National Instruments GPIB Device Simulator EPROM Owner's manual

© Copyright 1993 National Instruments Corporation.
All Rights Reserved.
LabVIEW®is a trademark of National Instruments Corporation.
Product and company names are trademarks or trade names of their respective companies.
GPIB Device Simulator EPROM
Programming Manual
November 1993 Edition
Part Number 320638-01

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[phone]
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Technical support fax: [phone]
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Sweden 08 730 49 70, Switzerland 056 27 00 20, U.K. 0635 523545

© National Instruments Corp. iii GPIB Device Simulator EPROM
Contents
GPIB Device Simulator EPROM..............................................................1
Setting the Address.....................................................................1
Data Formats.............................................................................................2
Waveform Format.......................................................................2
Floating-Point Number Format...................................................2
Simulator Commands................................................................................2
Address Command .....................................................................2
Waveform Format Commands ...................................................3
Waveform Generation Commands .............................................4
Waveform Query Commands.....................................................4
"Multimeter Configuration" Commands ....................................5
Other Commands ........................................................................6
Command Summary .................................................................................8
Compatibility Commands .........................................................................9
LabVIEW®Examples...............................................................................10
LabWindows®Examples..........................................................................15
Figures
Figure 1. GPIB Device Simulator Set to Address 3 .............................1
Figure 2. Three ESR Bits Set by the Simulator ....................................6

© National Instruments Corp. 1 GPIB Device Simulator EPROM
GPIB Device Simulator EPROM
You can simulate the operation of a GPIB instrument by replacing the
EPROM inside a GPIB-232CT with the GPIB Device Simulator EPROM
(part number 702295-01). The GPIB-232CT will then act as a GPIB
instrument.
The Simulator functions like a GPIB oscilloscope in that it is capable of
returning waveforms in different configurations: ASCII, 8-bit unsigned
binary, and 16-bit signed binary. It is also capable of returning single values
in ASCII such as those returned by a multimeter.
Setting the Address
The default address of the GPIB Device Simulator EPROM is set using the
first five switches of the U20 dip switch inside the GPIB-232CT. All other
switch settings are ignored.
The first 5 switches set the address. Switch 1 is the least significant bit
(LSB) and switch 5 is the most significant bit (MSB). Figure 1 shows an
example of the Simulator set to address 3.
OFF
12345678
U20
LSB MSB
Figure 1. GPIB Device Simulator Set to Address 3
You change the address using the dip switches or by the sending the
Simulator the SADDR primary, secondary command. For example,
SADDR 1 sets the Simulator to address 1, and SADDR 2, 4sets the
Simulator to primary address 2 and secondary address 4.

GPIB Device Simulator EPROM 2 © National Instruments Corp.
Data Formats
Waveform Format
The Simulator returns a 128 point waveform in either ASCII or binary.
ASCII waveforms are preceded by the header CURVE. Binary waveforms
are preceded by a pound sign (#) and the number of bytes that are in the
waveform. All waveforms are terminated by a line feed <LF> character.
Floating Point ASCII (Default)
CURVE<space>num0,num1,...,num127<LF>
8-bit Unsigned Binary
#3128<Byte 0><Byte 1>...Byte<127><LF>
16-bit Signed Binary
#3256<MSB 0><LSB 0><MSB 1><LSB 1>...<MSB 127><LSB
127><LF>
Floating-Point Number Format
[+][-]1.2345E[+][-]0
Simulator Commands
The Simulator uses SCPI-like commands. The commands are shown in long
form; however, the Simulator only accepts the short form of the command.
In other words, only send the part of the command that is in uppercase
characters. You can send multiple commands to the Simulator by separating
them with a semicolon (;).
Address Command
SADDRess primary, secondary Sets the address (power-on
default – switch setting)
Example:SADDR 2 Set the address to 2
SADDR 3, 4 Set the primary address to 3
and the secondary address to 4

© National Instruments Corp. 3 GPIB Device Simulator EPROM
Waveform Format Commands
These commands format how the waveform data is returned by the
Simulator.
FORMat:DATA ASCii Floating point (Default)
INTeger,8 8-bit unsigned binary
INTeger,16 16-bit signed binary
FORMat:DATA? Returns the current waveform format
The following command changes the order of the bytes returned by
INTeger,16 encoding.
FORMat:BORDer NORMal Low byte first (Default)
SWAPped High byte first
FORMat:BORDer? Returns the current format of
the byte order
Example:FORM:DATA INT,16 Set the waveform format as
16-bit integers
FORM:DATA? Query the current waveform format.
For example, if the command was
issued after the preceding command, it
would return
FORM:DATA INT,16<LF>

GPIB Device Simulator EPROM 4 © National Instruments Corp.
Waveform Generation Commands
These commands generate a 128 point waveform of the specified type. The
number of cycles in the waveform is random. It can take 5 to 15 seconds to
generate the waveform depending on the format and type of the waveform.
Typically ASCII waveforms take longer than integer waveforms.
SOURce:FUNCtion SINusoid Sine waveform (Default)
SQUare Square waveform
NOISe Noisy sine waveform
RANDom Random noise waveform
PCHirp Chirp waveform
SOURce:FUNCtion? Returns the current
waveform type
Example: SOUR:FUNC SIN Generate a sinusoid waveform
SOUR:FUNC? Query the current waveform
type. For example, if the
command was issued after the
preceding command, it would
return SOUR:FUNC SIN<LF>
Waveform Query Commands
SENSe:DATA? Returns the waveform data in the
format specified by the waveform
format commands
SENSe:VOLTage:RANGe:OFFSet?Returns the Y offset for the
waveform in ASCII floating point
SENSe:VOLTage:RANGe? Returns the Y multiplier for the
waveform in ASCII floating point
SENSe:SWEep:TIME? Returns the X increment (1E-3) in
ASCII floating point

© National Instruments Corp. 5 GPIB Device Simulator EPROM
SENSe:VOLTage:HEADer? Returns all of the waveform
scaling information in the format
OFFSET=x.xxxxE+x,
RANGE=x.xxxxE+x,
TIME=1E-3<LF>
For integer-formatted waveforms, the offset and range is used to scale the raw
integer data–for example,
scaled.point(i) =(waveform.point(i) +offset) *range
Example:SENS:DATA? Query Simulator for the
waveform
SENS:VOLT:HEAD? Query Simulator for the
waveform scaling information
"Multimeter Configuration" Commands
These commands simulate the operation of a meter. They return one value
in ASCII floating point.
MEASure:DC? Returns a random value between
0 to +x in floating point ASCII.
The range of x depends on the
CONFigure:DC command
CONFigure:DC DEFault MEASure:DC? returns a number
between 0 and 10
MIN MEASure:DC? returns a number
between 0 and 1
MAX MEASure:DC? returns a number
between 0 and 100
CONFigure:DC? Returns the current configuration
setting
Example:CONF:DC MAX Set the maximum range
CONF:DC? Query the current DC range. For
example, if the command was
issued after the command above,
it would return
CONF:DC MAX<LF>
MEAS:DC? Queries one value, for example
1.2308<LF>

GPIB Device Simulator EPROM 6 © National Instruments Corp.
Other Commands
*IDN? Returns National Instruments
GPIB Device Simulator Rev
A.x <LF>
*RST Resets the Simulator to its default state
*TRG Triggers the Simulator and returns one
random reading (same as MEAS:DC?)
*TST? Simulates testing the Simulator.
Returns OK
*OPC Sets the operation complete bit in the
Standard Event Status Register (ESR)
*OPC? Returns the value of the OPC bit in the
ESR register
*ESR? Returns value of Standard Event Status
register as specified by FORM:SREG
Figure 2 illustrates the bits defined by the Simulator for the ESR register–
bit 7 (Power On), bit 5 (Command Error), and bit 0 (Operation Complete).
Bit 7 is set when the Simulator is powered on; bit 5 is set when the
Simulator receives an invalid command; and, bit 0 is set when the
Simulator receives the *OPC command. You can use the *ESR?
command to query the value of the ESR register. The value returned is in
either ASCII or HEX, as specified by the FORMat:SREGister
command. The ESR register is cleared after you read it.
12345670
Power On
Comm
a
Figure 2. Three ESR Bits Set by the Simulator

© National Instruments Corp. 7 GPIB Device Simulator EPROM
*ESE 0x## Sets value of Standard Event Status
(zero, x, mask in hex) Enable register
*ESE? Returns value of Standard Event Status
Enable register as specified by
FORM:SREG
*STB? Returns value of Status Byte register as
specified by FORM:SREG
*SRE 0x## Sets value of Service Request Enable
(zero, x, mask in hex) register
*SRE? Returns value of Service Request Enable
register as specified by FORM:SREG
*WAI Does not do anything; included to make
the Simulator IEEE 488.2 compatible
FORMat:SREGister ASCii Specifies the output of ESR, ESE, STB,
and SRE registers as an ASCII string
(default)
HEX Specifies the output of ESR, ESE, STB,
and SRE registers in hex
FORMat:SREGister? Returns the current format of the registers
SYStem:HELP? Returns a list of all of the commands.
Refer to Command Summary section.

GPIB Device Simulator EPROM 8 © National Instruments Corp.
Command Summary
SADDR
FORM:DATA ASC | INT,8 | INT,16 (?)
FORM:BORD NORM | SWAP (?)
SOUR:FUNC SIN | SQU | RAND | PCH (?)
SENS:DATA?
SENS:VOLT:RANG:OFFS?
SENS:VOLT:RANG?
SENS:SWE:TIME?
MEAS:DC?
CONF:DC MIN | MAX | DEF (?)
*IDN?
*RST
*TRG
*TST?
*OPC
*OPC?
*ESR?
*ESE 0x##
*ESE?
*STB?
*SRE 0x##
*SRE?
*WAI
FORM:SREG ASC | HEX (?)
SYS:HELP?
|– separates options for the command
(?)–indicates the command can be used to query the current state

© National Instruments Corp. 9 GPIB Device Simulator EPROM
Compatibility Commands
The new Simulator EPROM supports the following commands for
compatibility with the older EPROM. However, if multiple commands are
sent together, they must be separated using a semicolon (;).
E0xh0 (E zero, x, mask in hex) Causes the box to assert SRQ
whenever it has finished generating data in response to a W
command. The serial poll status is specified in h0.
E0x0 (E zero, x, zero) Disables asserting SRQ
G0 Output data as 2-byte integers
G1 Output data as ASCII floats separated by a comma
G2 Output data as ASCII floats separated by a comma
W1 Output a noisy square wave
W2 Output a sine wave
W3 Output a noisy sine wave
W4 Output random data
W5 Output a chirp waveform
Od0 (Letter O) Output d0 random 2-byte integers one at a time

GPIB Device Simulator EPROM 10 © National Instruments Corp.
LabVIEW Examples
Example 1
The following LabVIEW example shows how to set up the Simulator to
generate a square waveform, read the waveform, and plot the waveform on a
graph.

© National Instruments Corp. 11 GPIB Device Simulator EPROM
Example 2
The following LabVIEW example shows how to set up the Simulator to
assert an SRQ after it generates a sine waveform, read the waveform, and
plot the waveform on a graph.
Example continued on the next page.

GPIB Device Simulator EPROM 12 © National Instruments Corp.

© National Instruments Corp. 13 GPIB Device Simulator EPROM
Example 3
The following LabVIEW example shows how to set up the Simulator to
generate a noisy sine waveform in binary format, read the waveform, scale
the waveform, and plot the waveform on a graph.
Example continued on the next page.

GPIB Device Simulator EPROM 14 © National Instruments Corp.

© National Instruments Corp. 15 GPIB Device Simulator EPROM
LabWindows Examples
Example 1
REM The following example shows how to set up the
Simulator
REM to generate a square waveform, read the waveform, and
REM plot it on a graph.
DIM buffer AS STRING * 2000
DIM waveform#(128)
CALL ibfind ("DEV1", simulator%)
CALL ibpad (simulator%, 2) 'Simulator at address 2
CALL ibwrt (simulator%, "SOUR:FUNC SQU; SENS:DATA?")
CALL ibrd (simulator%, buffer$)
REM Discard header and convert ASCII data to
REM floating-point array
n% = Scan (buffer$, "%s[i6]>%128f[x]", waveform#())
uir.err% = YGraphPopup (waveform#(), 128, 4)
Example 2
REM The following example shows how to set up the
Simulator
REM to generate a noisy sine waveform, read the waveform,
REM and plot it on a graph. The waveform is transferred
in
REM 2-byte binary.
DIM buffer AS STRING * 2000
DIM waveform%(128)
CALL ibfind ("DEV1", simulator%)
CALL ibfind ("GPIB0", board%)
CALL ibpad (simulator%, 2) 'Simulator at address 2
CALL ibwrt (simulator%, "FORM:DATA INT,16;
SOUR:FUNC NOIS;SENS:DATA?")
CALL ibrd (simulator%, buffer$)

GPIB Device Simulator EPROM 16 © National Instruments Corp.
REM Convert the data from binary to numeric (must byte
swap)
n% = Scan (buffer$, "%128d[zi5]>%128d[o10]", waveform%())
uir.err% = YGraphPopup (waveform%(), 128, 1)

© National Instruments Corp. 17 GPIB Device Simulator EPROM
Example 3
REM The following example shows how to set up the
Simulator
REM to assert an SRQ after it generates a sine waveform,
REM read the waveform and plot it on a graph.
DIM buffer AS STRING * 2000
DIM waveform#(128)
CALL ibfind ("DEV1", simulator%)
CALL ibfind ("GPIB0", board%)
CALL ibconfig (board%, 7, 0) 'Disable auto serial
polling
CALL ibpad (simulator%, 2) 'Simulator at address 2
CALL ibwrt (simulator%, "*ESE 0x01; *SRE 0x20;
SOUR:FUNC SIN; *OPC;")
CALL ibwait (board%, &H5000) 'Wait for SRQ
CALL ibrsp (simulator%, spbyte%) 'Get serial poll byte
CALL ibwrt (simulator%, "*ESR?;") 'Read ESR
CALL ibrd (simulator%, buffer$)
CALL ibwrt (simulator%, "SENS:DATA?") 'Query the
waveform
CALL ibrd (simulator%, buffer$)
REM Discard header and convert ASCII data to
REM floating-point array
n% = Scan (buffer$, "%s[i6]>%128f[x]", waveform#())
uir.err% = YGraphPopup (waveform#(), 128, 4)