following sections describe how DriverLINX implements Analog Output
Subsystem features for the DAS-1800 Series.
Analog Output Modes
The Analog Output Subsystem supports the following modes:
•
Polled—For single-value or single-scan analog output samples.
•
Interrupt—For buffered transfers using programmed I/O.
•
DMA—For buffered transfers using direct memory access.
•
Other—For subsystem initialization and data conversion.
Analog Output Operations
The DAS-1800 Series Analog Output Subsystem supports the following DriverLINX
operations:
•
Initialize—aborts all active analog output data-acquisition tasks.
However, DriverLINX prevents one application from interfering with
another application’s data-acquisition tasks.
•
Start—initiates a data-acquisition task using the Mode, Timing, Start,
and Stop Events, the Logical Channels, and the Buffers the application
specified in the Service Request.
•
Status—reports the buffer position of the next sample that DriverLINX
will write from a buffer.
•
Stop—terminates an analog output data-acquisition task.
•
Message—DriverLINX displays a pop-up dialog box for the user
containing the text for the current DriverLINX error message.
Analog Output Pacing, Triggering and Gating Options
The DAS-1800 Series User’s Guides describe several pacing, triggering and gating
options available on DAS-1800 models. Most are available only on the DAS1800AO models. The following table summarizes these options and identifies which
Service Request properties use them. Except as indicated all tasks must use Interrupt
or DMA mode.
64 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Parameter Option Service Request Properties
Pacing Mode
Periodic (paced) Rate generator timing event
Clock Source
Software Single-value or single-scan
(Polled mode)
Internal D/A clock Rate timing event with an internal
clock source
Internal A/D clock Rate timing event with an internal
clock source. A period of 0 signifies
that the A/D task operates the clock,
which controls both tasks
External +/- Rate timing event with an external
clock source
Digital timing event
Trigger
Internal (software) Command start event
Command stop event
Terminal count stop event
Digital +/- Digital start event
Retrigger Digital start event (Interrupt mode;
task must meet certain conditions)
Gate
Level +/- Rate timing event
Digital start event (for use with a
digital timing event)
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 65
Analog Output Timing Events
Timing Events specify how the hardware paces or clocks the writing of analog output
samples. DriverLINX uses the Timing Event to program when the DAS-1800 Series
writes the next analog output sample.
The DAS-1800 Series supports the following Timing Events:
•
None—Task requires no pacing as DriverLINX is writing only a single
value or scan.
•
Rate—The DAS-1800 Series supports fixed rate writing using internal
and external clocks. You can also synchronize an Analog Output task
with an Analog Input task using a Rate Event. See “Rate Generator:
Internal Cloc king” on page 67 or “Rate Generator: External Cl ocking”
on page 69.
•
Digital—DriverLINX uses an external digital output signal to pace the
timing of the next sample.
None or Null Timing Event
The Null Event specifies that the task does not need a clock to determine when to
write the next sample.
Rate Timing Event
The DAS-1800 Series supports one type of Rate Event for analog output:
•
Rate Generator—Generates a fixed rate clock with equal time
intervals between tics.
DAS-1800 boards have a 5 MHz master clock frequency, or 0.2 µs tic period. The
16
)12(10
sample period can range from 10 tics (2µs) to
the sample rate can range from 7.63 Hz to 500 kHz.
−× tics (0.131 s). This means
66 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Rate Generator: Internal Clocking
An internally clocked Rate Generator produces a fixed rate clock with equal time
intervals between tics.
Period
Use an internally clocked rate generator when you want to write analog output
samples at equally spaced time intervals.
For hardware independence,
specify the clock channel
using the symbolic constant,
DEFAULTTIMER, which
always maps to the default
Logical Channel for analog
output timing.
How to set up the DAS-1800 Seri es for fixed rate writing using an internal clock.
•
Specify internal cl ocking using a Rate Generator on Channel 1 with
the Internal 1 Clock source. See “Counter/Timer Subsystem” on page
102 for a description of clock sources.
•
The Period property specifies the time interval between samples in tics,
where an Internal 1 tic is 0.2 µs, or 5 MHz. The minimum period is 10
tics, or 500 kHz. The maximum period is 655350 tics (
16
or 7.63 Hz.
•
The Gate property specifies how the TGIN signal affects the operation
of the internal clock. Valid settings are Enabled, Disabled, High Level
and Low Level. See “Counter/Timer Subsystem” on page 102 for a
description of each Gate setting.
Note: You cannot use a gated clock with a digital start or stop trigger.
•
Check the Simultaneous box in the Channels section. Multi-channel
analog output on the DAS-1800 Series models is always simultaneous.
)12(10
−× ),
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 67
Also see: “Synchronizing an Analog Output Task with an Analog Input Task” on
page 72.
68 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Rate Generator: External Clocki ng
An externally clocke d Rate Generator produces a rate clock with unknown time
intervals between tics.
Period (ext clk)
Use an externally clocked rate generator when you want to synchronize analog output
samples with a recurrent external signal. In this mode you will need a separate
external clock tic for each analog sample you want to write.
How to set up the DAS-1800 Seri es for fixed rate sampling using an external clock.
Be sure that the external
clock source is TTL
compatible, 0 V minimum to
+5 V maximum!
•
Specify external clocking using a Rate Generator on Channel 1 with
an External, External+, or External- Clock source. See
“Counter/Timer Subsystem” on page 102 for a description of clock
sources. For hardware-independence, you can specify the hardware
external clock channel by the symbolic constant, DI_EXTCLK.
•
Users should connect the external clock signal to the XPCLK line.
•
Specify a Period between the minimum and maximum exte rnal
clocking period. The value doesn’t affect the external clock frequency,
but DriverLINX requires a valid hardware value in case the application
requests a timebase operation and to optimize data transfer between the
driver and the application.
•
The frequency of the external clock must not exceed 500 kHz.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 69
•
The Gate property specifies how the TGIN signal affects the operation
of the internal clock. Valid settings are Enabled, Disabled, High Level
and Low Level. See “Counter/Timer Subsystem” on page 102 for a
description of each Gate setting.
Note: You cannot use a gated clock with a digital start or stop trigger.
•
Check the Simultaneous box in the Channels section. Multi-channel
analog output on the DAS-1800 Series models is always simultaneous.
Also see: “Synchronizing an Analog Output Task with an Analog Input Task” on
page 72.
70 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Digital Timing Event
DriverLINX supports Digital Events as aliases for externally clocked Rate
Generators. Use this technique for compatibility with data-acquisition products that
only support external clock sources, such as some digital I/O products.
How to set up the DAS-1800 Seri es for external rate sampling using a di gi t a l event.
•
Specify external cl ocking using Channel 1. For hardware-
independence, you can specify the hardware external trigger channel by
the symbolic constant, DI_EXTCLK.
•
Users should connect the external clock signal to the XPCLK line.
•
Specify the Mask property as 1, or Bit 0, to indicate that DriverLINX
should only compare a 1-bit digital input value against the Pattern
property.
•
Specify the Match property as Not equals.
•
Specify the Pattern property as 0 for a rising, or positive, edge clock
(≠0) or 1 for a falling, or negative, edge clock (≠1).
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 71
Synchronizing an Analog Output Task with an Analog Input Task
On the DAS-1800 Series, DriverLINX can synchronize an analog output task with an
analog input task. The analog output task uses the same timing event as the input
task.
To synchronize an analog output (AO) task with an analog input (AI) task:
1. Set up the AI service request.
2. Set up the AO service request using an identical timing event as the AI
task, except with set the Period to zero. Both the AI and AO timing
event must use Counter/Timer channel 0.
3. Submit the AO service request. The hardware runs the AO task only
while the AI task is running.
4. Submit the AI service request to start both tasks.
Although both tasks shar e the same clock source , they are otherwise logically
independent of each other. Your application must manage and respond to each task
separately. If the AI task terminates before the AO task, the AO task will still be
logically active, but the clock stop sending timing pulses to the AO task until the next
AI task starts. If you want to terminate the AO task when the AI task stops, either set
up both service requests with equal buffer sizes and Stop Events, or issue a Stop
operation request for the AO task.
Analog Output Start Events
Start Events specify when the DAS-1800 hardware starts acquiring analog output
data.
The DAS-1800 Series supports the following Start Events:
•
None—Use this event when the DriverLINX operation does not require
a Start Event.
•
Command—DriverLINX starts the task on software command, i.e., as
soon as DriverLINX finishes programming the DAS-1800 hardware for
the task.
•
Digital—The DAS-1800 starts acquiring analog output samples when
the hardware detects the digital Logical Channel output satisfies the
condition specified in the Start Event.
None or Null Start Event
The Null Event specifies that the task does not need a Start Event to begin the task.
Command Start Event
The Command Event starts data acquisition as soon as DriverLINX has completed
programming the data-acquisition hardware with the task parameters.
Digital Start Event (Post-Triggering)
The DAS-1800 can write analog output samples after the hardware detects a digital
trigger condition. Use post-triggering when you want to synchronize the start of data
acquisition with an external signal.
72 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
How to set up the DAS-1800 Seri es for post-triggered analog output.
Digital Start Events contain mask, pattern, and match fields. The mask is logically
ANDed with the digital input data on the Logical Channel and then compared with
the pattern for a match/mismatch.
•
Specify the Channel as 2. For hardware-independence, you can specify
the hardware external trigger channel by the symbolic constant,
DI_EXTTRG.
•
Users should connect the external trigger signal to the TGIN line.
•
Specify the Mask property as 1, or Bit 0, to indicate that DriverLINX
should only compare a 1-bit digital input value against the Pattern
property.
•
Specify the Match property as Not equals.
•
Specify the Pattern property as 0 for a rising, or positive, edge trigger
(≠0) or 1 for a falling, or negative, edge trigger (≠1).
•
Specify the Delay property as 0. The DAS-1800 does not support a
delay in sampling after the start trigger.
•
You cannot use a digital start trigger with a gated clock.
Digital Start Event (Gating)
The DAS-1800 can pause and resume writing analog output samples based on the
level of a digital input condition. Use a digital start event to set up gating when using
a digital timing event. To set up gating for a rate timing event, see “Rate Timing
Event” on page 66.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 73
How to set up the DAS-1800 Seri es for gated analog output.
Digital Start Events contain mask, pattern, and match fields. The mask selects which
bit in the Logical Channel to use as a gate input. The pattern selects whether the gate
is active, or enables data-acquisition, when the gate signal is high or low.
•
Specify the Channel as 2. For hardware-independence, you can specify
the hardware external trigger channel by the symbolic constant,
DI_EXTTRG.
•
Users should connect the external trigger signal to the TGIN line.
•
Specify the Mask property as 1, or Bit 0, to identify the gate input bit
of the Logical Channel.
•
Specify the Match property as Equals.
•
Specify the Pattern property as 0 for a low-level active gate or 1 for a
high-level active gate.
•
Specify the Delay property as 0. DriverLINX does not use a delay with
gating.
Digital Start Event (Retriggering)
In recycle mode, a DAS-1800AO continuously writes analog output samples from its
FIFO buffer. A digital trigger can restart the output at the beginning of the FIFO
buffer. Use retriggering when you want to repeatedly synchronize the start of a
waveform output with an external signal.
To use recycle mode, the device configuration must enable it and the task must meet
certain conditions. See “Special…” on page 15 for more information.
74 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
How to set up the DAS-1800 Seri es for post-triggered analog output.
Digital Start Events contain mask, pattern, and match fields. The mask is logically
ANDed with the digital input data on the Logical Channel and then compared with
the pattern for a match/mismatch.
•
Specify the Channel as 2. For hardware-independence, you can specify
the hardware external trigger channel by the symbolic constant,
DI_EXTTRG.
•
Users should connect the external trigger signal to the TGIN line.
•
Specify the Mask property as 1, or Bit 0, to indicate that DriverLINX
should only compare a 1-bit digital input value against the Pattern
property.
•
Specify the Match property as Not equals.
•
Specify the Pattern property as 0 for a rising, or positive, edge trigger
(≠0) or 1 for a falling, or negative, edge trigger (≠1).
•
Specify the Delay property as 0. The DAS-1800 does not support a
delay in sampling after the start trigger.
•
You cannot use a digital start trigger with a gated clock.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 75
Analog Output Stop Events
Stop Events specify when the hardware stops acquiring analog output data.
The DAS-1800 Series supports the following Stop Events:
•
None—Use this event when the DriverLINX operation doesn’t require
a Stop Event.
•
Command—Dr iverLINX stops the task on software command, i.e.,
when the application issues a Service Request with a Stop operation.
•
Terminal count—DriverLINX stops the task after the data-acquisition
hardware has filled all the data buffers once.
None or Null Stop Event
The Null Event specifies that the task does not need a Stop Event to end the task.
Command Stop Event
The Command Event stops data acquisition when the user application changes the
Operation property in the Service Request to Stop and resubmits the Service Request
to DriverLINX.
In Stop-on-Command mode , DriverLINX continuously cycles through al l the data
buffers the analog output data to the data-acquisition hardware.
Terminal Count Stop Event
The Terminal Count Event stops data acquisition after DriverLINX has filled all the
data buffers once with analog output data. Use Terminal Count when you want to
write a single scan or fixed amount of data.
76 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Analog Output Channels
The DAS-1800 Series allows applications to specify the analog channels using three
techniques:
•
Start Channel—Write data to a single channel.
•
Start/Stop Channel Range—Write da ta to a consecutive range of
channels.
•
Channel List—Write data to a list of channels.
Single Channel Analog Output
In single channel mode, the DAS-1800 Series writes all data to one channel at the
specified gain.
How to set up the DAS-1800 Seri es for writing to sampling on a si ngl e channel.
Multi-channel Analog Output Range
In multi-channel range mode, the DAS-1800 Series writes data to a consecutive range
of analog channels.
•
The Start Channel’s gain only applies to the first channel.
•
DriverLINX uses the Stop Channel’s gain for all the other analog
channels in the range.
•
The Stop Channel must be greater than the Start Channel.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 77
How to set up the DAS-1800 Seri es for writing to a consec utive range of channels.
Multi-channel Analog Output List
In multi-channel list mode, the DAS-1800 Series writes data to an arbitrary list of
analog channels.
•
The channel-gain list may contain up to channels in any order and with
any allowed gain but may repeat any channel.
How to set up the DAS-1800 Seri es to write to an arbitrary li st of channels.
78 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Analog Output Channel Gains
The DAS-1800 Series models support a variety of channel gains. The following table
shows the correspondence between DriverLINX gains, the maximum output signal
range, and the gain code for each output range. Note: DriverLINX uses a negative (-)
gain value to signify a b i polar (±) range.
AO Models
Gain Range Gain Code
-1 ±5 V 0
-0.5 ±10 V 1
Gains, Ranges, and Gain Codes for A O M odel s.
HC and DA Models
Gain Range Gain Code
-1 ±10 V 0
Gains, Ranges, and Gain Codes for HC and DA Models.
Use the DriverLINX Gain2Code method to easily convert between the gains in the
above tables and hardware Gain Codes.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 79
Analog Output Buffers
DriverLINX supports single-value, single-scan and buffered analog output.
•
For single-value output, specify the Number of buffers as 0. The
buffer for a single value is the ioValue property.
•
For a single-scan output, specify the Number of buffers as 1 and the
number of Samples equal to the number of channels.
•
For buffered output, specify the Number of buffers from 1 to 255 and
the number of Samples as desired.
For example, 500 samples/2
channels = 250 is ok, but 500
samples/3 channels = 166.67
is incorrect.
How to set up the DAS-1800 Seri es to store samples in buffers.
Buffer Size
An individual DriverLINX buffer may have any size as long as the buffer length
holds an integral number of channel scans (i.e., a multiple of the number of analog
output channels you’re acquiring). This restriction enforces the requirement that all
acquired channels have the same number of sample s.
Buffer Usage
DriverLINX writes from buffers sequentially until the task stops. Except for tasks
that stop on terminal count, the last buffer may be only partially used. If the task
stops on a trigger, use the StopEvent message (or event) to determine the location of
the last sample. For other cases, use a Status operation to determine the location of
the last sample.
80 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Analog Output Data Coding
DAS-1800 Series models use a variety of formats to encode analog output data, as
shown in the following table. DriverLINX refers to these coding schemes as the
“native” format.
Model Format Analog
Output
Resolution
AO,
ST-DA
HC Offset binary 12 bits 0 to 4095
HR-DA Two’s complement 16 bits -32768 to 32767
Two’s complement, right-shifted 12 bits -2048 to 2047
Native Analog Output hardware c odes for each DAS-1800 Series resolution.
Analog Output
Hardware
Code
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 81
6
4
2
0
-2048 2047
-2
-4
-6
6
4
2
0
0 4095
-2
-4
-6
6
4
2
0
-32768 32767
-2
AO, ST-DA
HC
HR
-4
-6
DAS-1800 Series native Anal og Output Codes versus Voltage Range at unity gain.
DriverLINX refers to the default hardware analog-coding scheme as the “native”
format. For computer arithmetic in a hi gher level language, the 16-bit two’s
complement integer format is generally easier to use.
DriverLINX automatically converts digital-to-analog codes to integer format, if you
specify integer for the Format property. Or, applications can use DriverLINX’s data
conversion operations to transform an entire data buffer from many common integer
and floating-point formats to native format.
82 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Analog Output Messages
For analog output operations, DriverLINX can report the following messages to the
application:
DriverLINX
Explanation
Message
Service Start DriverLINX has started the acquisition task.
Service Done DriverLINX has completed the acquisition task.
Buffer Filled DriverLINX has filled an analog output buffer.
Critical Error DriverLINX has encountered an unexpected hardware
or software condition.
DriverLINX Event mess ages for analog output.
For detailed explanations of these messages see one of the following references:
•
DriverLINX Technical Reference Manual for C/C++ users
•
DriverLINX/VB Technical Reference Manual for VB or Delphi users
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 83
Digital Input Subsystem
The following sections describe how DriverLINX implements Digital Input
Subsystem features for the DAS-1800 Series.
Digital Input Modes
The Digital Input Subsystem supports the following modes:
•
Polled—For single-value digital input samples.
•
Interrupt—For buffered transfers using programmed I/O.
•
Other—For subsystem initialization.
Digital Input Operations
The DAS-1800 Series Digital Input Subsystem supports the following DriverLINX
operations:
•
Initialize—aborts any active interrupt data-acquisition tasks and stops
•
Start—initiates a data-acquisition task using the Mode, Timing, Start,
the clock. DriverLINX prevents one application from interfering with
another application’s data-acquisition tasks.
and Stop Events, the Logical Channels, and the Buffers the application
specified in the Service Request.
•
Status—reports the buffer position of the next sample that DriverLINX
will write into a buffer.
•
Stop—terminates an analog output data-acquisition task.
•
Message—DriverLINX displays a pop-up dialog box for the user
containing the text for the current DriverLINX error message.
Digital Port Configuration
The DAS-1800 Series has separate, dedicated digital input and output ports and
doesn’t require the application to configure its digital I/O ports.
Digital Input Pacing, Tr i ggering and Gating Options
The DAS-1800 Series User’s Guides describe several pacing, triggering and gating
options available for analog input on DAS-1800 models. As DriverLINX uses the
analog input pacer clock for digital input, many of these options also apply to digital
input tasks. The following table summarizes these options and identifies which
Service Request properties use them. Except as indicated all tasks must use Interrupt
or DMA mode.
84 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Parameter Option Service Request Properties
Pacing Mode
Periodic (paced) Rate generator timing event
Clock Source
Software Single-value or single-scan
(Polled mode)
Internal Rate timing event with an internal
clock source
External +/- Rate timing event with an external
clock source
Digital timing event
Trigger
Internal (software) Command start event
Command stop event
Terminal count stop event
Digital Input Timing Events
Timing Events specify how the hardware paces or clocks the reading of Digital Input
samples. DriverLINX uses the Timing Event to program when the DAS-1800 Series
reads the next digital input sample from the port.
The DAS-1800 Series supports the following Timing Events:
•
None—Input requires no pacing as DriverLINX i s reading only a single
value.
•
Rate—The DAS-1800 Series supports fixed rate writing using internal
and external clocks.
None or Null Timing Event
The Null Event specifies that the task does not need a clock to determine when to
read the next sample.
Rate Timing Event
The DAS-1800 Series supports one type of Rate Event for digital output:
•
Rate Generator—Generates a fixed rate clock with equal time
intervals between tics.
DAS-1800 boards have a 5 MHz master clock frequency, or 0.2 µs tic period. The
sample period can range from 500 tics (100 µs) to
the sample rate can range from 0.00116 Hz to 10kHz.
32
21
− tics (833 s). This means
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 85
Rate Generator: Internal Clocking
An internally clocked Rate Generator produces a fixed rate clock with equal time
intervals between tics.
Period
Use an internally clocked rate generator when you want to write digital output
samples at equally spaced time intervals.
For hardware independence,
specify the clock channel
using the symbolic constant,
DEFAULTTIMER, which
always maps to the default
Logical Channel for digital
output timing.
How to set up the DAS-1800 Seri es for fixed rate sampling using an i nt ernal clock.
•
Specify internal cl ocking using a Rate Generator on Channel 0 with
the Internal 1 Clock source. See “Counter/Timer Subsystem” on page
102 for a description of clock sources.
•
The Period property specifies the time interval between samples in tics,
where an Internal 1 tic is 0.2 µs, or 5 MHz. The minimum period is
500 tics, or 10 kHz. The maximum period is 4294967295 tics (
21
or 0.00116 Hz.
•
Digital input does not support gating. Set the Gate property to
Disabled or NoConnect.
32
− ),
86 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Digital Input Start Events
Start Events specify when the DAS-1800 Series hardware starts reading digital input
data.
The DAS-1800 Series supports the following Start Events for digital input:
•
None—Use this event when the DriverLINX operation doesn’t require
a Start Event.
•
Command—DriverLINX starts the task on software command, i.e., as
soon as DriverLINX finishes programming the DAS-1800 hardware for
the task.
None or Null Start Event
The Null Event specifies that the task does not need a Start Event to begin the task.
Command Start Event
The Command Event starts data acquisition as soon as DriverLINX has completed
programming the DAS-1800 Series hardware with the task parameters.
Digital Input Stop Events
Stop Events specify when the DAS-1800 Series hardware stops reading digital input
data.
The DAS-1800 Series supports the following Stop Events for digital input:
•
None—Use this event when the DriverLINX operation doesn’t require
a Stop Event.
•
Command—Dr iverLINX stops the task on software command, i.e.,
when the application issues a Service Request with a Stop operation.
•
Terminal count—DriverLINX stops the task after the DAS-1800
Series hardware has filled all the data buffers once.
None or Null Stop Event
The Null Event specifies that the task does not need a Stop Event to end the task.
Command Stop Event
The Command Event stops data acquisition when the user application changes the
Operation property in the Service Request to Stop and resubmits the Service Request
to DriverLINX.
In Stop-on-Command mode , DriverLINX continuously cycles through al l the data
buffers, reading from the digital port on the DAS-1800 Series.
Terminal Count Stop Event
The Terminal Count Event stops data acquisition after DriverLINX has read the
digital input data into all the data buffers once. Use terminal count when you want to
read a fixed amount of data.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 87
Digital Input Channels
The DAS-1800 Series allows applications to specify the digital channels using three
techniques:
•
Start Channel—Acquire data from a single channel.
•
Start/Stop Channel Range—Acquire data from a consecutive range of
channels.
•
Channel List—Acquire data from a list of channels.
Digital Input Logical Channels
The DAS-1800 Series has a single digital input port that DriverLINX designates as
Logical Channel 0. DriverLINX defines two additional Logical Channels for the
external clock and trigger signals but applications cannot directly read their values.
DriverLINX defines the following Logical Channels for the DAS-1800 Series digital
inputs:
Logical
Channel
0 Standard Digital Input DI 0 … DI 3
1 External Clock XPCLK
2 External Trigge r TGIN
DriverLINX Function DAS-1800 Series
External Connector
Single Channel Digital Input
In single channel mode, the DAS-1800 Series acquires all data from one channel.
How to set up the DAS-1800 Seri es to read from a single channel.
88 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Multi-channel Digital Input Range
Even though the DAS-1800
Series has only one digital
input channel, DriverLINX
supports specifying a channel
range for compatibility with
applications that use this
method.
In multi-channel range mode, the DAS-1800 Series acquires all data from a
consecutive range of digital channels.
•
Both the Start and Stop Channel must specify channel 0.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 89
Multi-channel Digital Input List
Even though the DAS-1800
Series has only one digital
input channel, DriverLINX
supports specifying a channel
range for compatibility with
applications that use this
method
In multi-channel list mode, the DAS-1800 Series acquires all data from a random list
of digital channels.
•
The channel list may contain only one channel.
•
As the DAS-1800 Series only has a single digital input channel
available fo r reading, this technique is equival ent to Single Channel
Digital Input.
Digital Input Buffers
DriverLINX supports single-value, single-scan and buffered digital input.
•
For single-value input, specify the Number of buffers as 0. The buffer
for a single value is the ioValue property.
•
For single-scan input, specify the Number of buffers as 1 and the
number of Samples equal to the number of channels.
•
For buffered input, specify the Number of buffers from 1 to 255 and
the number of Samples as desired.
90 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
How to set up the DAS-1800 Seri es to read digital samples using dat a buf fers.
Buffer Usage
DriverLINX fills buffers sequentially until the task stops. During the task only
complete buffers are available to the application. Except for tasks that stop on
terminal count, the last buffer may be only partially full. If the task stops on a trigger,
use the StopEvent message (or event) to determine the location of the last sample.
For other cases, use a Status operation to determine the location of the last sample.
Digital Input Messages
For digital input operations, DriverLINX can report the following messages to the
application:
DriverLINX
Explanation
Message
Service Start DriverLINX has started the acquisition task.
Service Done DriverLINX has completed the acquisition task.
Buffer Filled DriverLINX has filled a digital input buffer.
Critical Error DriverLINX has encountered an unexpected hardware
or software condition.
DriverLINX Event mess ages for digital input.
For detailed explanations of these messages see one of the following references:
•
DriverLINX Technical Reference Manual for C/C++ users
•
DriverLINX/VB Technical Reference Manual for VB or Delphi users
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 91
92 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Digital Output Subsystem
The following sections describe how DriverLINX implements Digital Output
Subsystem features for the DAS-1800 Series.
Digital Output Modes
The Digital Output Subsystem supports the following modes:
•
Polled—For single-value digital output samples.
•
Interrupt—For buffered transfers using programmed I/O.
•
Other—For subsystem initialization.
Digital Output Operations
The DAS-1800 Series Digital Output Subsystem supports the following DriverLINX
operations:
•
Initialize—aborts any active interrupt data-acquisition tasks and stops
the clock. DriverLINX prevents one application from interfering with
another application’s data-acquisition tasks.
•
Start—initiates a data-acquisition task using the Mode, Timing, Start,
and Stop Events, the Logical Channels, and the Buffers the application
specified in the Service Request.
•
Status—reports the buffer position of the next sample that DriverLINX
will write from a buffer.
•
Stop—terminates an digital output data-acquisition task.
•
Message—DriverLINX displays a pop-up dialog box for the user
containing the text for the current DriverLINX error message.
Digital Output Initialization
By default, the Digital Output subsystem writes zero into the digital output port. You
can specify a different initial output value using the Configure DriverLINX Device
dialog. See “Digital Output Subsystem Page” on page 24.
Digital Output Pacing, Triggering and Gating Options
The DAS-1800 Series User’s Guides describe several pacing, triggering and gating
options available for analog input on DAS-1800 models. As DriverLINX uses the
analog input pacer clock for digital output, many of these options also apply to digital
output tasks. The following table summarizes these options and identifies which
Service Request properties use them. Except as indicated all tasks must use Interrupt
or DMA mode.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 93
Parameter Option Service Request Properties
Pacing Mode
Periodic (paced) Rate generator timing event
Clock Source
Software Single-value or single-scan
(Polled mode)
Internal Rate timing event with an internal
clock source
External +/- Rate timing event with an external
clock source
Digital timing event
Trigger
Internal (software) Command start event
Command stop event
Terminal count stop event
Digital Output Timing Events
Timing Events specify how the hardware paces or clocks writing Digital Output
samples. DriverLINX uses the Timing Event to program when the DAS-1800 Series
writes the next digital output sample from the port.
The DAS-1800 Series supports the following Timing Events:
•
None—Output requires no pacing as DriverLINX is writing only a
single value.
•
Rate—The DAS-1800 Series supports fixed rate writing using internal
and external clocks.
None or Null Timing Event
The Null Event specifies that the task does not need a clock to determine when to
write the next sample.
94 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Rate Timing Event
The DAS-1800 Series supports one type of Rate Event for digital output:
•
Rate Generator—Generates a fixed rate clock with equal time
intervals between tics.
DAS-1800 boards have a 5 MHz master clock frequency, or 0.2 µs tic period. The
sample period can range from 500 tics (100 µs) to
32
21
− tics (833 s). This means
the sample rate can range from 0.00116 Hz to 10kHz.
Rate Generator: Internal Clocking
An internally clocked Rate Generator produces a fixed rate clock with equal time
intervals between tics.
Period
Use an internally clocked rate generator when you want to write digital output
samples at equally spaced time intervals.
How to set up the DAS-1800 Seri es for fixed rate writing using an internal clock.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 95
For hardware independence,
specify the clock channel
using the symbolic constant,
DEFAULTTIMER, which
always maps to the default
Logical Channel for digital
output timing.
•
Specify internal cl ocking using a Rate Generator on Channel 0 with
the Internal 1 Clock source. See “Counter/Timer Subsystem” on page
102 for a description of clock sources.
•
The Period property specifies the time interval between samples in tics,
where an Internal 1 tic is 0.2 µs, or 5 MHz. The minimum period is
500 tics, or 10 kHz. The maximum period is 4294967295 tics (
32
21
or 0.00116 Hz.
•
Digital output does not support gating. Set the Gate property to
Disabled or NoConnect.
− ),
96 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Digital Output Start Events
Start Events specify when the DAS-1800 Series hardware starts writing digital output
data.
The DAS-1800 Series supports the following Start Events for digital output:
•
None—Use this event when the DriverLINX operation doesn’t require
a Start Event.
•
Command—DriverLINX starts the task on software command, i.e., as
soon as DriverLINX finishes programming the DAS-1800 hardware for
the task.
None or Null Start Event
The Null Event specifies that the task does not need a Start Event to begin the task.
Command Start Event
The Command Event starts data acquisition as soon as DriverLINX has completed
programming the DAS-1800 hardware with the task parameters.
Digital Output Stop Events
Stop Events specify when the DAS-1800 Series hardware stops writing digital output
data.
The DAS-1800 Series supports the following Stop Events for digital output:
•
None—Use this event when the DriverLINX operation doesn’t require
a Stop Event.
•
Terminal count—DriverLINX stops the task after the DAS-1800
Series hardware has written all the data buffers once.
None or Null Stop Event
The Null Event specifies that the task does not need a Stop Event to end the task.
Terminal Count Stop Event
The Terminal Count Event stops data acquisition after DriverLINX has written the
digital output data from all the data buffers once. Use terminal count when you want
to write a fixed amount of data.
Digital Output Channels
The DAS-1800 Series allows applications to specify the digital channels using three
techniques:
•
Start Channel—Acquire data from a single channel.
•
Start/Stop Channel Range—Acquire data from a consecutive range of
channels.
•
Channel List—Acquire data from a list of channels.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 97
Digital Output Logical Channels
The DAS-1800 Series has one digital output port that DriverLINX designates as
channel 0. And, expect on HC models, DriverLINX designates the MUX and GEXT
signal as another, 5-bit, digital output channel.
Logical Channel DriverLINX
Function
0 (HC models) Standard Digital Output DO 0 … DO 7
0 (except HC models) Standard Digital Output DO 0 … DO 3
1 (except HC models) Standard Digital Output MUX4 … MUX7, GEXT
DAS-1800 Series
External Connector
Single Channel Digital Output
In single channel mode, the DAS-1800 Series writes all data from one channel.
How to set up the DAS-1800 Seri es to write a single digital out put channel.
Multi-channel Digital Output Range
In multi-channel range mode, the DAS-1800 Series acquires all data from a
consecutive range of digital channels.
•
The Start and Stop Channel must specify the same channel as
DriverLINX supports only single value output in the digital output
subsystem.
98 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
Multi-channel Digital Output List
In multi-channel list mode, the DAS-1800 Series acquires all data from a random list
of digital channels.
•
The channel list may contain only one channel as DriverLINX supports
only single value output in the digital output subsystem.
Keithley DAS-1800 Series Using the DAS-1800 Series with DriverLINX • 99
Digital Output Buffers
DriverLINX supports single-value, single-scan and buffered digital output.
•
For single-value output, specify the Number of buffers as 0. The
buffer for a single value is the ioValue property.
•
For a single-scan output, specify the Number of buffers as 1 and the
number of Samples equal to the number of channels.
•
For buffered output, specify the Number of buffers from 1 to 255 and
the number of Samples as desired.
For example, 500 samples/2
channels = 250 is ok, but 500
samples/3 channels = 166.67
is incorrect.
How to set up the DAS-1800 Seri es to store samples in buffers.
Buffer Size
An individual DriverLINX buffer may have any size as long as the buffer length
holds an integral number of channel scans (i.e., a multiple of the number of digital
output channels you’re acquiring). This restriction enforces the requirement that all
acquired channels have the same number of sample s.
Buffer Usage
DriverLINX writes from buffers sequentially until the task stops. Except for tasks
that stop on terminal count, the last buffer may be only partially used. If the task
stops on a trigger, use the StopEvent message (or event) to determine the location of
the last sample. For other cases, use a Status operation to determine the location of
the last sample.
100 • Using the DAS-1800 Series with DriverLINX Keithley DAS-1800 Series
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