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.
VX4780 16-Channel Signal Conditioner User Manual
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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.
VX4780 16-Channel Signal Conditioner User Manual
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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
VX4780 16-Channel Signal Conditioner User Manual
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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
VX4780 16-Channel Signal Conditioner User Manual
2–5
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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Command Syntax
is no longer valid. Note that <LF> in these examples represents a single line feed
character.
H White space characters can be used to make a command string more
readable. These characters are ASCII-encoded bytes in the range hexadecimal 00–09 and 0B–20 (decimal 0–9 and 11–32). This range includes the
ASCII control characters and the space, but excludes the line feed <NL>.
White space characters are ignored when legally encountered in a command
string. White space is allowed anywhere in a command string, except for the
following:
Within a program mnemonic (for example IN PUT)
Around a colon (:) mnemonic separator (for example INPUT: STATE)
Between a mnemonic and a (?) (for example *TST ?)
Following an asterisk (for example * TST?)
Within a number (for example 12 34)
At least one white space character is required between a command/query header
and its associated arguments. For example in the command
input:filter:lpass:freq 10e3,(@1:10)
the command header is the string “input:filter:lpass:freq”. The arguments
associated with this command header are the number “10e3” and the channel list
“(@1:10)”. At least one white space character must be sent before the first
argument.
H All characters in a command can be sent in either upper or lower case form.
H Multiple data parameters passed by a command are separated by a comma
(,).
H A question mark (?) following a command indicates that a response will be
returned. All responses from the module are terminated with a carriage return
<CR> and a line feed <LF> (hexadecimal 0A) character.
H In the command descriptions, the following special characters are used.
Except for the colon (:), these characters are not part of the command and
should not be sent. If an optional field is omitted, the default for the
command is applied.
[ ] Brackets indicate an optional field
3–2
| A bar indicates a logical OR choice
: A colon is used to separate command fields
< > Field indicator
VX4780 16-Channel Signal Conditioner User Manual
Command Syntax
Syntax Example
SCPI/IEEE 488.2
Command Elements
Capital letters indicate the minimum required characters which need to be sent.
Lower case letters are optional.
For example, the syntax of the lowpass filter cutoff frequency selection
command is given as:
INPut:FILTer:LPASs:FREQuency
<cutoff_frequency>,<channel_list>
where <cutoff_frequency> is a <nrf> field that specifies the filter cutoff
frequency, and <channel_list> specifies the channels to be affected.
Each of the following is a valid form of this command:
input:filter:lpass:frequency 1e3,(@1:5)
inp:filt:lpas:freq 1e3,(@1:5)
INPUT:FILT:LPASS:FREQ 1e3,(@1:5)
Input:Filter:Lpass:Frequency maximum,(@1:5)
Input:Filter:Lpass:Frequency max,(@1:5)
The definition of elements used in SCPI/IEEE-488.2 commands and command
descriptions is as follows:
<NR1>
ASCII integer representation of a decimal number.
<NRf>
ASCII integer, fixed point or floating point representation of a decimal
number.
The ASCII strings MAXimum, MINimum, and DEFault may also be
specified in a <NRf> field. If MAXimum is specified for a command
parameter, the parameter is set to the maximum allowed value. If MINimum
is specified for a command parameter, the parameter is set to the minimum
allowed value. If DEFault is specified for a command parameter, the
parameter is set to the value assigned at power-on.
The following are example commands that use the MAXimum, MINimum
and DEFault ASCII strings.
VX4780 16-Channel Signal Conditioner User Manual
3–3
Command Syntax
Command Description
input:filter:lpass:Freq
min,(@1:10)
input:gain maximum,(@16) Set the gain of channel 16 to the maximum allowed value,
input:gain def,(@1:16) Set the gain of all channels to the gain setting used at
Set the lowpass filter cutoff frequency of channels 1 through 10
to the minimum allowed value, 468 Hz.
100 V/V .
power-on, 1 V/V .
<channel_list>
A <channel_list> is a list of channel numbers on a VX4780 Module. When
used in a command, the <channel_list> specifies which channels the
command applies to. When used in a query, the <channel_list> specifies
which channels’ status to report. The channel numbers in the channel list
must be in the range of 1 through 16. The syntax of a <channel_list> is
described by the following diagram:
<channel_list>
,
( @
<channel_range>
)
A channel_range may consist of a single channel number or a range of
channel numbers. A range of channel numbers is indicated by two channel
numbers separated by a colon (:) character.
The following are examples of valid <channel_list>s for the VX4780.
<channel_list> Channels Specified
(@1) Channel number 1
(@1,2,16) Channels 1, 2 and 16
(@1:8) Channels 1 through 8
(@3,9:16) Channels 3 and 9 through 16
3–4
VX4780 16-Channel Signal Conditioner User Manual
Command Syntax
output queue
The Output queue of the VX4780 is used to return replies to queries. Bit 4
(the MAV bit) of the Status Byte register is set to indicate that this queue is
not empty. The DOR bit in the VXI Response register is also set to indicate
that this queue is not empty. The commander of the VX4780 monitors the
DOR bit to determine when it may read a message from the Output queue.
error/event queue
When the command parser detects a syntax error or data range error, it places
an error message describing the error in the Error/Event queue. Bit 2 of the
Status Byte Register is set to indicate that this queue is not empty. Bit 5 of
the Standard Event Status Register (the Command Error bit) is set if the
parser detects a syntax error. Bit 4 of the Standard Event Status register (the
Execution Error bit) is set if the parser detects a numeric argument that is out
of range. When a SYSTem:ERRor? query is received, an error message is
dequeued from the Error/Event queue and placed in the Output queue.
VX4780 16-Channel Signal Conditioner User Manual
3–5
Functional Command Groups
This section lists the VX4780 system and module commands.
System Commands
The following low-level commands are typically sent by the module’s commander, and are transparent to the user of the module. Exceptions are the Read STB
command and the Clear command. These commands are typically sent by
commanders that serve as an IEEE-488-to-VXIbus word serial interface. This
type of commander maps IEEE-488 addresses to VXIbus logical addresses.
When a IEEE-488 Serial Poll is issued on the IEEE-488 bus, the commander
typically sends a VXI Read STB command to the corresponding VXI logical
address. When a IEEE-488 Selected Device Clear command is sent on the
IEEE-488 bus, the commander typically sends a VXIbus Clear command to the
corresponding VXI logical address.
Most commanders or Slot 0 devices have specific ASCII commands that cause
the commander to send one of these low level commands to a specified
instrument. Refer to the operating manual of the commander or Slot 0 device for
information on these commands.
Command Effect
Begin Normal
Operation
Byte Available Transfers module commands to this module.
Byte Request Requests the module to return a byte of data from the output queue.
Clear The module clears its VXIbus interface and any pending commands.
Clear Lock Clears the Lock bit of the Response register.
Read Protocol The module returns its protocol to its commander.
Read STB The module returns its VXI status byte to its commander.
Set Lock Set the Lock bit of the Response register.
Trigger Accepted, but has no effect on the VX4780 Module.
The module begins operation if it has not already done so.
Current module operations are unaffected.
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Syntax and Commands
Module Commands
A summary of the VX4780-specific and IEEE-488.2 Common Commands is
listed in Tables 3–1 and 3–2 below. The next section, Command Descriptions,
includes detailed descriptions of each command. Appendix C: Examples shows
examples of command usage.
T able 3–1: Summary of VX4780–Specific SCPI Commands
Subsystem
Command
DIAGnostic Diagnostic commands.
INPut Control input isolation relays, input coupling, attenuators, variable
OUTPut Control output isolation relays.
ST ATus Status register functions: OPERation, QUESstionable.
SYSTem System-level functions: ERRor?, PRESet, VERSion?
Functions Controlled
gain amplifier, and lowpass filter.
T able 3–2: Summary of IEEE-488.2 Common Commands
Command/Syntax Description
Clear Status
*CLS
Standard Event Status Enable
*ESE <NRf>
Standard Event Status Enable Query
*ESE?
Standard Event Status Register Query
*ESR?
Identification Query
*IDN?
Operation Complete
*OPC
Operation Complete Query
*OPC?
Reset*
*RST
Clears the SCPI and IEEE 488.2 event registers
and the SCPI Error/Event queue, and the Output
queue.
Sets the contents of the Standard Event Status
Enable register.
Returns the current value of the Standard Event
Status Enable register in <nr1> format.
Returns the current value of the Standard Event
Status register in <nr1> format, then set the
contents of this register to 0.
Returns an ASCII string in the Output queue which
identifies the board.
Sets bit 0 (the Operation Complete bit) of the
Standard Event Status register when all pending
device operations have been completed.
Places the ASCII character 1 in the Output queue
when all pending device operations have been
completed.
The VX4780 is placed in its power-on state with
some exceptions.
3–8
VX4780 16-Channel Signal Conditioner User Manual
Syntax and Commands
T able 3–2: Summary of IEEE-488.2 Common Commands (Cont.)
Command/Syntax Description
Service Request Enable
*SRE <NRf>
Sets the contents of the Service Request Enable
register.
Service Request Enable Query
*SRE?
Read Status Byte Query
*STB?
Self Test Query
*TST?[<channel_list>]
Wait-to-Continue
*WAI
Returns the current value of the Service Request
Enable register in <nr1> format.
Returns the current value of the Status Byte
register in <nr1> format.
Performs a self test of the VX4780. Place a “0” or
“1” into the output queue to indicate whether the
self test passed or failed.
Does not execute any further commands or queries
until all pending operations have been completed.
VX4780 16-Channel Signal Conditioner User Manual
3–9
Command Descriptions
This section lists the VX4780-specific SCPI commands and queries in alphabetic
order. The IEEE-488.2 Common Commands are listed in the next section. A
summary listing of the SCPI command set for the VX4780 is as follows:
INPut:ATTenuation <attenuation>,<channel_list>,
INPut:COUPling DC | AC | GROund, <channel_list>,
INPut:FILTer:LPASs:FREQuency <cutoff_frequency>,<channel_list>
INPut:GAIN <gain>,<channel_list>,
INPut:GAIN:TRIM <gainadj>,<channel_list>,
INPut:STATe <state>,<channel_list>
OUTPut:STATe <state>,<channel_list>,
OUTPut:OFFSet:TRIM <offsetadj>,<channel_list>
STATus:OPERation:CONDition?
STATus:OPERation:ENABle
STATus:OPERation[:EVENt?]
STATus:QUEStionable:CONDition?
STATus:QUEStionable:ENABle
STATus:QUEStionable[:EVENt?]
SYSTem:ERRor?
SYSTem:PRESet
SYSTem:VERSion?
VX4780 16-Channel Signal Conditioner User Manual
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Command Descriptions
INPut
Command Syntax
Query Syntax
Query Response
*RST Value
Limits
Related Commands
INPut:
ATTenuation <attenuation>,<channel_list>
INPut:ATTenuation? <channel_list>
or
INPut:ATTenuation? MAXimum | MINimum | DEFault [,<channel_list>]
The query returns the attenuation setting in units of volt/volt (v/v) for each
channel specified.
The attenuation of all channels is set to 10.
N/A
INPut:GAIN <channel_list>
INPut:GAIN:TRIM <channel_list>
INPut:ATTenuation:STATe <channel_list>
Description
Each channel contains an input attenuator followed by a variable gain amplifier
followed by a low pass filter with programmable cutoff frequency.
The INPut:ATTenuation command is used to set the input attenuator of each
channel to divide the input signal by 10 or 100. The INPut:ATTenuation:STATe
command is used to either insert the attenuator into the signal path or bypass it.
The attenuation is specified in units of volt/volt, and must be 10 or 100. An error
is placed in the Error/Event queue if any other value is specified. An attenuation
of 100 is only permitted when the low pass filter is programmed for a cutoff
frequency of 7.02 kHz or less. An error is placed in the Error/Event queue if an
attenuation of 100 is specified for a channel that has been programmed with a
low pass filter cutoff frequency greater than 7.02 kHz.
The <attenuation> parameter consists of a decimal ASCII number or one of the
ASCII strings MAXimum, MINimum, or DEFault. The ASCII string MAXimum specifies an attenuation of 100. The ASCII strings MINimum and DEFault
specify an attenuation of 10. If the input attenuator is bypassed, the overall
channel gain is equal to the gain of the variable gain amplifier. If the input
attenuator is inserted into the signal path, the overall channel gain is equal to the
gain of the variable gain amplifier divided by the attenuator attenuation setting.
For example, if the attenuator of channel 1 is inserted into the signal path and set
3–12
VX4780 16-Channel Signal Conditioner User Manual
Examples
Command Descriptions
to divide the signal by 10 and the gain of the variable gain amplifier is set to 50,
the overall channel gain is equal to 50/10 = 5.
Command Response
input:Att 100,(@1:16) Set the attenuators of channels 1 through 16 to divide by
100.
input:Attenuation max,(@1:16) Set the attenuators of channels 1 through 16 to divide by
100.
inp:att min,(@1,2,3) Set the attenuators of channels 1 through 3 to divide by
10.
Command Syntax
Query Syntax
Query Response
*RST Value
Limits
Related Commands
Description
INPut:COUPling DC | AC | GROund, <channel_list>
INPut:COUPling? <channel_list>
“DC”, “AC”, or “GRO” is returned for each channel specified in the query,
indicating the state of the input coupling relay for each channel.
All inputs are AC coupled.
N/A
INPut:STATe
If DC coupling is specified in this command, the inputs of the specified
channel(s) are connected through the input isolation relays directly to the input
attenuator(s). If AC coupling is specified, the inputs of the specified channel(s)
are switched through the input isolation relays, then through coupling capacitors
to the input attenuators(s). The INPut:STATe command is used to control the
state of the input isolation relays.
If GROund is specified in the INPut:COUPling command, the input isolation
relays are opened and the amplifier inputs of the specified channel(s) are
switched to ground.
VX4780 16-Channel Signal Conditioner User Manual
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Command Descriptions
Examples
Command Response
input:coupling dc,(@1:16);
state on,(@1:16)
input:coupling ac,(@1:16);
state on,(@1:16)
DC couple the inputs of all 16 channels.
AC couple the inputs of all 16 channels.
Command Syntax
Query Syntax
Query Response
input:coupling ground,
(@1:6,10)
Open the isolation relays of channels 1 through 6 and 10
and connect the inputs of these channels to ground.
INPut:FILTer:LPASs:FREQuency <cutoff_frequency>,<channel_list>
INPut:FILTer:LPASs:FREQuency? <channel_list>
or
INPut:FILTer:LPASs:FREQuency? MAXimum | MINimum | DEFault
[,<channel_list>]
The response to the first query listed above is the frequency setting of the
lowpass filter cutoff in Hz for each channel specified in the query.
The response to the second query listed above is the maximum, minimum,
or default frequency setting of the lowpass filter cutoff of the specified
channels. If no <channel_list> is specified, the value associated with the
ASCII strings MAXimum, MINimum or DEFault when specified in the
INPut:FILTer:LPASs:FREQuency command is returned.
3–14
*RST Value
Limits
Related Commands
Description
The cutoff frequency of the lowpass filter of all channels is set to 468 Hz.
N/A
N/A
Each channel contains a 4th order Bessel low pass filter. The cutoff frequency of
each filter is command selectable from 468 Hz to 7.02 kHz in 468 Hz steps, and
from 7.13 kHz to 107 kHz in 7.13 kHz steps. Cutoff frequencies greater than 468
Hz and less than 107 kHz are rounded to the closest realizable value. This value
is returned in the response to an INPut:FILTer:LPASs:FREQuency? query. An
error is placed in the Error/Event queue if a frequency of less than 468 Hz or
greater than 107 kHz is specified. The <cutoff_frequency> argument consists of
a decimal ASCII number (followed by optional units of “Hz” or “kHz”), or one
of the ASCII strings MAXimum, MINimum, or DEFault. MAXimum specifies a
VX4780 16-Channel Signal Conditioner User Manual
Command Descriptions
cutoff frequency of 107 kHz. The ASCII strings MINimum and DEFault specify
a cutoff frequency of 468 Hz.
Examples
The following four commands are equivalent and set the cutoff frequencies of all
16 channels to 107 kHz.
input:filter:lpass:Freq 107e3,(@1:16)
input:filter:lpass:Freq maximum,(@1:16)
input:filter:lpass:Freq 107kHz,(@1:16)
input:filter:lpass:Freq 107000Hz,(@1:16)
The next five commands are equivalent and set the cutoff frequencies of all 16
channels to 468 Hz.
input:filter:lpass:Freq 468Hz,(@1:16)
input:filter:lpass:Freq min,(@1:16)
input:filter:lpass:Freq minimum,(@1:16)
input:filter:lpass:Freq default,(@1:16)
input:filter:lpass:Freq 468,(@1:16)
The next example sets the cutoff frequency of the filters of channels 1, 5, and 10
to 7.02 kHz, then verifies it.
Command Response
input:filter:lpass:Freq 7e3,
(@1,5,10)
no response
input:filter:lpass:freq? (@1) 7020<cr><lf>
Command Syntax
Query Syntax
INPut:GAIN <gain>,<channel_list>
INPut:GAIN? <channel_list>
or
INPut:GAIN? MAXimum | MINimum | DEFault [,<channel_list>]
Query Response
The response to the INPut:GAIN? <channel_list> query is the gain setting in
volt/volt for each channel specified in the query.
The response to the Maximum/Minimum/Default query is the maximum,
minimum, or default gain setting(s) of the specified channel(s). If no <channel_list> is specified, the value associated with ASCII strings MAXimum,
MINimum, or DEFault (when specified in the INPut:GAIN command) is
returned.
VX4780 16-Channel Signal Conditioner User Manual
3–15
Command Descriptions
*RST Value
Limits
Related Commands
Description
The gain of all channels is set to 1.
N/A
INPut:ATTenuation <channel_list>,
INPut:ATTenuation:STATe <channel_list>,
INPut:GAIN:TRIM <channel_list>
Each channel consists of an input attenuator followed by a variable gain
amplifier and low pass filter. The input attenuator of each channel may be set to
divide the input signal by 10 or 100 with the INPut:ATTenuation command. The
input attenuator of each channel may be inserted into the signal path or bypassed
with the INPut:ATTenuation:STATe command. The gain of the variable gain
amplifier in units of volt/volt is set to the <gain> parameter of the INPut:GAIN
command. The gain specified in this command must be one of the following
values: 1.0, 2.0, 5.0, 10.0, 20.0, 50.0 or 100.0. An error is placed in the
Error/Event queue if any other gain value is specified.
The <gain> parameter consists of a decimal ASCII number or one of the ASCII
strings MAXimum, MINimum, or DEFault. The ASCII string MAXimum
specifies a gain of 100. The ASCII strings MINimum and DEFault specify a gain
of 1.
Examples
If the input attenuator is bypassed, the overall channel gain is equal to the gain of
the variable gain amplifier. If the input attenuator is inserted into the signal path,
the overall channel gain is equal to the gain of the variable gain amplifier divided
by the attenuator attenuation setting. For example, if the attenuator of channel 1
is inserted into the signal path and set to divide the signal by 10 and the gain of
the variable gain amplifier is set to 50, the overall channel gain is equal to
50/10 = 5.
The following three examples are equivalent and set the gain of all 16 variable
gain amplifiers to 100. The attenuators of all 16 channels are bypassed, so the
overall gain of all 16 channels is set to 100.
Command Response
input:att:State off,(@1:16) Bypass the input attenuators of channels 1 through 16.
input:gain 100,(@1:16) Set the gain of all 16 variable gain amplifiers to 100.
input:gain maximum,(@1:16) Set the gain of all 16 variable gain amplifiers to 100.
input:gain 1e2,(@1:16) Set the gain of all 16 variable gain amplifiers to 100.
The following are all valid examples of the input:gain command.
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VX4780 16-Channel Signal Conditioner User Manual
Command Descriptions
Command Response
input:gain 100,(@1:16) Set the gain of channels 1 through 16 to 100 V/V.
input:gain max,(@1:16) Set the gain of channels 1 through 16 to 100 V/V.
inp:gain 1,(@1,2,3) Set the gain channels 1 through 3 to 1 V/V .
input:gain 5,(@1:16) Set the gain of channels 1 through 16 to 5 V/V.
input:gain? (@1:8) 5, 5, 5, 5, 5, 5, 5, 5<cr>,<lf>
Command Syntax
Query Syntax
Query Response
*RST Value
Limits
Related Commands
INPut:GAIN:TRIM <gainadj>,<channel_list>
INPut:GAIN:TRIM? <channel_list>
or
INPut:GAIN:TRIM? MAXimum | MINimum | DEFault [,<channel_list>]
The response to the first query listed above is the gain trim setting in parts per
million (ppm) for each channel specified in the query.
The response to the second query listed above is the maximum, minimum or
default gain trim settings of the specified channels. If no <channel_list> is
specified, the value associated with the ASCII strings MAXimum, MINimum or
DEFault when specified in the INPut:GAIN:TRIM command is returned.
The input gain trim of all channels is set to 0 ppm.
N/A
INPut:GAIN <channel_list>,
INPut:ATTenuation <channel_list>,
INPut:ATTenuation:STATe <channel_list>
Description
VX4780 16-Channel Signal Conditioner User Manual
Each channel contains a digital-to-analog converter (DAC) used to calibrate the
overall channel gain. The INPut:GAIN:TRIM command provides access to these
DACs. A value corresponding to the <gainadj> parameter is added to the value
from NOVRAM that is normally loaded into the converter. The result is loaded
into the gain trim DAC(s) of the channel(s) specified in the <channel_list>.
This feature is useful for performing a system level calibration of gain. For
example if the gain of a sensor connected to a VX4780 input is 0.5% low, the
INPut:GAIN:TRIM command can be used to compensate for this error by
increasing the VX4780 gain by 0.5%. The resolution of the gain correction can
3–17
Command Descriptions
be determined for a particular channel can be determined by reading NOVRAM
address (chan-1)*12 and dividing by 100. The result is the gain trim resolution in
ppm. Nominally the gain trim resolution is 16.89 ppm. The range of the
correction factors that can be specified in the INPut:GAIN:TRIM command is
±10000 ppm = ±1%. Values specified outside of this range will cause an error
condition.
Examples
Command Syntax
Query Syntax
Query Response
*RST Value
The gain of a sensor connected to VX4780 channel 1 input is determined to be
0.567% low. The following example increases the gain VX4780 channel 1 by
0.567% to compensate for the sensor gain error.
Command Response
input:gain:trim 5670ppm,(@1) Increase the gain of VX4780 channel 1 by 0.567%.
INPut:STATe <state>,<channel_list>
INPut:STATe? <channel_list>
This query returns the state of the input isolation relay for each channel specified
in the query. A 1 in the query response indicates that an isolation relay is closed,
and that the signal conditioning channel input is connected to the front panel
input connector. A 0 in the query response indicates that the input isolation relay
is opened, and the signal conditioning channel input is disconnected from the
front panel input connector.
The input isolation relays for all channels are opened.
3–18
Limits
Related Commands
Description
N/A
INPut:COUPling
Each channel contains an input isolation relay. When closed, this relay connects
the positive and negative channel inputs on one of the front panel input
connectors to the input of the signal conditioning circuitry for that channel.
When this relay is opened, the front panel inputs are disconnected from the input
of the signal conditioning circuitry.
The <state> argument in this command can consist of a decimal ASCII number
or the ASCII strings ON or OFF. The ASCII string ON or non zero ASCII
number specify that the input isolation relay(s) of the channel(s) specified in the
channel list are to be closed. The ASCII string OFF or the number zero specify
VX4780 16-Channel Signal Conditioner User Manual
Command Descriptions
that the input isolation relay(s) of the channel(s) specified in the channel list are
to be opened.
The input isolation relays are also opened when a INPut:COUPling
GROund,<channel_list> command is received.
When power is removed from the VXIbus chassis containing the VX4780,
VMEbus signal ACFAIL* is asserted. In response to this signal, the VX4780
opens all input and output isolation relays.
Examples
The following two examples open the input isolation relays of all channels.
Command Response
input:state off,(@1:16) no response
input:State 0.0,(@1:16) no response
The next two examples are equivalent and close the input isolation relays of all
channels.
Command Response
input:state 1,(@1:16) no response
input:state on,(@1:16) no response
The next example queries the state of the input isolation relays of channels 3, 4,
and 15. The query response indicates that the input isolation relays for these
channels are closed.
Command Response
input:state? (@3:4,15) 1, 1, 1<cr><lf>
VX4780 16-Channel Signal Conditioner User Manual
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Command Descriptions
OUTPut
Command Syntax
Query Syntax
Query Response
*RST Value
Limits
Related Commands
Description
OUTPut:STATe <state>,<channel_list>
OUTPut:STAT e? <channel_list>
This query returns the state of the output isolation relay for each channel
specified in the query. A 1 in the query response indicates that an output
isolation relay is closed, and that the signal conditioning channel output is
connected to the front panel output connector. A 0 in the query response
indicates that the output isolation relay is open, and the signal conditioning
channel output is disconnected from the front panel output connector.
The output isolation relays for all channels are opened.
N/A
N/A
Each channel contains an output isolation relay. When closed, this relay connects
the output of the signal condition circuitry for that channel to a front panel
output connector. When this relay is opened, the channel output is disconnected
from the front panel output connector. The <state> argument in this command
can consist of a decimal ASCII number or the ASCII strings ON or OFF. The
ASCII string ON or non-zero ASCII number specify that the output isolation
relay(s) of the channel(s) specified in the channel list are to be closed. The
ASCII string OFF or the number zero specify that the output isolation relay(s) of
the channel(s) specified in the channel list are to be opened.
3–20
Examples
When power is removed from the VXIbus chassis containing the VX4780,
VMEbus signal ACFAIL* is asserted. In response to this signal, the VX4780
opens all input and output isolation relays.
The following two examples open the output isolation relays of all channels.
Command Response
output:state off,
(@1:16)
output:State 0.0,
(@1:16)
no response
no response
VX4780 16-Channel Signal Conditioner User Manual
Command Descriptions
The next two examples are equivalent and close the output isolation relays of all
channels.
Command Response
output:state 1,(@1:16) no response
Command Syntax
Query Syntax
output:state
on,(@1:16)
no response
The next example queries the state of the output isolation relays of channels 3, 4,
and 15. The query response indicates that the output isolation relays for these
channels are closed.
Command Response
output:state?
(@3:4,15)
1, 1, 1<cr><lf>
OUTPut:OFFSet:TRIM <offsetadj>,<channel_list>
OUTPut:OFFSet:TRIM? <channel_list>
or
OUTPut:OFFSet:TRIM? MAXimum | MINimum | DEFault [,<channel_list>]
Query Response
The response to the first query listed above is the output DC offset trim setting in
volts for each channel specified in the query.
The response to the second query listed above is the maximum, minimum or
default output DC offset trim settings of the specified channels. If no <channel_list> is specified, the value associated with the ASCII strings MAXimum,
MINimum or DEFault when specified in the OUTPut:OFFSet:TRIM command
is returned.
*RST Value
Limits
Related Commands
The output offset trim of all channels is set to 0 volts.
N/A
N/A
VX4780 16-Channel Signal Conditioner User Manual
3–21
Command Descriptions
Description
Each channel contains a DAC used to null DC offset errors at the channel output.
The OUTPut:OFFSet:TRIM command provides access to these DACs. A value
corresponding to the <offsetadj> parameter is added to the offset error value
from NOVRAM corresponding to the current gain setting. The result is used to
calculate a load value for the offset trim DAC(s) of the channel(s) specified in
the <channel_list>.
This feature is useful for performing a system level calibration of DC offset. For
example if a sensor connected to a VX4780 input produces an offset error of
+10 mV at the VX4780 channel output, the OUTPut:OFFSet:TRIM command
can be used to compensate for this error by adding a –10 m VDC correction to
the channel output signal. The resolution of the offset correction that the
VX4780 can apply increases as the magnitude of the correction increases
according to the following formula:
R = (128 - x) * ref / 16320
where
x = –1 + round down (128 * (1 – |correction| / ref))
correction = the correction to apply in volts.
ref = the contents of NOVRAM location 192 + (channel-1)*12 divided by
100000. This value is nominally 0.395 volts.
Examples
R = resolution of the DC correction in volts.
For example, for ref = 0.395 and a desired correction of 0.01 volts, x = 123 =>
R = 121 µV
The range of the correction factors that can be specified in the INPut:OFFSet:TRIM command is ±0.2 V. Values specified outside of this range will cause
an error condition.
In the following example 0V is input to channel 1 of the VX4780 and a voltmeter measures 300 µV at the channel 1 output.
Command Response
output:offset:trim
-300e-6,(@1)
Subtracts 300 V from the DC offset at the output of channel
1, nulling this offset error.
3–22
VX4780 16-Channel Signal Conditioner User Manual
STATus
Command Descriptions
Command Syntax
*RST Value
Limits
Related Commands
Description
Examples
STATus
:OPERation
:CONDition?
0
N/A
N/A
This query returns the contents of the SCPI Status Operation Condition register.
For the VX4780, the value of this register is always equal to 0.
Command Response
status:operation:
condition?
00000
Command Syntax
Query Syntax
*RST Value
Limits
Related Commands
STATus
:OPERation
:ENABle
STATus:
OPERation
:ENABle?
0
N/A
N/A
VX4780 16-Channel Signal Conditioner User Manual
3–23
Command Descriptions
Description
Examples
Command Syntax
*RST Value
Limits
This command sets the contents of the SCPI Status Operation Event Enable
register.
Command Response
status:operation:
enable 1
stat:oper:enab? 00001
STATus
:OPERation
[:EVENt?]
0
N/A
no response
Related Commands
Description
Examples
Command Syntax
*RST Value
Limits
N/A
This query returns the contents of the SCPI Status Operation Event register. For
the VX4780, the value of this register is always equal to 0.
Command Response
status:operation:
event?
STATus
:QUEStionable
:CONDition?
0
N/A
00000
3–24
VX4780 16-Channel Signal Conditioner User Manual
Command Descriptions
Related Commands
Description
Examples
Command Syntax
Query Syntax
N/A
This query returns the contents of the SCPI Status Questionable Condition
register. For the VX4780, the value of this register is always equal to 0.
Command Response
status:questionable:
condition?
STATus
:QUEStionable
:ENABle
STATus
:QUEStionable
:ENABle?
00000
Query Response
*RST Value
Limits
Related Commands
Description
Examples
Indicates whether the Status Operation Event is enabled.
0
N/A
N/A
This command sets the contents of the SCPI Status Operation Event Enable
register.
Command Response
status:questionable:
enable 1
stat:ques:enab? 00001
No response
VX4780 16-Channel Signal Conditioner User Manual
3–25
Command Descriptions
Command Syntax
*RST Value
Limits
Related Commands
Description
Examples
STATus
:QUEStionable
[:EVENt?]
0
N/A
N/A
This query returns the contents of the SCPI Status Questionable Event register.
For the VX4780, the value of this register is always equal to 0.
Command Response
status:questionable:
event?
00000
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VX4780 16-Channel Signal Conditioner User Manual
SYSTem
Command Descriptions
Command Syntax
Query Response
SYSTem
:ERRor?
0,“No error”
Number 10 messages are placed in the Error/Event queue during self test to
indicate which channels passed self test. See the description of the “*TST?”
query for more information on these error messages.
10,“Test passed; Novram checksum, Constant type/Channel mask: Gain/x,
Offset/x
10,“Test passed; Offset trim dac(s), Channel mask: x”
10, “Test passed; Input test voltage, Input/Channel mask: Neg/x, Pos/x
10,“Test passed; Attenuator bypass with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
10,“Test passed; Attenuator bypass with stored cal, Input/Channel mask: Neg/x,
Pos/x”
10,“Test passed; /10 Attenuator(s) with nominal cal, Input/Channel mask: Neg/x,
Pos/x”
10,“Test passed; /10 Attenuator(s) with stored cal, Input/Channel mask: Neg/x,
Pos/x”
10,“Test passed; /100 Attenuator(s) with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
10,“Test passed; /100 Attenuator(s) with stored cal, Input/Channel mask: Neg/x,
Pos/x”
10,“Test passed; Gain trim dac(s), Channel mask: x”
10,“Test passed; Low pass filter(s), Tuning bit/Channel mask: 0/x, 1/x, 2/x, 3/x,
4/x”
10,“Test passed; AC coupling capacitors, Input/Channel mask: Neg/x, Pos/x”
10,“Test passed; Variable gain amplifier with nominal cal, Channel mask: 2/x,
5/x, 10/x, 20/x, 50/x, 100/x”
10,“Test passed; Variable gain amplifier with stored cal, Gain/Channel mask:
2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
-102,“Syntax error; Unexpected x detected while ...”
VX4780 16-Channel Signal Conditioner User Manual
3–27
Command Descriptions
–108,“Parameter count exceeded for xxxx command”
–109,“Missing parameter for xxxx command”
–121,“Invalid character in number”
–123,“Exponent too large
–221,“Settings conflict; /100 attenuator setting conflict with upper range filter
cutoff frequency, Channel mask x”
–222,“Data out of range; Minimum cutoff frequency is 468 Hz”
–222,“Data out of range; Maximum cutoff frequency is 107 KHz”
–222,“Data out of range; Maximum gain is 100”
–222,“Data out of range; Minimum gain is 1”
–222,“Data out of range”
–222,“Data out of range; Illegal channel number: x”
–224,“Illegal parameter value; Allowed gains are 1 and 10”
–224,“Illegal parameter value; Allowed gains are 1,2,5 and 10”
–224,“Illegal parameter value; Allowed gains are 1 to 100 in 1/2/5 steps”
–224,“Illegal parameter value; Allowed attenuations are 10 and 100”
Number -330 messages are placed in the Error/Event queue during self test to
indicate which channels failed self test. See the description of the *TST? query
for more information on these error messages.
–330,“Self-test failed; self test a/d converter failure”
–330,“Self-test failed; Novram checksum, Constant type/Channel mask: Gain/x,
Offset/x
–330,“Self-test failed; Offset trim dac(s), Channel mask: x”
–330, “Self-test failed; Input test voltage, Input/Channel mask: Neg/x, Pos/x
–330,“Self-test failed; Attenuator bypass with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
–330,“Self-test failed; Attenuator bypass with stored cal, Input/Channel mask:
Neg/x, Pos/x”
3–28
–330,“Self-test failed; /10 Attenuator(s) with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
VX4780 16-Channel Signal Conditioner User Manual
Command Descriptions
–330,“Self-test failed; /10 Attenuator(s) with stored cal, Input/Channel mask:
Neg/x, Pos/x”
–330,“Self-test failed; /100 Attenuator(s) with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
–330,“Self-test failed; /100 Attenuator(s) with stored cal, Input/Channel mask:
Neg/x, Pos/x”
–330,“Self-test failed; Gain trim dac(s) , Channel mask: x”
–330,“Self-test failed; Low pass filter(s), Tuning bit/Channel mask: 0/x, 1/x, 2/x,
3/x, 4/x”
–330,“Self-test failed; AC coupling capacitors, Input/Channel mask: Neg/x,
Pos/x”
–330,“Self-test failed; Variable gain amplifier(s) with nominal cal, Gain/Channel
mask: 2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
–330,“Self-test failed; Variable gain amplifier(s) with stored cal, Gain/Channel
mask: 2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
*RST Value
Limits
Related Commands
Description
Examples
–350,“Queue overflow; Error/event queue”
–350,“Queue overflow; Output queue”
The Error/Event queue is empty.
N/A
*ESR?,
*STB?
If an error condition is detected by the VX4780, it places an error message
describing the condition in the Error/Event queue. The SYSTem:ERRor? query
requests the VX4780 to remove the oldest message in the Error/Event queue and
place it into the Output queue. If the Error/Event queue is empty, a “No error”
message is placed in the Output queue.
Command Response
SYSTEM:ERROR? 0, “No error”
syst:err? -222,“Data out of range”
VX4780 16-Channel Signal Conditioner User Manual
3–29
Command Descriptions
Command Syntax
Query Syntax
*RST Value
Limits
Related Commands
Description
SYSTem:
PRESet
N/A
N/A
N/A
*RST
This command places the VX4780 in the power-on state. This command has the
same effect as the *RST command, with the following exceptions: the SYSTem:PRESet command clears
the Output queue,
the Error/Event queue,
the Standard Event Status Enable register,
Examples
Command Syntax
*RST Value
Limits
Related Commands
the SCPI Status Operational Enable register, and
the SCPI Status Questionable Enable register.
Command Response
system:preset No response
syst:pres No response
SYSTem
:VERSion?
N/A
N/A
None
3–30
VX4780 16-Channel Signal Conditioner User Manual
Command Descriptions
Description
Examples
This query returns the following ASCII string in the output queue:
”1994.0”
Command Response
system:version? "1994.0"
syst:vers? "1994.0"
VX4780 16-Channel Signal Conditioner User Manual
3–31
IEEE-488.2 Common Commands
This section lists the IEEE-488.2 common commands and queries recognized by
the VX4780.
*CLS
Clear Status. This commands clears the following:
Event Status register (ESR)
Error/Event queue
Output queue
*ESE <NRf>
Event Status Enable (ESE) command. This command defines the mask for
setting the Event Status Summary bit (bit 5) in the Status Byte register (*STB?).
The mask is logically ANDed with the Event Status register (*ESR?) to
determine whether or not to set the Event Status Summary bit. The mask can be
any numeric value from 0 to 255, corresponding to the encoded bits of the ESR
register. A “1” in a bit position enables reporting of the function. A “0” disables
it. The *ESE register is cleared at power-on, or by writing an *ESE 0 command
only. If <mask> is not specified, it defaults to 0.
For example, the command *ESE 37 (hexadecimal 25, binary 00010101) enables
setting the Event Status Summary bit whenever an operation is complete, a query
error is detected, or an execution error is detected.
*ESE?
Event Status Enable (ESE) query. This command returns the value of the Event
Status Enable register as a numeric value from 0 to 255. For example, a value of
32 (hexadecimal 40, binary 00100000) indicates that command error reporting is
enabled.
*ESR?
Event Status Register (ESR) query. This command returns the value of the Event
Status register. The *ESR command is destructively read (that is, read and
cleared). The Event Status Summary bit in the Status Byte (*STB?) is also
cleared by a read of the ESR. The ESR is set to 128 on power-on (bit 7) set. It is
VX4780 16-Channel Signal Conditioner User Manual
3–33
IEEE 488.2 Common Commands
cleared by an *ESR? or *CLS command only. When converted to a binary
number, the bits of the ESR correspond to:
bit 0 (LSB) Operation Complete
1 Request Control
2 Query error
3 Device Dependent error
4 Execution error
5 Command error
6 User Request
7 (MSB) Power On
The Error bits are set whenever the module detects an error. The error values
from –100 to –199 are Command errors. Error values from –200 to –299 are
Execution errors. Error values from –300 to –399 are Device Dependent errors.
Error values from –400 to –499 are Query errors (see the SYSTem:ERRor
command description).
The Request Control and User Request bits are unused, and are always reported
as zeroes.
*IDN?
*OPC
*OPC?
The Operation Complete bit is set in response to an *OPC command. A 1
indicates that the module has completed all pending commands and queries.
Identification query; This returns a 4-field response. Field 1 is the manufacturer,
field 2 the model, field 3 the serial number, and field 4 contains both the SCPI
and the firmware version levels. For the VX4780, the serial number field is
always a 0. The response syntax is:
TEKTRONIX,VX4780,0,SCPI:94.0 FV1.0<LF>
Operation Complete. This command causes the module to set the Operation
Complete bit in the Event Status register (ESR) when all pending commands and
queries are complete.
3–34
Operation Complete query. This command causes the module to place a “1” in
the Output queue when all pending commands and queries are complete. All
commands following *OPC are suspended until the pending operations are
VX4780 16-Channel Signal Conditioner User Manual
*RST
IEEE 488.2 Common Commands
complete. The *OPC? command does not affect the OPC bit in the Event Status
register.
Reset. This command places the VX4780 in the following state:
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
*SRE <mask>
This command does not clear the Error/Event queue, the Output queue or the
Standard Event Status Enable register.
Service Request Enable (SRE) register. This command defines a mask that is
ANDed with the contents of the Status Byte register. If the result of this
operation is non-zero, the VX4780 generates a VXI Request True interrupt. Bits
0, 1, 3, 6, and 7 of the SRE register are not used. Bits 2, 4, and 5 are set to
enable VXI Request True interrupts to be generated under the conditions listed in
the following table.
Bit No. Meaning
bit0 (LSB) Not used.
1 Not used.
2 The Error/Event queue contains one or more error messages.
3 Not used.
4 The Output queue contains one or more query responses.
5 The contents of the Standard Event Status register ANDed with the contents
of the Standard Event Status Enable register produces a non–zero result.
6 Not used.
7 Not used.
VX4780 16-Channel Signal Conditioner User Manual
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IEEE 488.2 Common Commands
*SRE?
*STB?
Service Request Enable (SRE) query. This command returns the value of the
Service Request Enable register as a numeric value from 0 to 255. Bit 6 is
unused, and is reported as zero.
Status Byte Query. This query returns the value of the Status Byte register as a
numeric value between 0 and 255. The Status Byte register contents (with the
exception of bit 6) are also returned in response to a VXI Read STB command.
Bit 6 is read destructively in response to a VXI Read STB command. Bit 6 is not
read destructively in response to a *STB? query. The Status Byte register is
encoded as follows:
Bit No. Meaning
bit 0 (lsb) Not used.
bit 1 Not used.
bit 2 Set when the Error/Event queue contains one or more error messages.
bit 3 Not used.
bit 4 Set when the Output buffer contains one or more query responses.
bit 5 Set when the contents of the Standard Event Status register ANDed with
the contents of the Standard Event Status Enable register produces a non
zero result.
bit 6 Set when the contents of bits 0 through 5 and bit 7 of the Status Byte regis-
ter ANDed with the contents of the Service Request Enable register produce
a non zero result.
If bit 6 becomes set, the VX4780 will generate a VXI Request True interrupt
on the VME interrupt level selected by its interrupt level select switch. If bit 6
becomes set and the Status Byte register is read using a VXI Read STB
command, bit 6 will be reported as being set. In response to subsequent VXI
Read STB commands, bit 6 will be reported as being cleared.
If bit 6 becomes set and the Status Byte register is read using a *STB?
query , bit 6 will be reported as being set. Bit 6 will continue to be reported as
set in response to *STB queries until the contents of bits 0 through 5 and bit
7 of the Status Byte register ANDed with the contents of the Service Request Enable register is equal to 0.
bit 7 Not used.
3–36
VX4780 16-Channel Signal Conditioner User Manual
*TST?
IEEE 488.2 Common Commands
*TST? [<channel_list>] Self Test Query.
In response to this query, the VX4780 performs a self test of the channels
specified in the <channel_list> argument. If no <channel_list> is specified, all
sixteen channels are tested. If the channel(s) pass self test, an ASCII “0” is
placed in the Output buffer and user defined messages describing the tests
performed are placed in the Error/Event queue. These error messages may be
read by issuing a SYSTem:ERRor? query or cleared with the *CLS command. If
one or more channels fail self test, an ASCII “1” is placed in the output buffer
and error message(s) describing the failure(s) are queued in the Error/Event
queue. These error messages may be read by issuing a SYSTem:ERRor? query.
When a *TST? command is issued to the VX4780, it opens the input and output
isolation relays of the channel(s) to be tested, then performs the following tests:
1. NOVRAM contains a set of DC offset calibration factors and gain calibra-
tion factors for each channel of the VX4780. Two calibration factor
checksums are stored for each channel, one for the DC offset calibration
factors and one for the gain calibration factors. This test calculates the
checksum of the DC offset and gain calibration factors and verifies that they
are equal to the stored checksums.
2. Each channel contains a d/a converter that is used to null the DC offset error
at the channel output for each setting of the variable gain amplifier. This test
verifies that these d/a converters are functioning properly.
3. During self test, a variable voltage source is applied to the inputs of each
channel being tested. This test verifies that the variable voltage source is
functioning properly.
4. The channel gain is measured and checked to be equal to 1 after setting the
channel to the following state: DC coupled, Attenuator bypassed, variable
gain amplifier gain set to 1, low pass filter cutoff frequency set to 107 kHz.
5. The channel gain is measured and checked to be equal to 0.1 after setting the
channel to the following state: DC coupled, Attenuator inserted and set to
divide by 10, variable gain amplifier gain set to 1, low pass filter cutoff
frequency set to 107 kHz.
6. The channel gain is measured and checked to be equal to 0.01 after setting
the channel to the following state: DC coupled, Attenuator inserted and set to
divide by 100, variable gain amplifier gain set to 1, low pass filter cutoff
frequency set to 107 kHz.
Tests 4, 5, and 6 are performed with nominal calibration factors loaded, then
repeated using stored calibration factors. If a test passes with nominal calibration
factors and fails with stored calibration factors, this indicates that an incorrect
VX4780 16-Channel Signal Conditioner User Manual
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IEEE 488.2 Common Commands
calibration factor has been stored in NOVRAM. Self test is terminated if a
failure is detected by tests 4, 5, or 6 with nominal calibration factors loaded.
7. Each channel contains a DAC that is used to trim the channel gain for each
attenuator setting and variable gain amplifier setting. This test verifies that
these DACs are functioning properly.
8. The cutoff frequency of each lowpass filter is controlled by a 5-bit tuning
word. The VX4780 verifies that each bit in the tuning word produces the
correct cutoff frequency. The cutoff frequency is checked indirectly by
measuring the group delay of the filter.
9. The AC coupling capacitors for the positive and negative inputs of each
channel are tested. This test also tests the 1 M input resistor of each
channel input by measuring the RC time constant of the network formed by
the AC coupling capacitor and the 1 M input resistor of each input.
10. The gain of the variable gain amplifier is checked at gains of 2, 5, 10, 20, 50,
and 100. This test is performed with nominal calibration factors, then
repeated with stored calibration factors. If this test passes with nominal
calibration factors and fails with stored calibration factors, this indicates that
an incorrect calibration factor has been stored in NOVRAM. Note that the
variable gain amplifier has already been tested at a gain of 1 in test 4.
The following is a description of the messages placed in the Error/Event queue
during self test. Each message contains one or more hexadecimal masks that
indicate the channel(s) that the message applies to. The least significant bit (bit
0) of the mask is set if the message applies to channel 1, bit 1 is set if the
message applies to channel 2, ..., bit 15 is set if the message applies to channel
16. For example a mask value of hexadecimal 8007 indicates that the message
applies to channels 1, 2, 3, and 16.
–330,“Self-test failed; self test a/d converter failure”
The VX4780 uses a 14 bit a/d converter to measure channel input and output
voltages in tests 2 through 10. If an a/d converter time-out occurs during any
of these tests, this error message is placed in the Error/Event queue and self
test is terminated.
–330,“Self-test failed; Novram checksum, Constant type/Channel mask: Gain/x,
Offset/x
One or more channels failed test number 1. The first hexadecimal mask
indicates which channel(s) have an incorrect gain calibration constant
checksum. The second hexadecimal mask indicates which channel(s) have an
incorrect offset calibration constant checksum.
–330,“Self-test failed; Offset trim dac(s), Channel mask: x”
3–38
VX4780 16-Channel Signal Conditioner User Manual
IEEE 488.2 Common Commands
One or more channels failed test number 2. The hexadecimal mask at the end
of this error message indicates which channel(s) failed.
–330, “Self-test failed; Input test voltage, Input/Channel mask: Neg/x, Pos/x
One of more channels failed test number 3. The first hexadecimal mask
indicates which channel(s) had a failure on the negative input. The second
hexadecimal mask indicates which channel(s) had a failure on the positive
input.
–330,“Self-test failed; Attenuator bypass with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
One or more channels failed test number 4 with nominal calibration factors
loaded. The first hexadecimal mask at the end of this error message indicates
which channel(s) failed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) failed the test of the positive
channel input.
–330,“Self-test failed; Attenuator bypass with stored cal, Input/Channel mask:
Neg/x, Pos/x”
One or more channels failed test number 4 with stored calibration factors
loaded. The first hexadecimal mask at the end of this error message indicates
which channel(s) failed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) failed the test of the positive
channel input.
–330,“Self-test failed; /10 Attenuator(s) with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
One or more channels failed test number 5 with nominal calibration factors
loaded. The first hexadecimal mask at the end of this error message indicates
which channel(s) failed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) failed the test of the positive
channel input.
–330,“Self-test failed; /10 Attenuator(s) with stored cal, Input/Channel mask:
Neg/x, Pos/x”
One or more channels failed test number 5 with stored calibration factors
loaded. The first hexadecimal mask at the end of this error message indicates
which channel(s) failed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) failed the test of the positive
channel input.
–330,“Self-test failed; /100 Attenuator(s) with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
One or more channels failed test number 6 with nominal calibration factors
loaded. The first hexadecimal mask at the end of this error message indicates
VX4780 16-Channel Signal Conditioner User Manual
3–39
IEEE 488.2 Common Commands
which channel(s) failed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) failed the test of the positive
channel input.
–330,“Self-test failed; /100 Attenuator(s) with stored cal, Input/Channel mask:
Neg/x, Pos/x”
One or more channels failed test number 6 with stored calibration factors
loaded. The first hexadecimal mask at the end of this error message indicates
which channel(s) failed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) failed the test of the positive
channel input.
–330,“Self-test failed; Gain trim dac(s) , Channel mask: x”
One or more channels failed test number 7. The hexadecimal mask at the end
of this error message indicates which channel(s) failed.
–330,“Self-test failed; Low pass filter(s), Tuning bit/Channel mask: 0/x, 1/x, 2/x,
3/x, 4/x”
One or more channels failed test number 8. The hexadecimal masks at the
end of this error message indicates which tuning bit(s) of which channel(s)
failed. The first mask indicates which channels(s) failed the test of least
significant cutoff frequency tuning bit. The last mask indicates which
channel(s) failed the test of the most significant cutoff frequency tuning bit.
–330,“Self-test failed; AC coupling capacitors, Input/Channel mask: Neg/x,
Pos/x”
One or more channels failed test number 9. The first hexadecimal mask
indicates which channels failed the test of the negative input ac coupling
capacitor. The second hexadecimal mask indicates which channels failed the
test of the positive input ac coupling capacitor.
–330,“Self-test failed; Variable gain amplifier(s) with nominal cal, Gain/Channel
mask: 2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
One or more channels failed test number 10 with nominal calibration factors
loaded. The six hexadecimal masks at the end of this error message
correspond to gains of 2, 5, 10, 20, 50, and 100. The first mask indicates
which channels failed at a gain of 2, the second indicates which channels
failed at a gain of 5, and so on.
–330,“Self-test failed; Variable gain amplifier(s) with stored cal, Gain/Channel
mask: 2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
3–40
One or more channels failed test number 10 with stored calibration factors
loaded. The six hexadecimal masks at the end of this error message
correspond to gains of 2, 5, 10, 20, 50, and 100. The first mask indicates
VX4780 16-Channel Signal Conditioner User Manual
IEEE 488.2 Common Commands
which channels failed at a gain of 2, the second indicates which channels
failed at a gain of 5, and so on.
10,“Test passed; Novram checksum, Constant type/Channel mask: Gain/x,
Offset/x
All channels tested passed test number 1. The first hexadecimal mask
indicates which channel(s) have a correct gain calibration constant checksum. The second hexadecimal mask indicates which channel(s) have a
correct offset calibration constant checksum.
10,“Test passed; Offset trim dac(s), Channel mask: x”
All channels tested passed test number 2. The hexadecimal mask at the end
of this message indicates which channels were tested.
10, “Test passed; Input test voltage, Input/Channel mask: Neg/x, Pos/x
All channels tested passed 3. The first hexadecimal mask indicates which
channel(s) passed the negative input test. The second hexadecimal mask
indicates which channel(s) passed the positive input test.
10,“Test passed; Attenuator bypass with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
All channels tested passed test number 4 with nominal calibration factors
loaded. The first hexadecimal mask at the end of this message indicates
which channel(s) passed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) passed the test of the positive
channel input.
10,“Test passed; Attenuator bypass with stored cal, Input/Channel mask: Neg/x,
Pos/x”
All channels tested passed test number 4 with stored calibration factors
loaded. The first hexadecimal mask at the end of this message indicates
which channel(s) passed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) passed the test of the positive
channel input.
10,“Test passed; /10 Attenuator(s) with nominal cal, Input/Channel mask: Neg/x,
Pos/x”
All channels tested passed test number 5 with nominal calibration factors
loaded. The first hexadecimal mask at the end of this message indicates
which channel(s) passed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) passed the test of the positive
channel input.
10,“Test passed; /10 Attenuator(s) with stored cal, Input/Channel mask: Neg/x,
Pos/x”
VX4780 16-Channel Signal Conditioner User Manual
3–41
IEEE 488.2 Common Commands
All channels tested passed test number 5 with stored calibration factors
loaded. The first hexadecimal mask at the end of this message indicates
which channel(s) passed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) passed the test of the positive
channel input.
10,“Test passed; /100 Attenuator(s) with nominal cal, Input/Channel mask:
Neg/x, Pos/x”
All channels tested passed test number 6 with nominal calibration factors
loaded. The first hexadecimal mask at the end of this message indicates
which channel(s) passed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) passed the test of the positive
channel input.
10,“Test passed; /100 Attenuator(s) with stored cal, Input/Channel mask: Neg/x,
Pos/x”
All channels tested passed test number 6 with stored calibration factors
loaded. The first hexadecimal mask at the end of this message indicates
which channel(s) passed the test of the negative channel input. The second
hexadecimal mask indicates which channel(s) passed the test of the positive
channel input.
10,“Test passed; Gain trim dac(s), Channel mask: x”
All channels tested passed test number 7. The hexadecimal mask at the end
of this message indicates which channels were tested.
10,“Test passed; Low pass filter(s), Tuning bit/Channel mask: 0/x, 1/x, 2/x, 3/x,
4/x”
All channels tested passed test number 8. The hexadecimal masks at the end
of this message indicate which channels were tested.
10,“Test passed; AC coupling capacitors, Input/Channel mask: Neg/x, Pos/x”
All channels tested passed test number 9. The first hexadecimal mask
indicates which channels passed the test of the negative input ac coupling
capacitor. The second hexadecimal mask indicates which channels passed the
test of the positive input AC coupling capacitor.
10,“Test passed; Variable gain amplifier with nominal cal, Channel mask: 2/x,
5/x, 10/x, 20/x, 50/x, 100/x”
All channels tested passed test number 10 with nominal calibration factors
loaded. The six hexadecimal masks at the end of this message correspond to
gains of 2, 5, 10, 20, 50, and 100. The first mask indicates which channels
passed at a gain of 2, the second indicates which channels passed at a gain of
5, and so on.
3–42
VX4780 16-Channel Signal Conditioner User Manual
*WAI
IEEE 488.2 Common Commands
10,“Test passed; Variable gain amplifier with stored cal, Gain/Channel mask:
2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
All channels tested passed test number 10 with stored calibration factors
loaded. The six hexadecimal masks at the end of this message correspond to
gains of 2, 5, 10, 20, 50, and 100. The first mask indicates which channels
passed at a gain of 2, the second indicates which channels passed at a gain of
5, and so on.
Wait to Continue. This command causes the module to wait until all pending
commands and queries are complete. All commands following *WAI are
suspended until the pending operations are complete.
VX4780 16-Channel Signal Conditioner User Manual
3–43
Status and Events
The Status and Event Reporting System reports asynchronous events and errors
that occur in the VX4780 16-Channel Signal Conditioner. This system consists
of four 8-bit registers and two queues that you access through the command
language. You can use these registers and queues to query the instrument status
and control the interrupts that report events.
In general, after an interrupt occurs, first conduct a serial poll, query the registers
to see why the interrupt occurred, and then send the SYSTem:ERRor? query to
see a descriptive error message.
This section describes the four registers and two queues of the Status and Event
Reporting system. For each register, you are given a description, a table
describing all of the bits, and an example of how to use the register.
The Status and Event Reporting process, synchronizing programming commands, and the system messages are also described in this section.
Status and Event Reporting System
Status Byte Register
The Status and Event Reporting system monitors and reports such events as an
error occurring or the availability of a response to a query. This system includes
descriptions of the following registers and queues:
H Status Byte Register
H Service Request Enable Register
H Standard Event Status Register
H Event Status Enable Register
H Output queue
H System Error and Event queue
The Status Byte Register, shown in Table 4–1, summarizes information from
other registers. Use a serial poll or a *STB? query to read the contents of the
Status Byte Register. The response is the sum of the decimal values for all bits
set. When you use a serial poll, bit 6 shows Request Service information. When
you use the *STB? query, bit 6, the Master Status Summary bit, indicates that
bits 5, 4, or 2 may be set.
VX4780 16-Channel Signal Conditioner User Manual
4–1
Status and Events
T able 4–1: The Status Byte Register
Decimal
Bit
0–1 – Not used.
2 4 Error/Event Queue Not Empty indicates that information is
3 – Not used.
4 16 Message Available shows that output is available in the Output
5 32 Event Status Bit indicates that one or more events have occurred
6 64 Request Service (obtained from a serial poll) shows that the
7 – Not used.
Value
Function
contained in the Error/Event queue and is waiting to be read.
queue.
and the corresponding bits in the Standard Event Status Register
have been set.
VX4780 has requested service from the GPIB controller.
Master Status Summary (obtained from *STB? query) summarizes
the Event Status bit, Message Available bits, and Error/Event
queue Not Empty bits in the Status Byte Register.
Service Request Enable
Register
A common example of using the Status Byte register is to enable the Message
Available bit. This is done by sending an *SRE 16 command to the VX4780
VXI Interface Module. If the *STB? query returns a value of 80, bit 4 (decimal
value of 16) and bit 6 (decimal value of 64) have been set (giving a decimal sum
of 80). Bit 4 indicates that a message is available in the output queue. Bit 6
indicates that a bit in the Status Byte register that has been enabled by setting the
corresponding bit in the Service Request Enable register (in this case bit 4) has
been set.
The Service Request Enable Register, shown in Table 4–2, controls which bits in
the Status Byte Register will generate a service request. Use the *SRE command
to set bits in the Service Request Enable Register. Use the *SRE? query to see
which bits in this register are enabled. The response from this query is the sum
of the decimal values for all bits set.
T able 4–2: The Service Request Enable Register
Decimal
Bit
0–1 – Not used.
2 4 Error/Event queue Bit indicates that a service request will be
Value
Function
generated when a message is placed in the Error/Event queue.
4–2
VX4780 16-Channel Signal Conditioner User Manual
Status and Events
T able 4–2: The Service Request Enable Register (Cont.)
Decimal
Bit Function
3 8 Not used.
4 16 Message Available Bit indicates that a service request will be
5 32 Event Status Bit indicates that events summarized in bit 5 of
6–7 – Not used.
Value
generated when a message is placed in the Output queue.
the Status Byte Register will generate a service request.
If, for example, the *SRE? query returns a value of 48, bits 4 and 5 are set in the
Service Request Enable Register. Any event that causes the Message Available
bit (bit 4) or Event Status bit (bit 5) to be set in the Status Byte Register now
generates an interrupt. If you want an interrupt to be generated only when the
Event Status bit (bit 5) is set, use the *SRE 32 command.
Standard Event Status
Register
The Standard Event Status Register, shown in Table 4–3, records many types of
events that can occur in the VX4780. Use the *ESR? query to read the contents
of this register. The response is the sum of the decimal values for all bits set.
Reading this register clears all bits so the register can accumulate information
about new events.
T able 4–3: The Standard Event Status Register
Decimal
Bit
0 1 Operation Complete shows that the operation is complete. This
1 – Not used.
2 4 Query Error shows that data in the Output queue was lost.
3 8 Device Dependent Error shows that an overflow condition
4 16 Execution Error shows that an error occurred while the VX4780
5 32 Command Error shows that an error occurred while the
Value
Function
bit is set when all pending operations complete following a
*OPC command.
exists in either the Error/Event Queue or the Output Queue.
This bit is also set if the VX4780 fails selftest. Table 4–7 on
pages 4–7 and 4–8 lists the device dependent error messages.
was executing a command or query. Table 4–6 on page 4–8
lists the execution error messages.
VX4780 was parsing a command or query. Table 4–5 on page
4–7 lists the command error messages.
VX4780 16-Channel Signal Conditioner User Manual
4–3
Status and Events
T able 4–3: The Standard Event Status Register (Cont.)
Decimal
Bit Function
6 – Not used.
7 128 Power On shows that the VX4780 was powered on.
Value
The following example assumes that all bits have been enabled using the Event
Status Enable Register (see the next section for information about this register).
If a *ESR? query returns a value of 128, bit 7 (decimal value of 128) is set
indicating that the instrument is in the initial power-on state.
Event Status Enable
Register
The Event Status Enable Register, shown in Table 4–4, controls which events are
summarized in the Event Status bit (bit 5) of the Status Byte Register. Use the
*ESE command to set bits in the Event Status Enable Register. Use the *ESE?
query to see what bits in the Event Status Enable Register are set. The response
from this query is the sum of the decimal values for all bits summarized in the
event status bit of the Status Byte Register.
T able 4–4: The Event Status Enable Register
Decimal
Bit
0 1 Set bit 5 of the Status Byte register when bit 1 (the Operation
1 2 Not used.
2 4 Set bit 5 of the Status Byte register when bit 2 (the Query Error
3 8 Not used.
4 16 Set bit 5 of the Status Byte register when bit 4 (the Execution
5 32 Set bit 5 of the Status Byte register when bit 5 (the Command
Value
Function
Complete bit) of the Standard Event Status register is set.
bit ) of the Standard Event Status register is set.
Error bit) of the Standard Event Status register is set.
Error bit) of the Standard Event Status register is set.
4–4
6 64 Not used.
7 128 Set bit 5 of the Status Byte register when bit 7 (the Power On
bit) of the Standard Event Status register is set.
If, for example, the *ESE? query returns a value of 255, all bits are set,
indicating that all events will set the event status bit (bit 5) of the Status Byte
Register.
VX4780 16-Channel Signal Conditioner User Manual
Status and Events
The Output Queue
The System Error and
Event Queue
The VX4780 stores query responses in the Output queue.
The VX4780 error and event messages are stored in the System Error and Event
queue. Use the SYSTem:ERRor? query to get the event number and a text
description of the event. Reading an event removes it from the queue. The Event
queue stores detailed information for up to 20 events; the events are stored in
first-in first-out order.
VX4780 16-Channel Signal Conditioner User Manual
4–5
Status and Events
Status and Event Reporting Process
Figure 4–1 shows how to use the Status and Event Reporting system. In the
explanation that follows, numbers in parentheses refer to the circled numbers in
Figure 4–1.
1
11
Standard Event Status
register
Read using *ESR?
Event Status Enable
register
Read using *ESE?
Write using *ESE
Status Byte
register
Read using
*STB?
Service Request Enable
register
Read using *SRE?
Write using *SRE
765 4 3 210
PowerOn— Command
Error
765 4 3 210
PowerOn— Command
Error
6
Request
7543210
Service
—
6
Master
Status
6
7543210
6
— Event
Status Bit
——
Status Bit
3
Event
Execution
Error
Execution
Error
Message
Available
Message
Available
Query
—
Error
2
Query
—
5
Error
4
queue Not
——
Empty
——
—
—
—
Operation
Complete
Operation
Complete
1
—
Event
Event
Event
Byte
Byte
Byte
Event
queue
Output
queue
Figure 4–1: Status and Event Reporting Process
When an event occurs the appropriate bit in the Standard Event Status Register is
set to one and the event is recorded in the Event queue (1). If the corresponding
bit in the Event Status Enable Register is also enabled (2), then the event status
bit in the Status Byte Register is set to one (3).
4–6
VX4780 16-Channel Signal Conditioner User Manual
Messages
Status and Events
When output is sent to the Output queue (for example, a response to a query), the
message available bit in the Status Byte Register is set to one (bit 4).
When a bit in the Status Byte Register is set to one and the corresponding bit in
the Service Request Enable Register is enabled (5), the Master Status Summary
bit in the Status Byte Register is set to one and a service request is generated (bit
6).
The VX4780 generates error messages in response to events caused by commands or queries. Each type of event sets a specific bit in the Standard Event
Status Register. Thus, each message is associated with a specific Standard Event
Status Register bit. In the message tables that follow, the associated Standard
Event Status Register bit is specified in the table title. Not shown in the tables
are secondary messages giving more detail about the cause of the error or the
meaning of the message. These secondary messages are shown for each
command and query in Syntax and Commands.
Table 4–5 shows the error messages generated by improper command syntax.
Check to see that the command is properly formatted and that it follows the rules
in Syntax and Commands.
T able 4–5: Command Error Messages
(Bit 5 in Standard Event Status Register)
Code Message
0 “No error”
–102 “Syntax error;Unexpected x detected while ...”
–108 “Parameter count exceeded for xxxx command”
–109 “Missing parameter for xxxx command”
–121 “Invalid character in number”
–123 “Exponent too large”
Table 4–6 lists the execution error messages that can occur during execution of a
command.
VX4780 16-Channel Signal Conditioner User Manual
4–7
Status and Events
T able 4–6: Execution Error Messages
(Bit 4 in Standard Event Status Register)
Code Message
–221 “Settings conflict; /100 attenuator setting conflict with upper range
filter cutoff frequency, Channel mask x”
–222 “Data out of range; Minimum cutoff frequency is 468 Hz”
–222 “Data out of range; Maximum cutoff frequency is 107 KHz”
–222 “Data out of range; Maximum gain is 100”
–222 “Data out of range; Minimum gain is 1”
–222 “Data out of range”
–222 “Data out of range; Illegal channel number: x”
–224 “Illegal parameter value; Allowed gains are 1 and 10”
–224 “Illegal parameter value; Allowed gains are 1,2,5 and 10”
–224 “Illegal parameter value; Allowed gains are 1 to 100 in 1/2/5 steps”
–224 “Illegal parameter value; Allowed attenuations are 10 and 100”
Table 4–7 lists the device dependent error messages that can occur during
VX4780 operation. Number –330 error messages are placed in the Error/Event
queue to indicate which channels failed self test. See the description of the
*TST? query for more information on these error messages.
T able 4–7: Device Dependent Error Messages
(Bit 3 in Standard Event Status Register)
Code Message
–330 “Self-test failed; self test ADC failure”
–300 “Self-test failed; Novram checksum, Constant type/Channel mask:
Gain/x, Offset/x
–330 “Self-test failed; Offset trim dac(s), Channel mask: x”
–330 “Self-test failed; Input test voltage, Input/Channel mask: Neg/x,
Pos/x
–330 “Self-test failed; Attenuator bypass with nominal cal, Input/Channel
mask: Neg/x, Pos/x”
–330 “Self-test failed; Attenuator bypass with stored cal, Input/Channel
mask: Neg/x, Pos/x”
–330 “Self-test failed; /10 Attenuator(s) with nominal cal, Input/Channel
mask: Neg/x, Pos/x”
–330 “Self-test failed; /10 Attenuator(s) with stored cal, Input/Channel
mask: Neg/x, Pos/x”
4–8
VX4780 16-Channel Signal Conditioner User Manual
Status and Events
T able 4–7: Device Dependent Error Messages
(Bit 3 in Standard Event Status Register) (Cont.)
Code Message
–330 “Self-test failed; /100 Attenuator(s) with nominal cal, Input/Channel
mask: Neg/x, Pos/x”
–330 “Self-test failed; /100 Attenuator(s) with stored cal, Input/Channel
mask: Neg/x, Pos/x”
–330 “Self-test failed; Gain trim dac(s) , Channel mask: x”
–330 “Self-test failed; Low pass filter(s), Tuning bit/Channel mask: 0/x,
1/x, 2/x, 3/x, 4/x
–330 “Self-test failed; AC coupling capacitors, Channel masks: x x”
–330 “Self-test failed; Variable gain amplifier(s) with nominal cal,
Gain/Channel mask: 2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
–330 “Self-test failed; Variable gain amplifier(s) with stored cal,
Gain/Channel mask: 2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
–350 “Queue overflow; Error/event queue”
–350 “Queue overflow; Output queue”
Table 4–8 lists the user event messages that can occur during VX4780 operation.
Number 10 messages are placed in the Error/Event queue during self test to
indicate which channels passed self test. See the description of the *TST? query
for more information on these error messages.
T able 4–8: User Event Messages
Code Message
10 “Test passed; Novram checksum, Constant type/Channel mask:
Gain/x, Offset/x
10 “Test passed; Offset trim dac(s), Channel mask: x”
10 “Test passed; Input test voltage, Input/Channel mask: Neg/x, Pos/x
10 “Test passed; Attenuator bypass with nominal cal, Input/Channel
mask: Neg/x, Pos/x”
10 “Test passed; Attenuator bypass with stored cal, Input/Channel
mask: Neg/x, Pos/x”
10 “Test passed; /10 Attenuator(s) with nominal cal, Input/Channel
mask: Neg/x, Pos/x”
10 “Test passed; /10 Attenuator(s) with stored cal, Input/Channel mask:
Neg/x, Pos/x”
10 “Test passed; /100 Attenuator(s) with nominal cal, Input/Channel
mask: Neg/x, Pos/x”
VX4780 16-Channel Signal Conditioner User Manual
4–9
Status and Events
T able 4–8: User Event Messages (Cont.)
Code Message
10 “Test passed; /100 Attenuator(s) with stored cal, Input/Channel
mask: Neg/x, Pos/x”
10 “Test passed; Gain trim dac(s), Channel mask: x”
10 “Test passed; Low pass filter(s), Tuning bit/Channel mask: 0/x, 1/x,
2/x, 3/x, 4/x”
10 “Test passed; AC coupling capacitors, Input/Channel mask: Neg/x,
Pos/x”
10 “Test passed; Variable gain amplifier with nominal cal, Channel
mask: 2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
10 “Test passed; Variable gain amplifier with stored cal, Gain/Channel
mask: 2/x, 5/x, 10/x, 20/x, 50/x, 100/x”
4–10
VX4780 16-Channel Signal Conditioner User Manual
Appendix A: Specifications
re
T able A–1: VXI Instrument Characteristics
Characteristics Description
VXI General Characteristics The instrument provides a VXI interface that complies with Revision 1.4.
The VXI interface is defined by the VXI Consortium, Inc.
Interface Type Message Based (1.4)
Protocols Word Serial (WSP)
T able A–2: Environmental/Reliability Characteristics
Characteristics
Temperatu
Humidity Relative Humidity:
Altitude (1) Operating: 6,000 ft. altitude.
Altitude (2) Meets or exceeds MIL-T -28800E for Type III, (operating to 10,000 ft., nonoperating to
Description
Operating: Meets or exceeds MIL-T-28800E for Type III, 0 to 50_C external ambient,
when operated in a mainframe providing Class 3 equipment.
Nonoperating: –40_C to +71_C
Airflow of at least 4.432 liters/sec at 0.09 mm H2O air pressure, –10_C/55_C for
10_C (or less) temperature rise of internal air, as measured at the cooling air exit
points, and with no heat transfer either to or from any adjacent VXI modules.
Nonoper: Up to 95%, at up to 50_C.
Operating: Up to 95% at up to 30_C, and up to 45%, at up to 50_C.
15,000 ft.).
T able A–3: VX4780–Specific Characteristics
Characteristics Description
Number of signal conditioning channels 16
Number of VXI slots 1
Input Configuration Differential inputs
Differential Input Impedance 2 MW +0.2% –0.0%
Input AC coupling capacitors 18 nF ±1%
Input capacitance to ground 75 pF typical with input attenuator bypassed.
55 pF typical with input attenuator inserted.
VX4780 16-Channel Signal Conditioner User Manual
A–1
Appendix A: Specifications
T able A–3: VX4780–Specific Characteristics (Cont.)
Characteristics Description
Channel to Channel crosstalk referenced to
input
Input Coupling AC, DC, or ground. Command selectable.
Maximum Input Voltage 150 V AC
Input Common Mode Range Input Attenuator Input Common
Input Slew Rate
Output Configuration Differential outputs
Differential Output Impedance 50 W 5 W
Differential Load Impedance The load connected to the output of each channel must be greater than or equal to
Gain Accuracy Overall channel gain must be accurate to within ± 0.5% for all gain/attenuation settings
Output Coupling DC
Output Short Circuit Protection Outputs are short circuit protected.
Low Pass Filter Response Each signal conditioning channel contains a 4th order low pass filter with a Bessel
Low Pass Filter Attenuation at Programmed
Cutoff Frequency
<–80 dB at 20 kHz.
Crosstalk decreases by 6 dB/octave as frequency is decreased. Crosstalk increases by
6 dB/octave as frequency is increased.
±212 V peak in CA T I environment.
RMS,
Gain volt/volt Mode Range
1 ±10V
0.1 ±100V
0.01 ±200V
Gain Setting Maximum Input
(V/V) Slew Rate (V/
1 10.0
2 5.0
5 2.0
10 1.0
20 0.5
50 0.2
100 0.1
The slew rates listed assume that the input attenuator is bypassed. Multiply the slew
rates by 10 if the /10 attenuator is inserted. Multiply the slew rates by 100 if the /100
attenuator is inserted.
600 W.
listed below, with a 200 k W load across the channel differential outputs.
Gain = 1,2,5,10,20,50,100 with attenuator bypassed
Gain = 10 with /10 attenuator inserted
Gain = 100 with /100 attenuator inserted
response.
Low pass filter attenuation should be between –3.0 dB ±0.5 dB (±0.2 dB, typical) at the
programmed cutoff frequency.
msec)
A–2
VX4780 16-Channel Signal Conditioner User Manual
Appendix A: Specifications
T able A–3: VX4780–Specific Characteristics (Cont.)
Characteristics Description
Common Mode Rejection Ratio Common Mode Rejection Ratio at 60 Hz
Input Attenuator Gain
CMRR Coupling Setting Setting
≥90dB DC bypassed gain ≥ 10
≥70dB DC bypassed gain ≤ 5
≥55dB DC inserted 1 ≤ gain ≤100
≥55dB AC bypassed 1 ≤ gain ≤100
≥50dB AC inserted 1 ≤ gain ≤100
Signal to Noise and Distortion Ratio (SINAD) Minimum / (Typical) SINAD in dB vs. Gain and Signal Frequency
Signal frequency (Hz)
Gain (V/V) 1k 10k 20k 100k
1* 80/(96) 70/(85) 65/(80) 60/(75)
1** 80/(96) 75/(90) 70/(85) 65/(80)
1*** 80/(90) n/a n/a n/a
2* 80/(96) 70/(85) 65/(80) 55/(70)
5* 80/(93) 70/(85) 65/(80) 45/(60)
10* 80/(95) 70/(85) 65/(80) 60/(75)
20* 80/(93) 70/(85) 65/(80) 55/(70)
50* 70/(88) 65/(80) 60/(75) 45/(60)
100* 65/(80) 60/(75) 55/(70) 45/(60)
* VX4780 input attenuator bypassed
** VX4780 /10 input attenuator inserted, gain set to 10
*** VX4780 /100 input attenuator inserted, gain set to 100
SINAD measured with the following lowpass filter settings
Signal Frequency (Hz) Lowpass Filter Cutoff Frequency
1k 1.872k
10k 21.4k
20k 42.8k
100k 107k
DC Offset at Output with Inputs Grounded DC Offset at channel output should be 0 V 5 millivolts
Isolation Relays Inputs and outputs are switched through isolation relays. These relays are opened
during self test and when power is removed from the module.
Input Connectors Two connectors are used as input connectors. The Tektronix part number for this
connector is 131–3395–00. The Amp Inc. part number is 747842–4.
Output Connectors Two connectors are used as input connectors. The Tektronix part number for this
connector is 131–5713–00. The Amp Inc. part number is 748481–5.
VX4780 16-Channel Signal Conditioner User Manual
A–3
Appendix A: Specifications
EC Declaration of Conformity Meets intent of Directive 89/336/EEC for Electromagnetic Compatibility and Low Voltage Directive
73/23/ECC for Product Safety. Compliance was demonstrated to the following specifications as
listed in the Official Journal of the European Communities:
EMC Directive 89/336/EEC:
EN 55011 Class A Radiated and Conducted Emissions
EN 50081-1 Emissions:
EN 60555-2 AC Power Line Harmonic Emissions
EN 50082-1 Immunity:
IEC 801-2 Electrostatic Discharge Immunity
IEC 801-3 RF Electromagnetic Field Immunity
IEC 801-4 Electrical Fast Transient/Burst Immunity
IEC 801-5 Power Line Surge Immunity
Low Voltage Directive 73/23/EEC:
EN 61010-1 Safety requirements for electrical equipment for measurement,
control and laboratory use
To ensure compliance with EMC requirements this module must be installed in a mainframe which
has backplane shields installed which comply with Rule B.7.45 of the VXIbus Specification. Only
high quality shielded cables having a reliable, continuous outer shield (braid and foil) which has low
impedance connections to shielded connector housings at both ends should be connected to this
product.
EMC Compliance Meets the intent of Directive 89/336/EEC for Electromagnetic Compatibility when it is used with the
product(s) stated in the specifications table. Refer to the EMC specification published for the stated
products. May not meet the intent of the Directive if used with other products.
Certifications Underwriters Laboratories Listed to CAN/CSA–C22.2 No. 1010.1–92, Electrical Equipment for
Measurement, Control and Laboratory Use.
Underwriters Laboratories Listed to Standard UL3111-1 for Electrical Measuring and Test
Equipment.
Safety Certification of Plug-in or
VXI Modules
For modules (plug-in or VXI) that are safety certified by Underwriters Laboratories, UL Listing
applies only when the module is installed in a UL Listed product.
For modules (plug-in or VXI) that have cUL or CSA approval, the approval applies only when the
module is installed in a cUL or CSA approved product.
Overvoltage Category Category: Examples of Products in this Category:
CA T III Distribution-level mains, fixed installation
Local-level mains, appliances, portable equipment
Signal levels in special equipment or parts of equipment, telecommu-
nications, electronics
VX4780 16-Channel Signal Conditioner User Manual
Pollution Degree 2
A–4
CA T II
CA T I
Do not operate in environments where conductive pollutants may be present.
Appendix B: Input/Output Connections
Pinout for VX4780 input connectors:
channel +input pin –input pin
1,9 1 14
2,10 15 3
3,11 4 17
4,12 18 6
5,13 7 20
6,14 21 9
7,15 10 23
8,16 24 12
ground pins 2, 5, 8, 11, 16, 19, 22, 25
Pin 13 is not used
Pinout for VX4780 output connectors:
channel +input pin –input pin
1,9 9 18
2,10 8 17
3,11 7 16
4,12 6 15
5,13 5 14
6,14 4 13
7,15 3 12
8,16 2 11
ground pins 19, 20, 21, 22, 23, 24, 25, 26
Pins 1 and 10 are not used
VX4780 16-Channel Signal Conditioner User Manual
B–1
Appendix C: Examples
These examples demonstrate how some of the programmable features of the
VX4780 are used. It is assumed the module has completed its power-on self test.
For information on specific commands or syntax, please review the Syntax and
Commands section.
Example 1
In this example, self test is performed on channels 1 through 8. The response to
the *tst? query is an ASCII “0” indicating that all channels passed all elements of
the self test. SYSTem:ERRor? queries are issued in order to read the results of
each element of self test. These messages are placed in the Error/Event queue at
the end of each test.
Note that all channel masks are set to hexadecimal 00FF. The lower eight bits of
the channel masks are set indicating that the messages apply to channels 1
through 8. If after reading back a “0” following the *TST? query, the user does
not wish to read the results of each element of the self test, a *CLS command
can be sent to the module. This clears the Error/Event queue containing the error
messages, but does not change the settings of the module.
Command Response
*tst? (@1:8) 0
system:error? “Test passed; Novram checksum, Constant type/Channel
mask: Gain/00FF , Offset/00FF”
system:error? “Test passed; Offset trim dac(s), Channel mask: 00FF”
system:error? “Test passed; Input test voltage, Input/Channel mask:
Neg/00FF, Pos/00FF”
system:error? “Test passed; Attenuator bypass with nominal cal, Input/Chan-
nel mask: Neg/00FF, Pos/00FF”
system:error? “Test passed; /10 Attenuator(s) with nominal cal, Input/Channel
mask: Neg/00FF , Pos/00FF”
system:error? “Test passed; /100 Attenuator(s) with nominal cal, Input/Chan-
nel mask: Neg/00FF, Pos/00FF”
system:error? “Test passed; Attenuator bypass with stored cal, Input/Channel
mask: Neg/00FF , Pos/00FF”
system:error? “Test passed; /10 Attenuator(s) with stored cal, Input/Channel
mask: Neg/00FF , Pos/00FF”
system:error? “Test passed; /100 Attenuator(s) with stored cal, Input/Channel
mask: Neg/00FF , Pos/00FF”
VX4780 16-Channel Signal Conditioner User Manual
C–1
Appendix C: Examples
Example 2
Command Response
system:error? “Test passed; Gain trim dac(s), Channel mask: 00FF”
system:error? “Test passed; Low pass filter(s), Tuning bit/Channel mask:
0/00FF, 1/00FF, 2/00FF , 3/00FF, 4/00FF”
system:error? “Test passed; AC coupling capacitors, Input/Channel mask:
Neg/00FF, Pos/00FF”
system:error? “Test passed; Variable gain amplifier with nominal cal,
Gain/Channel mask: 2/00FF, 5/00FF, 10/00FF, 20/00FF,
50/00FF, 100/00FF”
system:error? “Test passed; Variable gain amplifier with stored cal,
Gain/Channel mask: 2/00FF, 5/00FF, 10/00FF, 20/00FF,
50/00FF, 100/00FF”
system:error? 0, “No error”
In this example, all channels of the VX4780 are set to the following configuration:
Input isolation relay: Closed
Input coupling: DC
Input attenuator: Bypassed
Gain: 1V/V
Lowpass filter cutoff frequency: 20 kHz
Output isolation relays: Closed
Command Response
input:state on,(@1:16) no response
input:coupling dc,(@1:16) no response
input:Att:state off,(@1:16) no response
input:gain 1,(@1:16) no response
input:filter:lpass:Freq
20khz,(@1:16)
no response
C–2
output:state on,(@1:16) no response
system:Error? 0,“No error”
VX4780 16-Channel Signal Conditioner User Manual
Example 3
Appendix C: Examples
In this example, the VX4780 is used to generate a 7.13 kHz sine waveform at the
output of each channel for use as a test signal into the digitizer connected to
these outputs. This is accomplished by setting the lowpass filter cutoff frequency
to 7.13 kHz, then using the self test variable voltage source to apply a 7.13 kHz
5 V
square waveform to all channel inputs. The lowpass filters attenuate the
p-p
harmonics of the square waveform, creating a sine waveform at the channel
outputs. The overall channel gain is set to 2 V/V for each channel. The overall
channel gain is equal to the channel gain divided by the channel attenuation.
Note that it is necessary to send a VXI Clear command after the DIAGnostic:SQRwave command before the VX4780 will accept any additional commands.
Command Response
input:state off,(@1:16) no response
input:coupling ac,(@1:16) no response
input:att (@1:16) no response
input:Att:State on,(@1:16) no response
input:gain 20,(@1:16) no response
input:filter:lpass:Freq
7.13khz,(@1:16)
input:filter:lpass:Freq?
(@1:16)
output:State on,(@1:16) no response
diag:sqr 30 no response
no response
7133, 7133, 7133, 7133, 7133, 7133, 7133, 7133, 7133, 7133,
7133, 7133, 7133, 7133, 7133, 7133
VX4780 16-Channel Signal Conditioner User Manual
C–3
Appendix D: Diagnostics
The following commands are intended for calibration and for diagnosing
problems on the module and should not be used for any other purpose. An
exception is the “DIAGnostic:SQRwave” command, which can be used to
generate a test source waveform at the module output.
DIAGnostic:AD? <channel_list>,
DIAGnostic:CAL <caladr>,<caldata>,
DIAGnostic:CAL? <caladr>,
DIAGnostic:DC <input_voltage>,
DIAGnostic:GAIN <gaindac>,<channel_list>,
DIAGnostic:IAgain <iagain>,<channel_list>,
DIAGnostic:INPut:FILTer:LPASS <channel_list>
DIAGnostic:OFFSet <msoffset>,<lsoffset>,<channel_list>,
DIAGnostic:SQRwave <loopcount>,
DIAGnostic:STgain <stgain>,<channel_list>
NOTE. When the “DIAGostic:OFFSet” command is sent to the VX4780 and the
VXI end bit is asserted on the closing parenthesis character of the
<Channel_list> argument, the VX4780 ignores the command. A white space
character (with the VXI end bit asserted) or a line feed character (with or
without the VXI end bit asserted) must be sent after the closing paren of the
channel list in order for the VX4780 to parse and act on the command.
VX4780 16-Channel Signal Conditioner User Manual
D–1
Appendix D: Diagnostics
DIAGnostic:AD
Command Syntax
*RST Value
Related Commands
Description
Examples
DIAGnostic
:AD? <channel_list>
N/A
N/A
After an OUTPut:STATe off, <channel_list> command has been issued, the
specified channels are disconnected from the output connector and connected to
the input of an analog mux. The output of this mux is connected to the input of
the module’s self test analog-to-digital converter (ADC). The DIAGnostic:AD?
command routes the first channel specified in the channel list to the input of the
self test ADC, triggers the ADC, and returns the converted data in hexadecimal
format.
Full input range of the self test ADC is +3V to -3V which results in returned
hexadecimal values of 1fff to E000.
Command Response
diag:ad? (@1) 1AA5
DIAGnostic:CAL
Command Syntax
Query Syntax
*RST Value
D–2
In the above example the voltage at the ADC input is:
3V * 1AA5/1FFF = 3V * 6821.0/8191 = 2.5 volts
DIAGnostic
:CAL <caladr>,<caldata>
DIAGnostic:CAL? <caladr>
N/A
VX4780 16-Channel Signal Conditioner User Manual
Appendix D: Diagnostics
Related Commands
Description
N/A
This command writes data to NOVRAM. <caladr> is a value from 0 to 1023
equal to the NOVRAM address to write to. <caldata> is a value from 0 to 65535
to write to the specified NOVRAM location.
Gain and offset correction calibration factors for each channel are stored in
NOVRAM. The format for the gain calibration factors is listed in the following
table.
This command is used during factory calibration of the VX4780 Module. It is
described here for reference only and it is not recommended for use by the
customer.
The base address for the gain calibration factors for a channel is given by the
equation: (channel – 1) * 12.
NOVRAM address Calibration Factor Response
base address + 0 Gain trim DAC calibration factor. This factor represents the
gain change produced when the contents of the gain trim DAC
is changed by 1 count. The units of this factor are ppm*100 /
DAC count. The nominal value for this factor is 1689. This
indicates that a change of 1 DAC count produces a gain
change of 16.89 ppm. The values written to the gain trim DAC
range from 0 to 4095. As this value is increased, the channel
gain decreases.
base address + 1 Gain error in ppm when the channel gain is set to 1 and the
input attenuator is bypassed. For example, a value of 5500
indicates that when the nominal value of 2048 is written to the
gain trim DAC, the gain is 5500 ppm (0.55%) too high. Signed
integer format.
base address + 2 Gain error in ppm when the channel gain is set to 2 relative to
the gain error when the gain is set to 1. Signed integer format.
For example if the gain error with the gain set to 1 is 5500 ppm
and the gain error with the gain set to 5 is 6000 ppm, a value of
500 ppm will be stored in this location.
base address + 3 Gain error in ppm when the channel gain is set to 5 relative to
the gain error when the gain is set to 1. Signed integer format.
base address + 4 Gain error in ppm when the channel gain is set to 10 relative to
the gain error when the gain is set to 1. Signed integer format.
base address + 5 Gain error in ppm when the channel gain is set to 20 relative to
the gain error when the gain is set to 1. Signed integer format.
base address + 6 Gain error in ppm when the channel gain is set to 50 relative to
the gain error when the gain is set to 1. Signed integer format.
VX4780 16-Channel Signal Conditioner User Manual
D–3
Appendix D: Diagnostics
NOVRAM address Calibration Factor Response
base address + 7 Gain error in ppm when the channel gain is set to 100 relative
to the gain error when the gain is set to 1. Signed integer
format.
base address + 8 Gain error in ppm when the input attenuator is enabled and set
to divide the input signal by 10, relative to the gain error when
the attenuator is bypassed. Signed integer format.
For example, with the gain of the variable gain amplifier set to
1, if the gain error with the attenuator bypassed is 5500 ppm
and the gain error with the attenuator enabled is 6000 ppm, a
value of 500 will be stored in this location.
base address + 9 Gain error in ppm when the input attenuator is enabled and set
to divide the input signal by 100, relative to the gain error when
the attenuator is bypassed. Signed integer format.
For example, with the gain of the variable gain amplifier set to
1, if the gain error with the attenuator bypassed is 5500 ppm
and the gain error with the attenuator enabled is 6000 ppm, a
value of 500 will be stored in this location.
base address + 10 Reserved. Set to 0.
base address + 11 Checksum of constants stored in locations from base address
to base address + 11.
The format for the DC offset calibration factors is listed in the following table.
The base address for the gain calibration factors for a channel is given by the
equation: 192 + ( channel – 1 ) * 12.
NOVRAM address Calibration Factor Response
base address + 0 Offset trim DAC calibration factor. This factor represents the
full scale adjust range of the offset trim DAC. It is stored as an
unsigned integer in units of volts * 100000. The nominal value
for this constant is 39500. This indicates that the full scale
adjust range of the offset trim DAC is ±0.39500 volts.
base address + 1 Offset error at a gain setting of 1 with the channel inputs
shorted to ground. Stored as a signed integer in units of volts *
100000. For example, if the channel gain is set to 1 with an
INPUT:GAIN 1,(@channel_number> command and the offset
trim DAC is programmed to output 0 volts with a DIAG:OFF-
SET 0,128,(@channel_number) command and a voltage of 5.7
millivolts DC is measured at the output, a value of 570 will be
stored in this location when the module is calibrated.
D–4
base address + 2 Offset error at a gain setting of 2 with the channel inputs
shorted to ground. Stored as a signed integer in units of volts *
100000.
VX4780 16-Channel Signal Conditioner User Manual
Appendix D: Diagnostics
NOVRAM address Calibration Factor Response
base address + 3 Offset error at a gain setting of 5 with the channel inputs
shorted to ground. Stored as a signed integer in units of volts *
100000.
base address + 4 Offset error at a gain setting of 10 with the channel inputs
shorted to ground. Stored as a signed integer in units of volts *
100000.
base address + 5 Offset error at a gain setting of 20 with the channel inputs
shorted to ground. Stored as a signed integer in units of volts *
100000.
base address + 6 Offset error at a gain setting of 50 with the channel inputs
shorted to ground. Stored as a signed integer in units of volts *
100000.
base address + 7 Offset error at a gain setting of 100 with the channel inputs
shorted to ground. Stored as a signed integer in units of volts *
100000.
base address + 8 to base
address + 10
Reserved. Set to 0
DIAGnostic:DC
Command Syntax
*RST Value
Related Commands
Description
base address + 11 Checksum of constants stored in locations from base address
to base address + 11.
DIAGnostic:DC <input_voltage>
The voltage applied to the inputs of all channels is set to 0 V.
INput:STATe
This command applies a DC voltage to the inputs of all channels that have
their input isolation relays set to the open position. The voltage applied can
be set to +2.5 V, 0 V, or –2.5 V. If a positive value is specified for
<input_voltage>, the applied voltage is set to +2.5 V. If a negative value is
specified, the applied voltage is set to –2.5 V. If a value of 0.0 is specified, the
applied voltage is set to 0.0 V.
VX4780 16-Channel Signal Conditioner User Manual
D–5
Appendix D: Diagnostics
Examples
Command Response
input:state off, (@1:8) Open the input isolation relays of channels 1 through 8.
input:state on, (@9:16) Close the input isolation relays of channels 9 through 16.
diag:dc 2.5 Apply +2.5 volts to the inputs of channels 1 through 8. This
voltage is not applied to the inputs of channels 9 through 16
because the input isolation relays of these channels are in the
closed position.
diag:dc 0.0 Apply 0.0 volts to the inputs of channels 1 through 8. This
voltage is not applied to the inputs of channels 9 through 16
because the input isolation relays of these channels are in the
closed position.
diag:dc –2.5 Apply –2.5 volts to the inputs of channels 1 through 8. This
voltage is not applied to the inputs of channels 9 through 16
because the input isolation relays of these channels are in the
closed position.
DIAGnostic:GAIN
Command Syntax
*RST Value
Related Commands
Description
DIAGnostic:GAIN <gaindac>,<channel_list>
N/A
N/A
This command loads data into the gain trim DACs of the channel(s) specified in
the <channel_list>. <gaindac> is a decimal number between 0 and 4095. The
nominal value for <gaindac> is 2048.
The gain of the channel is given by the equation:
Gt = G ( 1 + ( ( 2048 – <gaindac> ) * 16.89/1000000 ) )
where G is the channel gain when <gaindac> = 2048.
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VX4780 16-Channel Signal Conditioner User Manual
Examples
DIAGnostic:IAgain
Appendix D: Diagnostics
Command Response
diag:gain 2048,(@1) Load the gain trim DAC of channel 1 with 2048, the nominal
value for the gain trim DAC
diag:cal? 0 1689
Read the gain trim in parts per 10000 per dac count for channel
1.
diag:gain 2049,(@1) Decrease the gain of channel 1 by–16.89 ppm.
(2048 -–2049) *16.89ppm = -16.89ppm
Command Syntax
*RST Value
Related Commands
Description
Examples
DIAGnostic
:IAgain <iagain>,<channel_list>
N/A
N/A
Each channel of the VX4780 contains a variable gain amplifier. This amplifier
consists of an instrumentation amplifier with programmable gains of 1 or 10
followed by an amplifier with programmable gains of 1, 2, 5, or 10. This
command sets the gain of the instrumentation amplifier of the specified channels
to either 1 or 10. It does not change the gain of the amplifier that follows the
instrumentation amplifier.
Command Response
diag:iagain 1,(@10) Set the gain of the instrumentation amplifier of channel 10 to 1.
diag:iagain 10,(@11) Set the gain of the instrumentation amplifier of channel 11 to
10.
DIAGnostic:INPut:FILTer:LPASS
Command Syntax
*RST Value
VX4780 16-Channel Signal Conditioner User Manual
DIAGnostic:INPut:FILTer:LPASS <channel_list>
N/A
D–7
Appendix D: Diagnostics
Limits
Related Commands
Description
Examples
DIAGnostic:OFFset
Command Syntax
N/A
N/A
This command opens the analog switches in the lowpass filter portion of the
channels specified in the <channel_list>. You can then use an ohmmeter to
measure the resistors that determine the filter cutoff frequency to check for
correct component values.
Command Response
diag:inp:filt:lpas (@9) Open the analog switches used to set the cutoff frequency of
the lowpass filter of channel 9.
DIAGnostic:OFFSet <msoffset>,<lsoffset>,<channel_list>
*RST Value
Limits
Related Commands
Description
N/A
N/A
N/A
This command loads data into the offset trim DACs of the channels specified in
the <channel_list>. <msoffset> is an ASCII decimal number from 0 to 128 that
is loaded into the ms offset DAC. <lsoffset> is an ASCII decimal number
between 0 and 255 that is loaded into the ls offset DAC. The resulting offset at
the output of the channel(s) specified is given by the equation:
Vo = [k * (128 – <msoffset>) / 128 * (128 – <lsoffset>) / 128] + m
where k is equal to 0.00001 multiplied by the contents of NOVRAM address
equal to:
192 + ((channel –1)*12 )
and m is equal to the DC offset when <msoffset> and <lsoffset> are set to 128.
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VX4780 16-Channel Signal Conditioner User Manual
Examples
DIAGnostic:SQRwave
Appendix D: Diagnostics
Command Response
diag:offset 128,128,(@1:6) Set the DC correction introduced by the offset trim DACs of
channels 1 through 16 to 0 V .
Command Syntax
*RST Value
Limits
Related Commands
Description
Examples
DIAGnostic:SQRwave <loopcount>
N/A
N/A
N/A
This command generates a 5 V
have their input isolation relays set to the open position. The frequency of the
square wave is controlled by the <loopcount> parameter. <loopcount> must be
between 0 and 65535. A VXI CLEAR command must be sent to the module
after this command is issued before it will accept new commands.
The period of the squarewave in microseconds is given by the equation:P =
10.4 + (4.4* <loopcount>)
Command Response
diag:sqr 225 Apply a 5 V
square wave at the input of all channels that
p-p
1 kHz square wave to the inputs of all channels
that have their input isolation relays in the open position. Note
that a loopcount of 225 is arrived at by solving the above equation given a waveform period of 1000 sec.
225 = (1000 - 10.4) / 4.4
p-p
DIAGnostic:STgain
Command Syntax
*RST Value
VX4780 16-Channel Signal Conditioner User Manual
DIAGnostic:STgain <stgain>,<channel_list>
N/A
D–9
Appendix D: Diagnostics
Limits
Related Commands
Description
Examples
N/A
N/A
Each channel of the VX4780 contains a variable gain amplifier. This amplifier
consists of an instrumentation amplifier with programmable gains of 1 or 10
followed by an amplifier with programmable gains of 1, 2, 5, or 10. This
command sets the gain of the amplifier that follows the instrumentation amplifier
to 1, 2, 5, or 10. This command does not change the gain of the instrumentation
amplifier.
Command Response
diag:stgain 2,(@10) Set the gain of the amplifier that follows the instrumentation
amplifier of channel 10 to 2.
diag:stgain 5,(@11) Set the gain of the amplifier that follows the instrumentation
amplifier of channel 11 to 5.
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VX4780 16-Channel Signal Conditioner User Manual
Appendix E: User Service
This appendix contains service-related information for the VX4780 that covers
the following topics:
H Performance Verification
H Preventive maintenance
H Troubleshooting
Performance Verification
You may use the Operational Check procedure listed in Getting Started to verify
that the module is operating correctly. The instrument has been fully tested and
calibrated before leaving the factory.
If the self test or diagnostic commands indicate a failure, contact your Tektronix
field office or representative for assistance.
Preventive Maintenance
Troubleshooting
You should perform inspection and cleaning as preventive maintenance.
Preventive maintenance, when done regularly, may prevent malfunction and
enhance reliability. Inspect and clean the instrument as often as conditions
require by following these steps:
1. Turn off power and remove the VX4780 from the VXIbus mainframe.
2. Remove loose dust on the outside of the instrument with a lint-free cloth.
3. Remove any remaining dirt with a lint-free cloth dampened with water or a
75% isopropyl alcohol solution. Do not use abrasive cleaners.
If you suspect a malfunction, first double check connections to and from the
instrument. If the trouble persists, perform the Functional Check.
If the self test indicates a failure, contact your Tektronix field office or representative for assistance.
VX4780 16-Channel Signal Conditioner User Manual
E–1
Appendix F: Replaceable Parts List
This section contains a list of the replaceable modules for the <VX4780>. Use
this list to identify and order replacement parts.
Parts Ordering Information
Replacement parts are available through your local Tektronix field office or
representative.
Changes to Tektronix products are sometimes made to accommodate improved
components as they become available and to give you the benefit of the latest
improvements. Therefore, when ordering parts, it is important to include the
following information in your order.
H Part number
H Instrument type or model number
H Instrument serial number
H Instrument modification number, if applicable
Module Servicing
If you order a part that has been replaced with a different or improved part, your
local Tektronix field office or representative will contact you concerning any
change in part number.
Change information, if any, is located at the rear of this manual.
Modules can be serviced by selecting one of the following three options. Contact
your local Tektronix service center or representative for repair assistance.
Module Exchange. In some cases you may exchange your module for a remanufactured module. These modules cost significantly less than new modules and
meet the same factory specifications. For more information about the module
exchange program, call 1-800-TEK-WIDE, extension 6630.
Module Repair and Return. You may ship your module to us for repair, after which
we will return it to you.
New Modules. You may purchase replacement modules in the same way as other
replacement parts.
VX4780 16-Channel Signal Conditioner User Manual
F–1
Appendix F: Replaceable Parts List
Using the Replaceable Parts List
This section contains a list of the mechanical and/or electrical components that
are replaceable for the <VX4780>. Use this list to identify and order replacement
parts. The following table describes each column in the parts list.
Parts List Column Descriptions
Column Column Name Description
1 Figure & Index Number Items in this section are referenced by figure and index numbers to the exploded view
illustrations that follow.
2 Tektronix Part Number Use this part number when ordering replacement parts from Tektronix.
3 and 4 Serial Number Column three indicates the serial number at which the part was first effective. Column four
indicates the serial number at which the part was discontinued. No entries indicates the part is
good for all serial numbers.
5 Qty This indicates the quantity of parts used.
6 Name & Description An item name is separated from the description by a colon (:). Because of space limitations, an
item name may sometimes appear as incomplete. Use the U.S. Federal Catalog handbook
H6-1 for further item name identification.
7 Mfr. Code This indicates the code of the actual manufacturer of the part.
8 Mfr. Part Number This indicates the actual manufacturer’s or vendor’s part number.
Abbreviations
Mfr. Code to Manufacturer
Cross Index
Abbreviations conform to American National Standard ANSI Y1.1–1972.
The table titled Manufacturers Cross Index shows codes, names, and addresses
of manufacturers or vendors of components listed in the parts list.
F–2
VX4780 16-Channel Signal Conditioner User Manual
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