Keithley 7020 Service Manual
Model 7020 Digital I/O Interface Card
Instruction Manual
A GREATER MEASURE OF CONFIDENCE
W ARRANTY
Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of 1 year
from date of shipment.
Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable
batteries, diskettes, and documentation.
During the warranty period, we will, at our option, either repair or replace any product that proves to be defective.
To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in Cleveland, Ohio.
You will be given prompt assistance and return instructions. Send the product, transportation prepaid, to the indicated service
facility . Repairs will be made and the product returned, transportation prepaid. Repaired or replaced products are warranted for
the balance of the original warranty period, or at least 90 days.
LIMIT A TION OF W ARRANTY
This warranty does not apply to defects resulting from product modification without Keithley’s express written consent, or
misuse of any product or part. This warranty also does not apply to fuses, software, non-rechargeable batteries, damage from
battery leakage, or problems arising from normal wear or failure to follow instructions.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY
IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES.
NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT,
INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS
INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE
OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY
PERSON, OR DAMAGE TO PROPERTY.
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4/01
Model 7020 Digital I/O Interface Card
Instruction Manual
©1995, Keithley Instruments, Inc.
All rights reserved.
Cleveland, Ohio, U.S.A.
Second Printing, March 2001
Document Number: 7020-901-01 Rev. B
Manual Print History
The print history shown below lists the printing dates of all Revisions and Addenda created for this manual. The
Revision Level letter increases alphabetically as the manual undergoes subsequent updates. Addenda, which are
released between Revisions, contain important change information that the user should incorporate immediately into
the manual. Addenda are numbered sequentially. When a new Revision is created, all Addenda associated with the
previous Revision of the manual are incorporated into the new Revision of the manual. Each new Revision includes
a revised copy of this print history page.
Revision A (Document Number 7020-901-01)....................................................................................... April 1995
Addendum A (Document Number 7020-901-02)................................................................................... April 1998
Revision B (Document Number 7020-901-01)..................................................................................... March 2001
All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.
Other brand and product names are trademarks or registered trademarks of their respective holders.
Safety Precautions
The following safety precautions should be observed before using
this product and any associated instrumentation. Although some instruments and accessories would normally be used with non-hazardous voltages, there are situations where hazardous conditions
may be present.
This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury. Read the operating information
carefully before using the product.
The types of product users are:
Responsible body
and maintenance of equipment, for ensuring that the equipment is
operated within its specifications and operating limits, and for ensuring that operators are adequately trained.
Operators
trained in electrical safety procedures and proper use of the instrument. They must be protected from electric shock and contact with
hazardous live circuits.
Maintenance personnel
to keep it operating, for example, setting the line voltage or replacing consumable materials. Maintenance procedures are described in
the manual. The procedures explicitly state if the operator may perform them. Otherwise, they should be performed only by service
personnel.
Service personnel
safe installations and repairs of products. Only properly trained service personnel may perform installation and service procedures.
Keithley products are designed for use with electrical signals that
are rated Installation Category I and Installation Category II, as described in the International Electrotechnical Commission (IEC)
Standard IEC 60664. Most measurement, control, and data I/O signals are Installation Category I and must not be directly connected
to mains voltage or to voltage sources with high transient over-voltages. Installation Category II connections require protection for
high transient over-voltages often associated with local AC mains
connections. The user should assume all measurement, control, and
data I/O connections are for connection to Category I sources unless otherwise marked or described in the Manual.
is the individual or group responsible for the use
use the product for its intended function. They must be
perform routine procedures on the product
are trained to work on live circuits, and perform
Exercise extreme caution when a shock hazard is present. Lethal
voltage may be present on cable connector jacks or test fixtures. The
American National Standards Institute (ANSI) states that a shock
hazard exists when voltage levels greater than 30V RMS, 42.4V
peak, or 60VDC are present.
that hazardous voltage is present in any unknown circuit before
measuring.
Users of this product must be protected from electric shock at all
times. The responsible body must ensure that users are prevented
access and/or insulated from every connection point. In some cases,
connections must be exposed to potential human contact. Product
users in these circumstances must be trained to protect themselves
from the risk of electric shock. If the circuit is capable of operating
at or above 1000 volts,
exposed.
Do not connect switching cards directly to unlimited power circuits.
They are intended to be used with impedance limited sources.
NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective devices to limit fault current and voltage to the card.
Before operating an instrument, make sure the line cord is connected to a properly grounded power receptacle. Inspect the connecting
cables, test leads, and jumpers for possible wear, cracks, or breaks
before each use.
When installing equipment where access to the main power cord is
restricted, such as rack mounting, a separate main input power disconnect device must be provided, in close proximity to the equipment and within easy reach of the operator.
For maximum safety, do not touch the product, test cables, or any
other instruments while power is applied to the circuit under test.
ALWAYS remove power from the entire test system and discharge
any capacitors before: connecting or disconnecting cables or jumpers, installing or removing switching cards, or making internal
changes, such as installing or removing jumpers.
Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth) ground. Always
make measurements with dry hands while standing on a dry, insulated
surface capable of withstanding the voltage being measured.
A good safety practice is to expect
no conductive part of the circuit may be
The instrument and accessories must be used in accordance with its
specifications and operating instructions or the safety of the equipment may be impaired.
Do not exceed the maximum signal levels of the instruments and accessories, as defined in the specifications and operating information, and as shown on the instrument or test fixture panels, or
switching card.
When fuses are used in a product, replace with same type and rating
for continued protection against fire hazard.
Chassis connections must only be used as shield connections for
measuring circuits, NOT as safety earth ground connections.
If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation requires the use of a
lid interlock.
If a screw is present, connect it to safety earth ground using the
wire recommended in the user documentation.
!
The symbol on an instrument indicates that the user should refer to the operating instructions located in the manual.
The symbol on an instrument shows that it can source or measure 1000 volts or more, including the combined effect of normal
and common mode voltages. Use standard safety precautions to
avoid personal contact with these voltages.
The
WARNING
result in personal injury or death. Always read the associated information very carefully before performing the indicated procedure.
The
CAUTION
damage the instrument. Such damage may invalidate the warranty.
Instrumentation and accessories shall not be connected to humans.
Before performing any maintenance, disconnect the line cord and
all test cables.
To maintain protection from electric shock and fire, replacement
components in mains circuits, including the power transformer, test
leads, and input jacks, must be purchased from Keithley Instruments. Standard fuses, with applicable national safety approvals,
may be used if the rating and type are the same. Other components
that are not safety related may be purchased from other suppliers as
long as they are equivalent to the original component. (Note that selected parts should be purchased only through Keithley Instruments
to maintain accuracy and functionality of the product.) If you are
unsure about the applicability of a replacement component, call a
Keithley Instruments office for information.
To clean an instrument, use a damp cloth or mild, water based
cleaner. Clean the exterior of the instrument only. Do not apply
cleaner directly to the instrument or allow liquids to enter or spill
on the instrument. Products that consist of a circuit board with no
case or chassis (e.g., data acquisition board for installation into a
computer) should never require cleaning if handled according to instructions. If the board becomes contaminated and operation is affected, the board should be returned to the factory for proper
cleaning/servicing.
heading in a manual explains dangers that might
heading in a manual explains hazards that could
2/01
DIGITAL I/O CAPABILITY: Forty independent inputs.
Forty independent outputs.
OUTPUT SPECIFICATIONS:
Configuration: 40 open collector drivers with factory installed
10kΩ pull up resistors. Pull-up resistors can be removed when
driving external pull-up devices. Each driver has an internal flyback diode.
Pull up Voltage: 5.3V Internally supplied, external connection pro-
vided for user supplied voltage 25V max. Removal of internal
jumper allows user to use two different pull-up voltages.
Maximum Sink Current: Per Channel: 65mA.
Per Bank (8 bits): 500mA.
Per Card: 1A.
Current Limit: Positive Temperature Coefficient circuit protector
in series with each output. Output protection resistance <18Ω.
Collector-Emitter Saturation Voltage: <0.75V @ 1mA.
<1V @ 65mA.
Logic: Negative True.
INPUT SPECIFICATIONS:
Configuration: 40 inputs with internal 10kΩ pull-up resistors pro-
vided.
Characteristics:
Input logic low voltage: 0.8V max.
Input logic high voltage: 2V min.
Input logic low current: –600µA max. @ 0V
Input logic high current: 50µA max. @ 5V
Maximum Voltage Level: 42V pk.
Logic: Positive True.
7020/7020-D General Specifications
CONNECTOR:
7020: 96-pin male DIN connector.
7020-D: Cables with 50-pin male and female D-sub connectors.
ENVIRONMENT: Operating: 0° to 50°C, up to 35°C < 80% RH. Storage:
–25° to 65°C.
7020 and 7020-D Digital I/O Interface Cards
Specifications are subject to change without notice.
Output Channel
5.3V V
R
1
R
2
R1 = Pull-up Resistor = 10kΩ
R2 = Output Protection < 18Ω
Input Channel
R
R1 = Pull-up Resistor = 10kΩ
R2 = Input Protection = 100kΩ
5V
R
1
2
EXTERNAL
Output
GND
Input
GND
Table of Contents
1 Digital I/O Configuration
1.1 Introduction......................................................................................................................................................... 1-1
1.2 Digital outputs..................................................................................................................................................... 1-1
1.3 Controlling pull-up devices................................................................................................................................. 1-1
1.4 Controlling devices using pull-up resistors......................................................................................................... 1-1
1.5 Digital inputs....................................................................................................................................................... 1-1
2 Card Connections and Installation
2.1 Introduction ........................................................................................................................................................ 2-1
2.2 Internal connections ............................................................................................................................................ 2-1
2.3 Voltage source jumpers....................................................................................................................................... 2-1
2.4 Pull-up resistors................................................................................................................................................... 2-3
2.5 Card installation .................................................................................................................................................. 2-3
2.6 Card removal....................................................................................................................................................... 2-4
2.7 Input/output connections..................................................................................................................................... 2-4
2.8 Typical connection techniques............................................................................................................................ 2-6
2.9 Typical output connection schemes .................................................................................................................... 2-7
2.10 Typical input connection scheme........................................................................................................................ 2-9
2.11 Models 7020-D and 7020-DT ............................................................................................................................. 2-9
3 Operation
3.1 Introduction ........................................................................................................................................................ 3-1
3.2 Power limits ........................................................................................................................................................ 3-1
3.3 Channel status display......................................................................................................................................... 3-1
3.4 Channel assignments........................................................................................................................................... 3-2
3.5 Controlling output channels ................................................................................................................................ 3-3
3.6 Turning output channels On and Off .................................................................................................................. 3-3
3.7 Scanning output channels.................................................................................................................................... 3-4
3.8 Reading input channels ....................................................................................................................................... 3-4
3.9 IEEE-488 bus operation ...................................................................................................................................... 3-4
3.10 Turning output channels On and Off .................................................................................................................. 3-4
3.11 Scanning output channels.................................................................................................................................... 3-5
3.12 Reading input channels ....................................................................................................................................... 3-5
i
4 Service Information
4.1 Introduction ........................................................................................................................................................ 4-1
4.2 Handling and cleaning ........................................................................................................................................ 4-1
4.3 Channel functionality test ................................................................................................................................... 4-1
4.4 Static-sensitive devices....................................................................................................................................... 4-2
4.5 Principles of operation........................................................................................................................................ 4-2
4.6 Block diagram..................................................................................................................................................... 4-2
4.7 ID data circuits.................................................................................................................................................... 4-2
4.8 Output channel control ....................................................................................................................................... 4-3
4.9 Input channel control .......................................................................................................................................... 4-4
4.10 Power-on safeguard ............................................................................................................................................ 4-4
4.11 Troubleshooting.................................................................................................................................................. 4-4
4.12 Troubleshooting access....................................................................................................................................... 4-4
4.13 Troubleshooting procedure................................................................................................................................. 4-4
5 Replaceable Parts
5.1 Introduction......................................................................................................................................................... 5-1
5.2 Parts lists............................................................................................................................................................. 5-1
5.3 Ordering information .......................................................................................................................................... 5-1
5.4 Factory service.................................................................................................................................................... 5-1
5.5 Component layouts and schematic diagrams...................................................................................................... 5-1
ii
List of Illustrations
1 Digital I/O Configuration
Figure 1-1 Output configurations for pull-up devices ................................................................................................. 1-2
Figure 1-2 Output configuration using pull-up resistance ............................................................................................ 1-2
Figure 1-3 Input configuration...................................................................................................................................... 1-2
2 Card Connections and Installation
Figure 2-1 Voltage source jumpers for output channels............................................................................................... 2-2
Figure 2-2 Component locations — scanner board ...................................................................................................... 2-2
Figure 2-3 Voltage source jumper installation ............................................................................................................. 2-3
Figure 2-4 Model 7020 card installation in Model 7001 .............................................................................................. 2-4
Figure 2-5 96-pin DIN connector pinout ...................................................................................................................... 2-5
Figure 2-6 Typical round cable connection techniques ................................................................................................ 2-6
Figure 2-7 Model 7011-KIT-R (with/cable) assembly ................................................................................................. 2-7
Figure 2-8 Model 7011-MTR connector pinout ........................................................................................................... 2-7
Figure 2-9 Digital output, solenoid control .................................................................................................................. 2-8
Figure 2-10 Digital output, relay control........................................................................................................................ 2-8
Figure 2-11 Digital output, motor control ...................................................................................................................... 2-8
Figure 2-12 Digital output, logic device control............................................................................................................. 2-8
Figure 2-13 Digital input, monitoring micro-switches ................................................................................................... 2-9
Figure 2-14 Mating the PC-boards ................................................................................................................................. 2-9
Figure 2-15 Mating connector (solder-side view) ........................................................................................................ 2-10
3 Operation
Figure 3-1 Model 7001 channel status display ............................................................................................................. 3-2
Figure 3-2 Model 7002 channel status display (slot 1)................................................................................................. 3-2
Figure 3-3 Display organization for input and output channels ................................................................................... 3-2
Figure 3-4 Model 7020 programming channel assignments ........................................................................................ 3-3
4 Service Information
Figure 4-1 Testing an input or output channel.............................................................................................................. 4-2
Figure 4-2 Model 7020 block diagram ......................................................................................................................... 4-2
Figure 4-3 Start and stop sequences ............................................................................................................................. 4-3
Figure 4-4 Transmit and acknowledge sequence.......................................................................................................... 4-3
iii
iv
List of Tables
2 Card Connections and Installation
Table 2-1 Pull-up resistors identification .................................................................................................................... 2-3
Table 2-2 Output channel terminal identification ....................................................................................................... 2-5
Table 2-3 Input channel terminal identification .......................................................................................................... 2-5
Table 2-4 Miscellaneous terminal identification......................................................................................................... 2-6
Table 2-5 I/O connection accessories.......................................................................................................................... 2-6
Table 2-6 Terminal identification.............................................................................................................................. 2-10
4 Service Information
Table 4-1 Recommended troubleshooting equipment................................................................................................. 4-4
Table 4-2 Troubleshooting procedure ......................................................................................................................... 4-5
5 Replaceable Parts
Table 5-1 Model 7020 mass terminal board, parts list ................................................................................................ 5-2
Table 5-2 Model 7020 scanner board, parts list .......................................................................................................... 5-2
v
vi
1
Digital I/O Configuration
1.1 Introduction
This section covers the basic digital input and output configurations for the Model 7020. Connection information for
these configurations is provided in Section 2 of this manual,
while operation (front panel and IEEE-488 bus) is explained
in Section 3.
1.2 Digital outputs
Output channels use negative true logic. That is, the output is
pulled low when the channel is turned on (closed).
Conversely, the output goes high when the channel is turned
off (open).
1.3 Controlling pull-up devices
Typically, the digital outputs are used to provide drive for
relatively high current devices such as solenoids, relays and
small motors. The configurations for these applications are
shown in Figure 1-1. Figure 1-1A uses the internal voltage
source (5.3V), while Figure 1-1B allows you to use an
external voltage source (V) for devices that require a higher
voltage (25V maximum). Internal jumpers are used to select
the voltage source. At the factory, the internal 5.3V source is
selected.
As shown in Figure 1-1, each output channel has a resettable
fuse (F) that is used to protect the output driver from excessive current. During normal operation, the resettable fuse is
in a low resistance state like a regular fuse. When output current reaches the trip level (around 180mA at 23°C, 130mA at
50°C), the fuse goes to a high resistance state that interrupts
the damaging high current. The fuse will automatically reset
to the low resistance state when the fault condition is removed.
Each output channel uses a fly-back diode for protection
when switching an inductive device, such as a solenoid coil.
This diode diverts the potentially damaging fly-back voltage
away from the driver.
1.4 Controlling devices using pull-up resistors
When interfacing outputs to high-impedance devices (i.e.
logic devices), pull-up resistors are used to achieve the appropriate logic level. Figure 1-2 shows the output configuration using the 10k Ω pull-up resistor (R
The configuration in Figure 1-2 uses the internal 5.3V source
as the high logic level. Notice that the 5.3V source is also
used to power the device. If you need a higher logic level,
you can place the jumper in the alternate position and apply
an external voltage (via V
EXT1
or V
EXT2
).
P
).
1.5 Digital inputs
Input channels use positive true logic. A channel is on
(closed) when the input is high (up to 42V peak). Conversely,
a channel is off (open) when the input is pulled low. As
shown in Figure 1-3, each channel uses a 10k Ω pull-up resistor (R
) that is connected to 5V. Thus, with nothing connect-
1
ed to the channel, the input is pulled high to 5V which turns
the channel on (closed).
The digital input is compatible with external TTL logic.
Each built-in pull-up resistor provides level shifting so that
devices such as micro-switches can be monitored. Each input
has a protection network that clamps the input at 5.7V. This
allows logic levels up to 42V peak to be monitored.
1-1
Digital I/O Configuration
7020
JUMPER
5.3V
F
DRIVER
A. Using Internal Voltage Source (5.3V)
7020
JUMPER
F
DRIVER
<18Ω
<18Ω
V
INT
OUTPUT
V
INT
OUTPUT
SOLENOID
OR RELAY
V
SOLENOID
OR RELAY
COIL
COIL
7020
Figure 1-3
Input configuration
R
2
100kΩ
R
10kΩ
1
INPUT
GND
R1 = Pull-up resistor
R
= Input protection resistor
2
B. Using External Voltage Source (25V maximum)
Figure 1-1
Output configurations for pull-up devices
7020
JUMPER
5.3V
DRIVER
Note: Pull-up resistor (R
Figure 1-2
Output configuration using pull-up resistance
) installed
P
R
10kΩ
V
INT
P
OUTPUT
<18Ω
F
GND
A
OR
B
GATE
LOGIC
DEVICE
Y
1-2
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