Tektronix VX4780 User Manual
User Manual
VX4780
16-Channel Signal Conditioner
070-9488-00
This document supports firmware version 1.00
and above.
Warning
The servicing instructions are for use by qualified
personnel only. To avoid personal injury, do not
perform any servicing unless you are qualified to
do so. Refer to the Safety Summary prior to
performing service.
Copyright T ektronix, Inc. 1995. All rights reserved. Licensed software products are owned by Tektronix or its suppliers
and are protected by United States copyright laws and international treaty provisions.
Use, duplication, or disclosure by the Government is subject to restrictions as set forth in subparagraph (c)(1)(ii) of the
Rights in T echnical Data and Computer Software clause at DFARS 252.227-7013, or subparagraphs (c)(1) and (2) of the
Commercial Computer Software – Restricted Rights clause at F AR 52.227-19, as applicable.
T ektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes
that in all previously published material. Specifications and price change privileges reserved.
Printed in the U.S.A.
T ektronix, Inc., P.O. Box 1000, Wilsonville, OR 97070–1000
TEKTRONIX and TEK are registered trademarks of T ektronix, Inc.
VXIbus is a trademark of the VXI Consortium.
SurePath and Intelliframe are registered trademarks of T ektronix, Inc.
WARRANTY
T ektronix warrants that this product will be free from defects in materials and workmanship for a period of three (3) years
from the date of shipment. If any such product proves defective during this warranty period, T ektronix, at its option, either
will repair the defective product without charge for parts and labor, or will provide a replacement in exchange for the
defective product.
In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of the
warranty period and make suitable arrangements for the performance of service. Customer shall be responsible for
packaging and shipping the defective product to the service center designated by T ektronix, with shipping charges prepaid.
T ektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the
T ektronix service center is located. Customer shall be responsible for paying all shipping charges, duties, taxes, and any
other charges for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate
maintenance and care. T ektronix shall not be obligated to furnish service under this warranty a) to repair damage resulting
from attempts by personnel other than T ektronix representatives to install, repair or service the product; b) to repair
damage resulting from improper use or connection to incompatible equipment; or c) to service a product that has been
modified or integrated with other products when the effect of such modification or integration increases the time or
difficulty of servicing the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THIS PRODUCT IN LIEU OF ANY
OTHER WARRANTIES, EXPRESSED OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY
IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
TEKTRONIX’ RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND
EXCLUSIVE REMEDY PROVIDED TO THE CUST OMER FOR BREACH OF THIS WARRANTY. TEKTRONIX
AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT , SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS
ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.
Table of Contents
Getting Started
Operating Basics
Syntax and Commands
General Safety Summary iii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preface vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Product Description 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessories 1–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Controls and Indicators 1–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration 1–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 1–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation Checklist 1–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Check 1–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Overview 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-On 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Instrument I/O: VXIbus Basics 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Command Syntax 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Command Groups 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Commands 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Module Commands 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Command Descriptions 3–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IEEE-488.2 Common Commands 3–33. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status and Events
Status and Event Reporting System 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Byte Register 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Request Enable Register 4–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standard Event Status Register 4–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Event Status Enable Register 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Output Queue 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The System Error and Event Queue 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status and Event Reporting Process 4–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Messages 4–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendices
Appendix A: Specifications A–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix B: Input/Output Connections B–1. . . . . . . . . . . . . . . . . . . . . . . .
Appendix C: Examples C–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix D: Diagnostics D–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VX4780 16-Channel Signal Conditioner User Manual
i
Contents
Appendix E: User Service E–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix F: Replaceable Parts F–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ii
VX4780 16-Channel Signal Conditioner User Manual
General Safety Summary
Review the following safety precautions to avoid injury and prevent damage to
this product or any products connected to it.
Only qualified personnel should perform service procedures.
While using this product, you may need to access other parts of the system. Read
the General Safety Summary in other system manuals for warnings and cautions
related to operating the system.
Injury Precautions
Product Damage
Precautions
Avoid Electric Overload. To avoid electric shock or fire hazard, do not apply a
voltage to a terminal that is outside the range specified for that terminal.
Avoid Electric Shock. To avoid injury or loss of life, do not connect or disconnect
probes or test leads while they are connected to a voltage source.
Ground the Product. This product is indirectly grounded through the grounding
conductor of the mainframe power cord. To avoid electric shock, the grounding
conductor must be connected to earth ground. Before making connections to the
input or output terminals of the product, ensure that the product is properly
grounded.
Do Not Operate Without Covers. To avoid electric shock or fire hazard, do not
operate this product with covers or panels removed.
Use Proper Fuse. To avoid fire hazard, use only the fuse type and rating specified
for this product.
Do Not Operate in Wet/Damp Conditions. To avoid electric shock, do not operate
this product in wet or damp conditions.
Do Not Operate in an Explosive Atmosphere. To avoid injury or fire hazard, do not
operate this product in an explosive atmosphere.
Provide Proper Ventilation. To prevent product overheating, provide proper
ventilation.
Do Not Operate With Suspected Failures. If you suspect there is damage to this
product, have it inspected by qualified service personnel.
Symbols and Terms
VX4780 16-Channel Signal Conditioner User Manual
T erms in this Manual. These terms may appear in this manual:
WARNING. Warning statements identify conditions or practices that could result
in injury or loss of life.
iii
General Safety Summary
CAUTION. Caution statements identify conditions or practices that could result in
damage to this product or other property.
T erms on the Product. These terms may appear on the product:
DANGER indicates an injury hazard immediately accessible as you read the
marking.
WARNING indicates an injury hazard not immediately accessible as you read the
marking.
CAUTION indicates a hazard to property including the product.
Symbols on the Product. The following symbols may appear on the product:
Certifications and
Compliances
DANGER
High Voltage
Protective Ground
(Earth) T erminal
ATTENTION
Refer to Manual
Double
Insulated
Refer to the specifications section for a listing of certifications and compliances
that apply to this product.
iv
VX4780 16-Channel Signal Conditioner User Manual
Service Safety Summary
Only qualified personnel should perform service procedures. Read this Service
Safety Summary and the General Safety Summary before performing any service
procedures.
Do Not Service Alone. Do not perform internal service or adjustments of this
product unless another person capable of rendering first aid and resuscitation is
present.
Disconnect Power. To avoid electric shock, disconnect the main power by means
of the power cord or, if provided, the power switch.
Use Care When Servicing With Power On. Dangerous voltages or currents may
exist in this product. Disconnect power, remove battery (if applicable), and
disconnect test leads before removing protective panels, soldering, or replacing
components.
VX4780 16-Channel Signal Conditioner User Manual
v
Preface
Conventions
This manual assumes you are familiar with VXIbus instruments and operation
and with the purpose and function of this instrument.
Please read and follow all instructions for installation and configuration. Use the
Installation Checklist to ensure proper installation and to record your initial
settings.
The Operating Basics section gives a summary of VXIbus operation and
presents an overview of the operation of this instrument.
The Syntax and Commands section provides a summary of all the commands
followed by detailed descriptions of each command.
The Status and Events section contains an explanation of the Status and Event
Reporting System and lists the system messages. Appendix C: Examples contains
example programs that demonstrate the programmable features of this instrument.
The names of all switches, controls, and indicators appear in this manual exactly
as they appear on the instrument.
Specific conventions for programming are given in the sections Syntax and
Commands and Appendix C: Examples.
VX4780 16-Channel Signal Conditioner User Manual
vii
Getting Started
Product Description
This section begins with a brief description of the VX4780 16-Channel Signal
Conditioner, and explains how to configure and install the module in a VXIbus
mainframe. The quick functional check, also included in this section, assures that
the instrument operates properly.
The VX4780 16-Channel Signal Conditioner is a printed circuit board assembly
for use in a mainframe conforming to the VXIbus Specification. Figure 1–1
shows a functional block diagram of the VX4780. The VX4780 is a single slot,
C-size VXI module with the following features:
Input Characteristics
H Differential inputs
H Input isolation relays
H 2 M Differential input impedance
H Command selectable input attenuation of 10 and 100 V/V.
H Command selectable input attenuator bypass
H Command selectable gain of 1, 2, 5, 10, 20, 50 and 100 V/V.
H Command selectable AC or DC input coupling
H 250 V overvoltage protection
Low Pass Filtering
H 4 Pole Bessel Response
H Command selectable cutoff frequencies from 468 Hz to 107 kHz
Output Characteristics
H Differential outputs
H Output isolation relays
H 50 output impedance
H ±10 V output voltage
VX4780 16-Channel Signal Conditioner User Manual
1–1
Getting Started
CHANNEL 1 – 8
INPUT CONNECTOR
POSITIVE
INPUT
NEGATIVE
INPUT
CHANNEL 1 of 16
/10
ATTENUATOR
/100
/10
ATTENUATOR
/100
OVER
VOLTAGE
PROTECTION
OVER
VOLTAGE
PROTECTION
VARIABLE GAIN
DIFFERENTIAL
AMPLIFIER
GAIN
TRIM
DAC
CHANNEL 9 – 16
INPUT CONNECTOR
POSITIVE
INPUT
NEGATIVE
INPUT
SELFTEST
VARIABLE
VOLTAGE
SOURCE
CHANNEL 16 of 16
/10
ATTENUATOR
/100
/10
ATTENUATOR
/100
OVER
VOLTAGE
PROTECTION
OVER
VOLTAGE
PROTECTION
VARIABLE GAIN
DIFFERENTIAL
AMPLIFIER
GAIN
TRIM
DAC
Figure 1–1: VX4780 Functional Block Diagram
1–2
VX4780 16-Channel Signal Conditioner User Manual
OFFSET
TRIM
DAC
TUNABLE
LOWPASS
FILTER
DIFFERENTIAL
OUTPUT
AMPLIFIER
Getting Started
CHANNEL 1 – 8
OUTPUT CONNECTOR
POSITIVE
OUTPUT
NEGATIVE
OUTPUT
OFFSET
TRIM
DAC
TUNABLE
LOWPASS
FILTER
DIFFERENTIAL
OUTPUT
AMPLIFIER
CHANNEL 9 – 16
OUTPUT CONNECTOR
POSITIVE
OUTPUT
NEGATIVE
OUTPUT
SELFTEST
OUTPUT
MUX
CHANNEL 1
INPUT
OUTPUT
CHANNEL 16
INPUT
SELFTEST
VOLTAGE
SOURCE
INPUT
SELFTEST
A/D CONVERTER
Figure 1–1: VX4780 Functional Block Diagram (cont.)
VX4780 16-Channel Signal Conditioner User Manual
1–3
Getting Started
H DC coupled
H Short circuit protected
Additional Features
H Extensive self test/diagnostics
H SCPI 1994 / IEEE-488.2 compatible command set
H Command selectable DC offset trim and gain trim for system level calibra-
tion
The VX4780 VXI Interface includes the following features:
H CPU:
Zilog Z88C00 microcontroller with 20 MHz clock
64 Kbyte of EPROM and 32 Kbyte of RAM
H VXI Interface:
Fuses
VXI Rev 1.4 message based device
Supports Fast Handshake word serial protocol data transfers
IEEE-488.2 device
Logical address selectable with two rotary hexadecimal switches
Interrupter level selectable with a rotary hexadecimal switch. Selects one
of seven levels or disables interrupt generation
The VX4780 has three 2 amp fast-acting fuses: one for +5 V power (F1181), one
for +24 V power (F1481), and one for –24 V power (F1581).
If the +5 V fuse opens, the VXIbus Resource Manager will be unable to assert
SYSFAIL INHIBIT to disable SYSFAIL*.
If a +5 V fuse opens, remove the fault before replacing the fuse. Replacement
fuse information is given in the Appendix F:Replaceable Parts List.
1–4
VX4780 16-Channel Signal Conditioner User Manual
Getting Started
LEDs
BITE (Built-in Test
Equipment)
The following LEDs are visible at the top of the VX4780 Module front panel to
indicate the status of the module operation.
LED When lighted, indicates
Power power is applied to the module
Failed the module is in the FAILED state
Message the VX4780 is communicating with its commander on the VXI bus
Error the VX4780 has detected a syntax error in a command sent by its
commander or has detected a parameter in a command that is out of range
or has failed self test. When one of these conditions is detected, the Error
LED is lighted and an error message describing the error is placed in the
module Error/Event queue. The Error LED remains lighted until the entire
Error/Event queue is read. Use the SYSTem:ERRor? query to access the
Error/Event queue.
Built-in Test Equipment (BITE) is provided by extensive self tests that are
automatically invoked on power-on and can also be invoked on command.
An abbreviated self test is performed at power-on. At power-on, only the CPU
and RAM are tested. When self test is initiated with the *TST? query, the tests
listed below are performed. Self test can test all channels or selected channels.
Pass/Fail messages that indicate the results of the self test are placed in the
Error/Event queue. These messages can be read with the SYStem:ERRor? query.
Test Performs
NOVRAM Checksum The checksums of gain and offset calibration constants stored
in NOVRAM are calculated and checked against the stored
checksums. A gain constant checksum and an offset constant
checksum are stored for each channel.
Offset calibration circuitry The DC offset trim DAC and associated circuitry is tested.
Test source The self test variable voltage source is tested.
Input attenuator The performance of the input attenuator is verified at
attenuation settings of /10 and /100 and with the attenuator
bypassed. This test is performed with nominal attenuation
calibration factors, then repeated with stored calibration
factors.
Gain calibration circuitry The gain trim DAC and associated circuitry is tested.
Lowpass filter The cutoff frequency of the lowpass filter is checked at cutoff
frequencies of 468 Hz, 936 Hz, 1872 Hz, 3744 Hz, and
7133 Hz. This test verifies that the cutoff frequency tuning
circuitry is functioning properly.
VX4780 16-Channel Signal Conditioner User Manual
1–5
Getting Started
Accessories
Test Performs
AC coupling capacitors The positive input and negative input AC coupling capacitors
are checked.
Variable gain amplifiers The variable gain amplifier is checked at gains of 1, 2, 5, 10,
20, 50, and 100 V/V . This test is performed with nominal gain
calibration factors, then repeated with stored calibration
factors.
Table 1–1 lists the standard accessories included with the VX4780.
T able 1–1: Standard Accessories
Accessory Part Number
VX4780 User Manual 070-9488-XX
VX4780 Reference 070-9489-XX
Controls and Indicators
Switches
Table 1–2 lists the options available for the VX4780.
T able 1–2: Options
Option Part Number
Input Cable Channels 1
through 8
Input Cable Channels 9
through 16
Output Cable VX4780 to
VX4244
174-3543-00
174-3553-00
174-3542-00
The following controls are provided to select the functions of the VX4780
operating environment. Figures 1–2 and 1–3 illustrate the physical location of
these controls and indicators.
The Logical Address switches, VMEbus Interrupt Level Select switch, and Halt
switch must be correctly set to insure proper operation. See Configuration for
details on how to set the switches.
1–6
VX4780 16-Channel Signal Conditioner User Manual
Switches as viewed
from the rear of instrument
(labels are on the back shield)
Getting Started
LOGICAL
ADDRS
LO
HI
INTRPT
S1481
F1181
F1481
F1581
Figure 1–2: VX4780 Connectors, Indicators, and Switch Locations
Figure 1–3: VX4780 Front Panel
VX4780 16-Channel Signal Conditioner User Manual
1–7
Getting Started
Configuration
The following switches must be correctly set to ensure proper operation. Refer to
Figure 1–2 for their physical locations.
Logical Address Switches
IEEE-488 Address
Each functional module in a VXIbus System must be assigned a unique logical
address, from 1 to decimal 255 (hexadecimal FF). The base VMEbus address of
the VX4780 is set to a value between 1 and hexadecimal FF (FF
) by two
16
hexadecimal rotary switches. Align the desired switch position with the arrow on
the module shield.
The physical address of the instrument is on a 64 byte boundary. If the Logical
Address switch representing the most significant digit (LA-HI) of the logical
address is set to position X and the switch representing the least significant digit
(LA-LO) of the logical address is set to position Y, then the base physical
address of the VX4780 will be [(40
L.A. HI LO decimal hexadecimal
A
16
15
LA. is the Logical Address
0
16
1
16
16
A
16
5
16
(64 * 10) + 49152 = 49792 (4016 * A16) + C00016 = C280
(64 * 21) + 49152 = 50496 (4016 * 1516) + C00016 = C540
× XY16) + C00016]. For example:
16
Base Physical Address
16
16
In order to use and program the VX4780 Signal Conditioner in an IEEE-488
environment you must know the IEEE-488 address of the module. Different
manufacturers of IEEE-488 interface devices might have different algorithms for
equating a logical address with an IEEE-488 address. Consult the operating
manual of the IEEE-488 Interface Module being used.
VMEbus Interrupt Level
Select Switch
1–8
Each function module in a VXIbus System can generate an interrupt at a
specified level on the VMEbus to request service from the interrupt handler
located on its commander. Set the interrupt level to the same level as the
interrupt handler on that commander. The VMEbus interrupt level on which the
VX4780 Signal Conditioner generates interrupts is set by a rotary switch. Align
the desired switch position with the arrow on the module shield.
Valid VMEbus Interrupt Level Select switch settings are one through seven, with
setting one equivalent to level one, and so on. The level chosen should be the
same as the level set on the VX4780 interrupt handler, typically the module
commander. Setting the switch to zero or eight will disable the module interrupts. Do not use switch settings nine through f.
VX4780 16-Channel Signal Conditioner User Manual
Getting Started
Interrupts are used by the module to return VXIbus Protocol Events to the
module commander. Refer to the Operating Basics section for more information
on interrupts. The VXIbus Protocol Events supported by the module are listed in
Appendix A: Specifications.
Halt Switch
Installation
Tools Required
Requirements and Notes
Switch S1481 contains four rockers. Rocker number 1 serves as a Halt Switch.
The setting of this switch selects the response of the VX4780 Module when the
Reset bit in the module VXIbus Control register is set. If the Halt switch is in the
closed position, the VX4780 is reset to its power-on state and all programmed
module parameters are set to their default values. If the Halt switch is set to the
open position, the module will ignore the Reset bit and no action will take place.
Rockers 2 through 4 on switch S1481 are reserved for future use and should be
placed in the closed position.
Note that the module is not in strict compliance with the VXIbus Specification
when the Halt switch is in the open position.
This section describes how to install the VX4780.
A slotted screwdriver set is required for proper installation.
The VX4780 Signal Conditioner is a C-size VXIbus instrument module and
therefore may be installed in any C- or D-size VXIbus mainframe slot other than
slot 0. To install the module in a D-size mainframe, consult the operating manual
for the mainframe. Refer to Configuration for information on selecting and
setting the Logical Address switch of the module. This switch defines the
programming address of your module. To avoid confusion, it is recommended
that the slot number and the logical address be the same.
NOTE. Note that there are two printed ejector handles on the card. To avoid
installing the card incorrectly, make sure the ejector marked “VX4780” is at the
top.
Verify that the mainframe is able to provide adequate cooling and power with
this module installed. Refer to the mainframe Operating Manual for instructions.
VX4780 16-Channel Signal Conditioner User Manual
1–9
Getting Started
If the VX4780 is used in a Tektronix mainframe, all VX4780 cooling requirements are met.
NOTE. If the VX4780 is inserted in a slot with any empty slots to the left of the
module, the VME daisy-chain jumpers must be installed on the backplane in
order for the VXI Module to operate properly. Check the manual of the mainframe being used for jumpering instructions. Jumpers are not necessary for
autoconfiguring backplane designs.
Installation Procedure
Follow these steps to install the VX4780.
CAUTION. The VX4780 Signal Conditioner is a piece of electronic equipment and
therefore has some susceptibility to electrostatic damage (ESD).To avoid (ESD),
use precautions when handling the module.
1. Record the revision level, serial number (located on the label on the shield of
the VX4780), and switch settings on the Installation Checklist.
2. Verify that the switches are set to the correct values. Refer to Configuration
for more information on setting switches.
3. Make sure that the mainframe power is off.
4. Insert the module into one of the instrument slots of the mainframe (see
Figure 1–4).
5. Cable Installation: Use the correct cable to interface between the module I/O
connector and the Unit Under Test (UUT). The recommended cable is listed
in Appendix F: Replaceable Parts List.
1–10
VX4780 16-Channel Signal Conditioner User Manual
Figure 1–4: Module Installation
Getting Started
VX4780 16-Channel Signal Conditioner User Manual
1–11
Getting Started
Installation Checklist
Installation parameters will vary depending on the mainframe being used. Be
sure to consult the mainframe operating manual before installing and operating
the module.
Revision Level:
Serial No.:
Mainframe Slot Number:
Switch Settings:
VXIbus Logical Address Switch:
Interrupt Level Select Switch:
Halt Switch:
Cable Installed (if any):
1–12
Performed by: _______________________ Date: _____________
VX4780 16-Channel Signal Conditioner User Manual
Functional Check
Getting Started
In addition to the self tests, you can also perform an operational check of the
VX4780.
Self Test
The VX4780 16-Channel Signal Conditioner executes a self test at power-on, on
direction of a VXIbus hard or soft reset condition or on command. The power-on
self test consists of an interface self test. The self test requested by command
performs an instrument self test. A VXIbus hard reset occurs when another
device, such as the VXIbus Resource Manager, asserts the backplane line
SYSRESET*. A VXIbus soft reset occurs when another device, such as the
VX4780 commander, sets the Reset bit in the VX4780 Control register.
During power-on, or a hard or soft reset, the following actions take place:
1. The SYSFAIL* (VME system-failure) line is set active, indicating that the
module is executing a self test, and the Failed LED is lighted. For a soft
reset, SYSFAIL* is set. All Tektronix commanders will simultaneously set
SYSFAIL INHIBIT to prevent the resource manager from prematurely
reporting the failure of a card.
2. On completion of the interface self test, SYSFAIL* is deasserted. If the test
fails, the SYSFAIL* line remains active. If the interface self test passed, the
SYSFAIL* line is released, and the module enters the VXIbus PASSED state
(ready for normal operation). If it failed, the module enters the VXIbus
FAILED state.
The default condition of the VX4780 after the completion of the power-on self
test is as follows:
Input Isolation Relays: Open
Input Coupling: AC
Input Attenuator Setting: /10
Input Attenuator State: Inserted
Gain: 1 V/V
Lowpass Filter Cutoff Frequency: 468 Hz
Output Isolation Relays: Open
You can run the self test at any time during normal operation by using the *TST?
command. At the end of a self test initiated by this command, the module is
restored to its pretest state.
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Getting Started
During a commanded self test:
1. SYSFAIL* is not asserted.
2. All settings of all channels are restored to their pretest state.
Operational
Check
Send a *CLS command to the VX4780 to clear the Error/Event queue. Send a
*TST? query to the VX4780 to initiate a self test of all channels. Wait one
minute, then read the module response. A response of 0 indicates that all
channels passed passed self test. A response of 1 indicates that one or more
channels failed self test. Read the results of self test from the Error/Event queue
by sending SYSTem:ERRor? queries and reading the module response until the
Error queue is empty.
Set all channels to the configuration listed below by sending the listed commands:
Configuration Command
Input Isolation Relays: Open input:state off,(@1:16)
Input Coupling: DC input:coupling dc,(@1:16)
Input Attenuator Setting: /10 input:att 10,(@1:16)
Input Attenuator State: Inserted input:att:State on,(@1:16)
Gain: 10 input:gain 10,(@1:16)
Lowpass Filter Cutoff Frequency: 20 kHz input:filter:lpass:Freq 20e3,(@1:16)
Output Isolation Relays: Closed output:state on,(@1:16)
1–14
Note that the overall channel gain for all channels is set to 1 (channel gain /
channel attenuation = 10/10 = 1). Also note that the self test voltage source is
applied to the input of all channels that have their input isolation relays set to the
open position. Apply a 5 V
1 kHz square wave to all channel inputs by
p-p
sending the command:
Use a 2-channel oscilloscope to observe a 5 V
1 kHz square wave at each of
p-p
the channel outputs. Connect one channel of the oscilloscope to a VX4780
channel positive output. Connect the other oscilloscope channel to the VX4780
channel negative output. Display the difference of the oscilloscope channel
inputs. Send a VXI Clear command to the VX4780 to halt the square wave
generation and to allow additional commands to be sent to the VX4780.
VX4780 16-Channel Signal Conditioner User Manual
Close all input isolation relays by sending the command:
input:state on,(@1:16)
Getting Started
SYSFAIL* Operation
Use a function generator to apply a 20 V
inputs. Observe a 20 V
1 kHz sine waveform at all channel outputs. Set the
p-p
1 kHz sine waveform to all channel
p-p
frequency of the function generator waveform to 20 kHz (the current cutoff
frequency of the lowpass filter). Note that the amplitude at all channel outputs
has dropped to .7071 * 20 V
= 14 V
p-p
This verifies that the lowpass filters
p-p.
are functioning properly.
SYSFAIL* becomes active during power-on, hard or soft reset, or self test, or if
the module loses any of its power voltages. When the mainframe Resource
Manager detects SYSFAIL* set, it will attempt to inhibit the line. This causes
the VX4780 16-Channel Signal Conditioner to deactivate SYSFAIL* except
when +5 V power is lost.
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Operating Basics
Functional Overview
The VX4780 16-Channel Signal Conditioner is a VXIbus message-based
instrument and communicates using the VXIbus Word Serial Protocol. The
module is programmed by issuing ASCII characters from the system controller
to the VX4780 via the module VXIbus commander and the VXIbus mainframe
backplane. Refer to the manual for the VXIbus device that will be the VX4780
Signal Conditioner commander for details on the operation of that device.
If the module commander is a Tektronix IEEE-488 Interface Module, refer to the
operating manual for the module and Appendix C: Examples in this manual for
information on how the system controller communicates with the commander
being used.
The VX4780 contains sixteen signal conditioning channels. The high channel
input impedance minimizes the loading of signal sources that are connected to
the module inputs. Under program control, the input signal can be AC or DC
coupled to the channel input. The overall channel gain (channel gain divided by
channel attenuation) can be programmed in 1/2/5 steps from 0.01 V/V to
100 V/V. This capability enables the VX4780 to scale a wide range of input
voltages to a normalized output voltage of
±10 V.
A differential input configuration enables the VX4780 to reject common mode
interference that may be coupled onto the input signal from nearby sources of
EMI. Overvoltage protection circuitry that follows the input attenuator protects
the channel’s input circuitry from voltages of up to 250 V.
After the input signal is scaled by the input attenuator and variable gain
amplifier, it is lowpass filtered. This filter serves as an antialiasing filter for a
digitizer (typically a VX4244 16-Channel Digitizer) connected to the channel
output. The cutoff frequency of the low pass filter is command programmable
over the frequency range of 468 Hz to 107 kHz. The filter cutoff frequency is
typically programmed to a value less than or equal to one half of the sampling
frequency of the digitizer. The lowpass filter is designed to have a Bessel
response. The linear phase response of this type of filter preserves the phase
relationship of the frequency components of the input signal. This gives the
VX4780 an excellent pulse response.
Each channel contains input and output isolation relays which are used to
connect or disconnect the VX4780 from external devices under program control.
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Operating Basics
Power-On
The instrument runs its self test and is ready for programming five seconds after
power-on. The VXIbus Resource Manager can add an additional delay. The
default condition of the module after power-on is listed in the *RST command
description. Self-test failures are described in the SYSTem:ERRor command
description.
At power-on, the front panel LEDs will be in the following states:
Power LED On
Failed LED Off
Error LED Off
Message LED On when the module is addressed by its com-
mander, otherwise this LED is off.
The format and syntax for the command strings are described in the Command
Syntax section. A complete description of each command in alphabetical order is
in the Command Descriptions section.
Instrument I/O: VXIbus Basics
NOTE. If the user’s mainframe has other manufacturers’ computer boards
operating in the role of VXIbus foreign devices, the assertion of BERR* (as
defined by the VXIbus Specification) may cause operating problems on these
boards.
The VX4780 Module installed on a switching module is a C-size single slot
VXIbus Message-Based Word Serial instrument. It uses the A16, D16 VME
interface available on the backplane P1 connector and does not require any A24
or A32 address space. The module is a D16 interrupter.
The VX4780 is neither a VXIbus commander nor a VMEbus master; therefore it
does not have a VXIbus Signal register. The VX4780 is a VXIbus messagebased servant.
The module supports the Normal Transfer Mode of the VXIbus using the Write
Ready, Read Ready, Data In Ready (DIR), and Data Out Ready (DOR) bits of
the module Response register.
A Normal Transfer Mode read of the VX4780 proceeds as follows:
1. The commander reads the VX4780 Response register and checks if the Write
Ready and DOR bits are true. If they are, the commander proceeds to the
2–2
VX4780 16-Channel Signal Conditioner User Manual
Operating Basics
next step. If not, the commander continues to poll these bits until they
become true.
2. The commander writes the Byte Request command (hexadecimal 0DEFF) to
the Data Low register of the VX4780.
3. The commander reads the VX4780 Response register and checks if the Read
Ready and DOR bits are true. If they are, the commander proceeds to the
next step. If not, the commander continues to poll these bits until they
become true.
4. The commander reads the VX4780 Data Low register.
A Normal Transfer Mode write to the VX4780 proceeds as follows:
1. The commander reads the VX4780 Response register and checks if the Write
Ready and DIR bits are true. If they are, the commander proceeds to the next
step. If not, the commander continues to poll the Write Ready and DIR bits
until they are true.
2. The commander writes the Byte Available command which contains the data
(hexadecimal 0BCXX or 0BDXX, depending on the End bit) to the Data
Low register of the VX4780.
The module also supports the Fast Handshake Mode during readback. In this
mode, the module is capable of transferring data at optimal backplane speed
without needing the commander to test any of the handshake bits. The VX4780
asserts BERR* to switch from Fast Handshake Mode to Normal Transfer Mode,
per VXI Specification. The VX4780 Read Ready, Write Ready, DIR and DOR
bits react properly, in case the commander does not support the Fast Handshake
Mode.
A Fast Handshake Transfer Mode read of the VX4780 proceeds as follows:
1. The commander writes the Byte Request command (hexadecimal 0DEFF) to
the VX4780 Data Low register.
2. The commander reads the VX4780 Data Low register.
A Fast Handshake Transfer Mode write of the VX4780 proceeds as follows:
The commander writes the Byte Available command which contains the data
(hexadecimal 0BCXX or 0BDXX, depending on the End bit) to the Data
Low register of the VX4780. The commander may immediately write
another Byte Available command without having to check the Response
register.
The module has no registers beyond those defined for VXIbus message based
devices. All communications with the module are through the Data Low register,
the Response register, or the VXIbus interrupt cycle. Any attempt by another
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Operating Basics
module to read or write to any undefined location of the VX4780 address space
may cause incorrect operation of the module.
As with all VXIbus devices, the VX4780 has registers located within a 64 byte
block in the A16 address space. The base address of the VX4780 device registers
is determined by the device unique logical address and can be calculated as
follows:
Configuration Registers
Base Address = V
* 4016 + C000
16
16
where V is the device logical address as set by the Logical Address switches.
Table 2–1 contains a list of the Configuration registers and a complete description of each register. The offset is relative to the module base address.
T able 2–1: Register Definitions
Address
(hexa-
Register
ID Register 0000 RO 101 1 1111 1111 1100 (hexadecimal BFFD)
Device Type 0002 RO See Device Type definition below
Status 0004 R Defined by state of interface
Control 0004 W Defined by state of interface
Offset 0006 WO Not used
Protocol 0008 RO 1111 0111 1111 1111 (hexadecimal F7FF)
Response 000A RO Defined by state of the interface
Data High 000C Not used
decimal)
Type Value (Bits 15–0)
2–4
Data Low 000E W Not fixed; command-dependent
Data Low 000E R Not fixed; command-dependent
RO is Read Only
WO is Write Only
R is Read
W is Write
VX4780 16-Channel Signal Conditioner User Manual
The Register Bit definitions are listed in Table 2–2:
T able 2–2: Register Bit Definitions
Register Bit Definition
ID hexadecimal BFFD
Protocol hexadecimal F7FF
Device hexadecimal F4F3
Operating Basics
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Command Syntax
Command protocol and syntax for the VX4780 Signal Conditioner are as
follows:
H A command string consists of a string of ASCII-encoded characters
The command string is buffered until the terminator is encountered, at which
time the entire string is processed.
H In addition to terminating a command, the semi-colon character directs the
terminated by a <program message terminator>. The <program message
terminator> is optional white space, followed by any one of the following
command terminations:
a line feed <LF> or new line <NL> character (hexadecimal 0A, decimal
10)
the END bit set
the END bit with a line feed <LF> or new line <NL>
SCPI command parser to interpret the next command with the assumption
that all characters up to and including the last colon in the previous
command have just been parsed.
This does not apply to semicolon characters specified in a SCPI <channel_list>.
The following example illustrates the use of the semi-colon as a command
terminator.
The commands:
input:state on,(@1,2)<LF>
input:gain 1,(@1:10)<LF>
input:att:state off,(@1,2)<LF>
are equivalent to the following command:
input:state on,(@1,2); gain 1,(@1:10); att:state
off,(@1,2)<LF>
After a line feed or END bit is used to terminate a command, the parser no
longer makes the assumption described above. Thus, after the command
input:coupling DC,(@1); filter:lpass:Freq 100e3,(@1)<LF>
is parsed, the command
gain 1,(@1:10)<LF>
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