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USING THIS GUIDE

This reference and programming guide contains condensed
specifications, a summary of front panel operating controls.
and IEEE-488 programming commands and examples for
the Models 194A. 1941, and 1944A. It is intended to pro-
vide a quick reference to the many available features of your
instrument as well as the many programming commands
available to control the instrument over the IEEE-488 bus.


Because of the limited amount space available in this guide.
many details abourinstrument operation will not be found
here. Refer to the Model 194A Instwction Manual for
aspects of instrument operation not covered in this guide.


This guide describes the following aspects of the Model
194A:

l Front panel operation including XY mode.
l A description of mathematical functions.
* Input and output signal connections.
l IEEE-488 programming information, including commands,
data and status formats. and exampkprograms for typical
COntrOllers.




01989, Keithley Instruments. Inc.
28775 Aurora Road
Cleveland, Ohio 44139
Document Number: 194A-900-01 Rev. A

1
CONTENTS

CONDENSED SPECIFICATIONS .~. . . 4
ENGlNEERlNG "NITS CONVERSION . .~. .~.~.~.._5
SAFElYPRECAUTIONS...................... 6
FRONT PANEL FEATURES AND OPERATlON.. . 7
Display
Annunciators
Genera, Display Messages
Shift Functions
Mathematical Functions
Ratio and Difference Modes
Range
Data Entry
Programmable Parameters
Rate and Samples Programming
Recalling Data
Trigger
Channel Selection
Input Coupling
Zero
Filter
FRONT PANEL PROGRAMS., _~__~_ 25
SetUP-
status
Reset
XY Mode
INPUT AND OUTPUT CONNECTIONS . 3,
A/D Module InpuffOutput Connections
Analog Output Connections
Enernal Clock
IEEE-466 PROGRAMMING. _, 36
Device-dependent Commands
TRANSLATOR MODE.. _. _ .~__ _ _~~ 56
CONTROLLER PROGRAMS t t __ _ __ 56
IBM XT or PC (with CEC Interface1
Hewlett-Pock& 300 Series Compac
ASCII CHARACTER CODES AND IEEE-466
MULTILINE INTERFACE COMMAND MESSAGES 62

3
CONDENSED SPECIFICATIONS




INPUT IMPEDANCE:
MAXIMUM ALLOWABLE
MAXIMUM SAMPLING RATE: lMHz
,
I
1MO in parallel with less than 47pF.
INPUT: 260" peak, 2 x 10'" Hz.
et 6.bit resolution;
100kHz et 16.bit resolution.
MATH FUNCTIONS: Average, Peak, Peak-to-Peak, TRMS,
Standard Deviation, Integral, Waveform.
FRONT PANEL PROGRAMS: IEEE-466 Address, Self Test,
Digital Calibration, Calibration Storage, X Output Full Scale,
Y Output Full Scale, Z Output Blanking Level,
DISPLAY Fourteen digit alphanumeric LED display.
RANGING: Manual or autoranging.
CONNECTORS: All I/O connectors are BNC except Real
Trme Output IDS-261 and IEEE-466 connectors.




4
ENGINEERING UNITS AND
SCIENTIFIC NOTATION
CONVERSION


Engineering
Prefix Symbol Scientific Notation
I

pico-
"anO-
micro-
milli-
kilo-
mega-
giga-
tera-
peta-




5
SAFETY PRECAUTIONS

The following safety precautions should be observed before
using the Model 194A:

1. Before operation. ground the instrument through-a pro-
perly earth grounded power receptacle
2. Do not exceed 30" rms between input low and earth
ground.
3. Do not exceed the maximum allowable input 8s defined
in the condensed specifications section of this guide
4. Before servicing. disconnect the Model lg4A from the
power line and all other equipment.
5. Do not touch any terminals while the instrument is turn-
ed on or connected to any other equipment or sources.
FRONT PANEL FEATURES
AND OPERATION

DISPLAY

DESCRIPTION

The Model lg4A display consists of fourteen 14.segment
LED units which display both instrument readings as well
as many messages to augment the variow operational
modes. The basic display format for readings includes the
voltage value, units ImV or VI. mathematical function (for
example AVG for average) and channel number (1 or 2).
Channel 2 is available only for those units equipped with
a Model lg44A AID module in the CARD 2 location.


The display can be operated singlechannel or dualchannel,
as selected with the CHANNEL button. The selected than-
nel also dictates which channel is affected by pressing other
buttons. Most other modes cannot be changed when the
display is in the dual-channel mode



DISPLAY EXAMPLES

Typical examples for the display modes include:

Channel 1 Average Reading: -1.2500 V AVG 1.
Channel 2 TRMS Reading: 0.3450 mV RMS 2.
Dual Channel Reading: -1.2500 0.3450
ANNUNCIATORS

Front panel annunciators indicate when a number of front
panel modes are selected as described below:

IEEE-488 STATUS: The TALK, LISTEN, and REMOTE in-
dicators show when the instrument has been placed in
those respective modes via programming commands sent
wer the IEEE-488 bus. These indicators are not operational
during front panel operation.

ZERO: Indicates when a baseline measurement is being sub-
tracted from subsequent measurements.

FILTER: Shows when either the 5OkHz or 5OOkHr analog
filters are enabled.

SGUCONT: Indicates when the instrument is in the single
or ccmtinuou* trigger.

SLOPE: Shows whether the instrument will be triggered on
the rising or falling edge of an input signal waveform.

`CPLG: Indicates BC or dc input coupling. Ground coupling
is selected when both indicators are off.

AUTO: Shows when the instrument is in the autorange
mode.

SHW Shows when the shift mode has been enabled by
pressing the shift key. Shifted modes are marked below the
respective control buttons.

RECALL: Indicates when the recall mode is in effect. This
mode allows access to individual samples in the measure-
ment buffer.


8
GENERAL DISPLAY MESSAGES

Display messages that may occur during general front panel
cpererlcn are summarimzi below. The unit also has a number
of specific messages associated with the various operating
modes, as described in the instruction manual.


MESSAGE DESCRIPTION


OFLO Overrange input applied for at
least one sample.
SHIFTLESS KEY Shift function invoked for key
not having one.
NMSR TOO SMALL Too small a value keyed in dur-
ing data entry.
iwmi7
mo LARGE Too big a value keyed in during
data entry.




SHIFT FUNCTIONS
DESCRIPTION

Many of the front panel keys have a secondary function
which is placed intoaffect by pressing theSHIFT key before
pressing that particular button. Each shifted function is
listed below the key in question. For example, pressing
SHIFT ZERO VAL allows a baseline value to be keyed in from
the front panel. While the shift function is enabled. the
associated indicator will be on. Pressing a key which does
not have a~shifted function will result in the following display
message:


SHIFTLESS KEY




MATHEMATICAL FUNCTIONS




DESCRIPTION

The Model 1g4A has a number of mathematical functions
that can be applied to the measurement. If the instrument

10
is in a continuous trigger mode. a single math function, Once
selected, can be applied to successive measurements. In
a single trigger mode, a variety of different math functions
can be applied to a single measurement. Each mathematical
function can be enabled by pressing SHIFT followed by the
corresponding key.



OPERATION

WAVEFORM: Displays the individual sample occurring at
the trigger point, or thesample as close as possible to the
trigger point. Example: 1.2345 V DC 1.

PK TO PK: Displays the peak--to-peak value of the measure-
ment, which is calculated by subtracting the most negative
sample from the most positive samples
Eample: 2.3410 V P-P 1.

STD DEW Displays the standard deviation of the measure-
ment, which shows how far the samples deviate from the
average of the measurement. Example: -12.341 V STD 1.

INTEGRAL Displays the integral of the measurement, which
is the area under a curve bounded by the measurement
amplitude and the measurement duration.
Example: 800.23 VS 2.

AVG: Shows the average of the measurement, which is
calculated by dividing the sum of all the samples ~bvthe
number of sample. Example: -16.225 V AVG 1.

TRMS: Displays the true rms value of the meas~rment. Ex-
ample: 31.800 V RMS 1.

PEAK: Shows the most positive or mrxt negative sample
in the measurement. Example: 1.1220 V PK+ 1. Press
repeatedly to alternate between positive and negative peak.
RATIO AND DIFFERENCE
MODES

(
0 0~0
00000



DESCRIPTION

The ratio and difference modes allow you to divide the chat-
nel 1 reading by the channel 2 reading or to subtract the
channel 2 reading fmm the channel 1 reading. In order to
use either of these modes, the optional Model 1944A A/D
Module must be installed in the CARD 2 location. If there
is no second channel installed, pressing either CHl-CHZ or
CHl+CHZ module installed will result in the following
message:

NOAiDINCH2



OPERATION

CHlrCH2 IRatio): To display the ratio between the two
channels, press SHIFT CHltCH2. The instrument will then
display the ratio as in this example: 1.2367 V l/2.


12
CHI-CH2 (Differencel: To display the difference between
the two channekpress SHIFT CHl-CHZ. The instrument
will then display the difference between the two channels.
as in this examole: 2.4000 V 1-2.




RANGE




DESCRIPTION

The ranging controls give you control over sensitivity of the
measurement The range may be selected either on an
automatic or manual basis. When using manual ranging,
the lowest rangepossible without overranging the instru-
ment should be used to maximize accuracy and resolution.




13
OPERATION

AUTO: The AUTO button toggles the instrument between
auto and manual ranging. The AUTO indicator will be on
when in autoranging.

Uprange: Pressing uprange moves the instrument to the
next higher range until the highest (2OOVl range is reach-
ed, Uprange also cancels autorange if that mode is presently
enabled. Uprange is also used with various other functions
such as data entry and recall.

Downrange: This key moves the instrument to the next
lower range when pressed until the lowest I32OmVl range
is reached. Downrange also cancels autorange if enabled.
and it is used with various other functions such as data en-
try and recall.




14
The Data Entry keys allow the entry of numeric data into
those functions requiring values. These keys are used to
program values for rate. samples, trigger kvel. zero, and trig
get delay. During the entry process, the keyed in digits will
appear on the display.



OPERATION

Numeric Keys (O-9. +/-,. I: These keys enter actual
numeric data including decimal point and sign into the
display after the appropriate function has been entered.

ENTER: Pressing ENTER actually enters keyed in data into
the function in question.

CANCEL: May be used to cancel keyed in data and return
to the previous value.



15
Units Keys (MHz, kHz, Hzl: Determines the type of units
to be keyed in. Voltage or time or frequency units are
automatically chosen by the selected function. Pressing a
units key automatically enters the displayed data.

FRED/TIME: This key toggles the instrument between time
[email protected], msec, sl and frequency (MHz, kHz, Hz1 units. For ex-
ample, sampling rate may be entered either as time inter-
val or sampling frequency units.

Cursor Control: During the data entry process. the digit af-
fected by pressing a numeric keey will be indicated by a
flashing segment or digit. This cursor can be moved left or
right with the downrange or uprange buttons. respectively.




PROGRAMMABLE
PARAMETERS

Perameten to be programmed with the Date Entry keys are
summarized below, along with limits and resolution of each
parameter.




16
FUllCtkJ~ Limits bsohJtion

RATE Time Irsec-lsec 0.1 rrjec
Frequency lHz-1MHz HZ
SAMPLES No: l-65.535* Samples
lime: Opsec-65,534sec' 0.1 *ec
DELAY NO Samples: -65,536 to Samples
10'
`lime: -65,536 to 10'sec
LEVEL *20CW
ZERO "AL *2ocw
x output l-1OV nominal
Full Scale*'
Y Output*~ l-1OV nominal
Full Scale




RATE AND SAMPLES
PROGRAMMING
DESCRIPTION

A measurement is made up of a number of samples taken
at specific intervals. The number of samples in that
measurement, as well as how fast those samples are taken
can be programmed with the SAMPLES and RATE keys.
These parameters are entered with the Data Entry keeys
O~CB
the mode in question is enabled.

RATE: Sampling rate may be entered in time (Isec -lpecl
or frequency (IHI-1MHr). To program sampling rate, press
the RATE key and press the numeric buttons in the desired
sequence. Press the FRECUTIME key, as required, to enter
time or frequency units.

SAMPLES: The size of the measurement may be entered
as the number of samples 11-65.536) or measurement time
duration il#ec-65,536secl. To program the number of
samples, press SAMPLES and then key in the desired value
withythe numeric keys. Use FREQiTlME to select sampling
interval or number of samples, as desired.




RECALLING DATA
DESCRIPTION

Recall allcw you tc display individual samples within the
measurement. This mode is entered by using the RECALL
button. Once in the recall mode, individual samples may be
accessed on a sequenr,al or random basics.



OPERATION

To enter recall, simply press the RECALL button. While in
this mode, the RECALL indicator button will be on. To ac-
cess individual samples, either use the uprange or
downrange keys to access individual samples, or key in a
specific sample number and press the ENTER key.




TRIGGER




DESCRIPTION

The Model 194A may be triggered in a variety of different
ways: with the TRIGGER button. with an input ~pulse ap-
plied to the TRIGGER IN jack, from the other channel, or
from the input signal. When triggering from the input signal,
the slope and trigger level can be programmed.

19
OPERATION

SOURCE: To select the trigger scum?, press SOURCE
repeatedly until the desired mode is displayed: front panel
(TRIGGER), input signal, external. or other channel. Press
CHANNEL to save the selected source.

SGUCONI A measurement sequence can beperformed on
a continuous or single basis. In a continuous mode, the in-
strument repeatedly arms the A/D for the next trigger
measurement without requiring additional triggers. In the
single mode, B separate arm stimulus is required for each
measurement. SGLICONT toggles the instrument between
these two modes, as indicated by the respectiwindicator.

TRIGGER: When selected with the SOURCE key,pressing
this keeywill initiate a continuous or single measurement,
depending on the selected mode

SLOPE: Rising or falling edge triggering may be selected with
the SLOPE key only when input signal triggering is selected.
The annunciator next to the key indicates the selected mode

LEVEL: When triggering from the input signal, the actual
voltage level et which the unit is triggered may be selected
with the LEVEL key. Once this mode is entered, the voltage
is keyed in with the Data Entry keys.

DELAY Delay selects the number of samples between the
trigger and the first sample A positive or negative delay
may be selected. Delay may be entered in number of
samples or actual time by using the FREOrrlME key.




20
CHANNEL SELECTION




DESCRIPTION

For dualchannel units, the CHANNEL button allows you to
select one of three display modes: channel 1, channel 2,
or dual-channel display. For the two single-channel modes,
the displayed channel also determines which channel will
be affected by pressing other keys. In the dual channel
mode, most other buttons are inoperative




INPUT COUPLING




21
DESCRIPTION

The Model 194A has three available forms of input cowl-
ing: ac, de, and ground. The selected mode of coupling is
selected with the CPLG key and indicated by the respec-
tiw indicaton. When ground coupling is selected. both ac
and dc will be off.



OPERATION

The input circuit is configured as follows for the three
modes:

DC: A straight-through dc signal path is established.
AC: Instrument response is down 3dB at 2Hz.
Ground: The high and low terminals of the input amplifier
are shorted together.




ZERO
DESCRIPTION

Zero allows a baseline measurement to be subtracted from
subsequent measurements. The baseline can be obtained
either from an applied signal, or keyed in with the data en-
try keys. Once a baseline is established, it will be subtracted
from measurements until disabled. Any such zero will be
subtracted from the from the number to be displayed.



OPERATION

Zeroing an Applied Signal. Connect the signal to act as a
zero baseline with zero disabled and press the ZERO key.
Apply the measured signal and take readings es usual. The
displayed velue will be the difference between the applied
signal and the stored baseline value.



Keying in the Zero Value. To key in the baseline from the
front~panel,~pressSHIFT ZERO VAL key in the desired value
then press O\lTER. The baseline will remain in effect as long
as the ZERO indicator is on.




FILTER




23
DESCRIPTION

The Model 194A has two available
low-pass
analogfilters
with -3dB points of 5OkHHrand 5OOkHz. These filters are
selected with the FILTER buttton. When either the 5OkHz
or SOOkHz filters are enabled, the FILTERindicator will be on.



OPERATION

To select one of the filters. simply press the FILTER button
until the correct display message is shown 60kHz SOOkHz,
or off). When the desired filter is shown, press the CHAN-
NEL key to return to the previous mode.




24
FRONT PANEL PROGRAMS




0 0~0.0 0

00000

DESCRIPTION

The OTHER key allows selection of a number of front panel
program modes as follows: IEEE-488 address; self test;
digital calibration: NVRAM storage; X output full scale ahe;
Y output full scale value; and Z output blanking level. These
programs are numbered O-S, and are entered by pressing
the OTHER key. Once this mode has been entered. you can
either key in the appropriate digit, or use the uprange and
downrange keys to scroll through available programs.




OPERATION

IEEE-488 Address (SHIFT, OTHER, Ok Once entered. you
can program a valid primary address (O-301 by using the
Data Entry or oursOr keys and then pressing enter.

Self Test (SHIFT. OTHERV: Performs a self test on internal
instrument circuitry and will return appropriate error
messages.



25
Digital Calibretion (SHIFT. OTHER, 21: Digital calibration,
which requires specialized test equipment. is performed by
this program.

NVRAM Storage ISHIFT.OTHER.3): Stores calibration con-
stants in NVRAM once the unit is calibrated.

X Output Full Scale (SHIFT.OTHER,4): Programs the max-
imun voltage at the X analog output jack.

Y Output Full Scale (SHIFT. OTHER, 51: Sets the maximum
voltage of the Y analog 0utpuL

2 Output Blanking Level (SHIFT. OTHER.6): Determines the
blanking level at the 2 analog output.




SETUP




[email protected]

DESCRIPTION
I'
Setup allows you to store up to two different instrument
configurations in NVRAM. These setups can then be later


26
recalled. thus simplifying instrument configuration for a
variety of different test procedures.



OPERATION

Saving Setups: Select the channel !or scanner) to be con-
figured and program the desired modes. Press the SETUP
button twice followed by the desired setup number W2).
Press ENTER to store the selected configuration. Setup 0
contains the fectoly defaults and Cannot be reprogrammed.

Recalling Setups: Press SETUP followed by the desire setup
number. Press the ENTER key to recall the desired setup




STATUS




DESCRIPTION

The current instrument status for both channels. ten be
determined by recalling instrument status with STATUS key.

27
The returned status velues will depend on the jxesent
selected operating modes.



OPERATION

To access instrument status, simply press the STATUS key
once, the unit will display the following stetos parameters
in the following order, moving through the list et about one
item per second:

Zero value
Filter status (50kHz or SOOkHzj
Trigger *cum*
Wgger mode
Trigger delay
migger level
Sample rate
Measurement size
Maximum semple rate for each resolution




RESET

DESCRIPTION

The RESET key allows wu to quickly return the instrument
to the power-on default configuration (setup 1). Both A/D
channels will be effected by this key.



OPERATION

lb simulate a power on reset, simply press SHIFT RESET.


28
XY MODE




DESCRIPTION

The XY mode allows you to plot your data on a display
device such es a CRT, o*cilloscope, or plotter. Connections
to these plotting devices is made through* the X, Y, end
2 analog output jsck on the rear panel. Various scaling fac-
tom cm be applied to the data before being plotted.



OPERATION

XY MODE: Enters the XY mode and ellows the *election
of the type of plotting device: CRT, oscilloxopa or plotter.

XY DATA: Allows you to select the source of data to be
displayed. individual samples from the measurement buf-
fer, or readings from the display buffer for either channel
1 or channel 2.

XY TRIG: Used to *tart and stop the analog output
sequence.




29
XY ZOOM: Provides a methad of scaling data located in the
buffer to the display window.

XY PAN: Controls which data point is the first displayed
in the window.




30
INPUT AND OUTPUT
CONNECTIONS

A/D MODULE INPUT/OUTPUT
CONNECTIONS




DESCRIPTION

Each A/D module has several input D, output connectors
on the rear panel for voltage signal input, real time output,
and trigger input and output. Each of these connectors is
briefly described below.



OPERATION

VOLTAGE INPUT: All voltage input signals are applied to this
SNC jack for processing and AID conversion. Note that the
maximum input voltage is 25OVps~ak, 2 x 10,`V Hz. The
maximum cmnmon mode voltage is 30%

REAL TIME OUTPUT A/D data at the sampling rate may
be read via this output. Data can be transmitted in S-bit
or %-bit format This connector is also used to select bet-
ween internal and external sample rate clocks.

TRIGGER IN: A negative*oing pulse at TTL levels llO$c+ec
minimum) can be applied to this jack to one trigger a
measurement. External triggering must be selected with the
SOURCE key before this connector is active



31
TRIGGER OUT A negative going lO#sec pulee et TTL levels
will appear et this jack when a valid meaeurement trigger
occurs. The pulse will occur regardless of the selected trig-




ANALOG OUTPUT
CONNECTIONS




DESCRlPTlON

The analog output includes three jacks located on the rear
panel. labeled X, Y, and 2. Signals appearing at these jacks
are controlled by the XY mode. Each jack is a standard BNC
m""eCtOL

X OUTPUTr This signal, which provides time information,
should be used as en X-axis signal for a plotter or CRT.

Y OUTPUT The Y output provides amplitude about the
verlo~s samples, and should be used as a Y-axis signal for
the CRT and plotter, and vertical input information for an
oscilloscope.

Z OUTPUT: The Z output provides a blanking pulse for a
CRT. en external triggerpulse for an oeoillosoope, of a pen
up signal for e plotter.

32
EXTERNAL CLOCK




DESCRIPTION

The external clock jacks provide methods of synchronir-
ing two or more Model 194s together to a common time
base. as described below.



OPERATION

CLK IN: An externally generated 1OMHz clock et TTL levels
can be applied to this input to synchronize sample taking
to an external time base. Detection and switching is
a"tOmatic

CLK OUT: Normally. the internal 1OMHz clock (TTL levels1
of the Model lg4A will appear et this output. If the unit
Is operating with en external time base, the external clock
rate will appear et CLK OUT instead.

Synchronizing units: To synchronize units, connect the CLK
OUT of the master unit to the CLK in of the dave unit. Other
unite may be daisy chained in a similer manner.




33
IEEE-488 PROGRAMMING

DEVICE-DEPENDENT COMMANDS


FUNCTION
FO Waveform bmple at trigger
point)
Fl Average
F2 TRMS
F3 + Peak
F4 - Peek
FS Peak-to-oeak
FS Standard deviation
F7 Integral
F20 CHI-CHZ
F21 CHlICH2




Auto
320mV
3.2V
32v
2oov
Cancel auto lst*y on present
range)
TRIGGER
TO Continuous, talk
n Single, talk
T2 Continuous. GET
T3 Single, GET
T4 Continuous, X
T5 Single, X
T6 Continuous, external
T7 Single, external
T20.m Continuous, + slope. level m
i-ZOOrmr+2OOV)
T21.m Single, + slope, level m
(-200~ms+200Vl
T22.m Continuous, - slope, level m
(-200sm~+200Vl
T23.m Single, - *lope, level m
I-200~m~+ZOOV)
124 Continuous, other channel
T26 Single, other channel
T26 Continuous, immediate
T27 Single, immediate
T30 Start plotter
T31 Stop plotter




36
De& in set ~-65.536~m_clE71
`. ,,I, .,,,
2 `i,

~,,. ,"...Y.. .,.,., :~ :~ ,~,,.,,
( DATA FORMAT
GO `ASCII; 1 rdg. prefix on, suffix off
Gl ASCII. 1 rdg, prefix off, suffix off
G2 ASCII, 1 rdg, prefix an. suffix on
G3 *SC11. n rdgs. prefix on. suffix off
G4 ASCII. n rdgs. prefix 0% suffix ofl
ASCII, n rdgs. prefix oh suffix on
ii: Binary, n rdgs. prefix off, suffir
Off
G7 Binary, n rdgs Ibyte countI. p~refix
I off. suffix off




37
02.2 scope mode
02.3 Future expansion
02.4 Slow plot (XY analog plotters
02.5 Strip chart
03.0 Measurement buffer
03.1 64k RAM buffer
03.2 Display readings
03;3 IEEE-488 reading ~buffer
04.m m-X output full *tale voltage
(1 smsl0)
05.m m=Y output full scale voltage
(1 smrlo)
06.m m=Z output blanking level
U=high, O=loW
07.m m=XY zoom Yal"e
(0.1 rmslooo)
06.m m=XY pan value
I-65.536ams65.5361
09 start plotter




pointer to m.
B3.m Set reading buffer start pointer to
I tn. I

36
READING BUFFER
QO Reading buffer off.
Ql Linear reading buffer on.
Q2 Circular reading buffer on.~




F
flLTEi7
PO
F1
Filter off
500kHz filter
F2 50kHz filter




Z3.m Use value m as baseline value
(-200~ms+200V)
24 22 + Zl
Z5.m 23 +~Zl (-ZOOsms+ZOOVI




INPUT COUPLING
IO DC coupling
I1 AC coupling
12 Ground coupling




39
STATUS
uo
Ul Error status
u2 Data *muus
u3 Zero IZ) parameter
u4 Delay (WI parameter
u5 Number samples (NI parameter
U6 Sample rate 61 parameter
U8 Trigger levsl
us Measurement buffer start pointer
UlO Measurement buffer end pointer
Ull Reading buffer start pointer
u12 Get Translator list




M32 Error




40
TERMINATOR
Ylll Program m as single terminator
Yn,m Program mn as dual terminator
Y (DELI No terminator




RECALL
A0 Recall factory setup
Al Recall setup 1
A2 Recall setup 2




41
HIT SUTTDN
Hi7 Act as if button n (l-381 has been
pressed




DISPLAY
DaaaaX Display ASCII characters aaaa 114
maximum)
DX Return to normal display mode




SELF TEST
Jl Ul self test byte =1: fail




EXECUTE
X Execute other devicedependent
commands




42
Figure 1. SRQ Mask and Status Byte Format




Figure 2. ASCII Data Format (GO to G5)


43
Figure 3. Binary Data Format (Cont.)
45
FUNCTION (FM)
OO=WAVEFORM
Ol=AVERAGE*
OZ=TRMS
03=+PEAK
04=-PEAK
06=PEAK TO PEAK
06=STANDARD DEVlATlON
07=INTEGRAL
20=CHl-CH2
21=CHl/CH2

RANGE (Ann)
O=AUTO'
1=32OmV
2=3.2V
3=32V
4=2OOV

TRIGGER (mn)
OO=CONTINUOUS, TALK
Ol=SINGLE. TALK
OZ=CONTINUOUS, GET
03=SINGLE, GET
04=CONTINUOUS, X
05=SINGLE, X
OB=CONTINUOUS, EXTERNAL
07=SINGLE, EXTERNAL
ZO=CONTINUOUS, +SLOPE
21=SINGLE, +SLDPE


Figure 4. UO Status Word Format

46
22=CONTINUOUS, -SLOPE
23=SINGLE, -SLOPE
24=CONTINUOUS, OTHER CHANNEL
25=SINGLE, OTHER CHANNEL
26=CONTINUOUS,~ IMMEDIATE*
27=SlNGLE, IMMEDIATE
3O=START PLOTTING
31=STOP PLOTTING

FILTER (Pn)
O=OFF'
1=600kHr
2=50kHz

ZERO (Zn)
O=DISABLED*
1 =ENABLED
2=SAVE MEAS
S=USE VAL.
4=Zl + 22
5=Zl f-Z3

EOI, BUS HOLD OFF (Kn)
O=EOI, HOLD OFF'
l=NO EOI, HOLD OFFS
2=EOI, NO HOLD OFF
3=NO EOI, NO HOLD OFF

BUTTON PRESSED (Hnn)
OO=NONE
01 =ZERO
OZ=FILTER
03=TRIGGER
04=SGL/CONT
05=SOURCE
06=DELAY


Figure 4. UO Status Word Format (Cont.)

47
07=SLOPE
OII=LEVEL
09=SCAN
lO=CPLG
ll=SAMPLES
lZ=RATE
13=LOCAL
14=CHANNEL
15=AUTO

16=%
l7=.,

18=SHIFT
lS=RECALL
2O=sTATUS
Zl=ENTER
ZZ=CANCEL
ZB=FREQ/TIME
24=7
25=4
26=1
27=8
28=5
29=2
3O=S
31=6
32=3
33=6
34=*
35=*
36=MHz
37=kHr
38~Hr




Figure 4. UO Status Word Format (Cont.)

48
INPUT COUPLING (In)
O=DC COUPLING'
,=AC COUPLING
Z=GROUND COUPLING

RECALL SETUP (A")
O=FACTORY SETUP'
l=SETUP 1'
Z=SETUP~ 2

SAVE (Ln)
l=SAVE SETUP I*
2=SAVE SETUP 2
4=CALlBRATE USING VALUE
5=STORE CAL IN NVRAM

READING BUFFER (Qn)
O=DISABLED*
l=LINEAR BUFFER
2=CIRCULAR BUFFER, OVERWRITE

DATA FORM&T IGn,
O=ASCII. PREFIX ON, SUFFIX OFF, ,RDG
l=ASCII, PREFIX OFF, SUFFlX OFF, ,RDG
2=ASCII, PREFIX ON, SUFFlX ON, IRDG'
3=ASCIL PREFIX ON. SUFFIX OFF. n RDGS
4=ASCII. PREFIX OFF, SUFFIX OF+, n RDGS
5=ASCII. PREFIX ON, SUFFIX ON, n RDGS
B=BINARY, PREFIX OFF, SUFFIX OFF
7=8INARY, PREFIX OFF, SUFFIX 0FF;BYTE COUNT

SELF TEST (Jnn)
CODE/MEANING
OO=NO ERROR
Ol=SELFTEST COMPLETE, NO ERROR
(GOES TO 00 IJO READ]


Flgure 4. UO Status Word Format (Cont.)

49
02=NOT USED
03=NOT USED
04=NOT USED
05=NOT YSED
06=NOT USED
07=NOT USED
OB=RAM ERROR ON MOTHERBOARD
09=ROM ERROR ON MOTHERBOARD
lX=A/D ERROR ON CHl
(SEE TABLE BELOW FOR X MEANING)
2X=A/D ERROR ON CH2
ISEE TABLE BELOW FOR X MEANING)

A/D ERROR CODES
O=NOISY AID
l=NOT USED
2=INOPERATIVE CAL ADJUSTMENT
3=NOT USED
4=NOT USED
5=TIMEBASE ERROR
fi=NOT USED
7=RAM ERROR

CHANNEL (Cm)
Ol=CHANNEL I*
02=CHANNEL 2
12=COMPOSiTE CHANNEL

SRQ (Mnnn)
OOO=DlSABLED'
OOl=OVERFLOW
002=DATA
004=HIT BUTTON
OOB=READING DONE
O,S=~READY
032=ERROR


Figure 4. UO Status Word Format (Cont.)

50
TERMINATOR(Ynnnnnn)
nnnnnn=YlASCII)
000000=No TERMINATOR
O,SOlO=CR LF*

TERMINATOR
DEFAULT CR LF




Figure 4. UO Status Word Format (Cont.)
BUTTON NUMBERS USED BY HIT COMMAND
AND RETURNED IN UO STATUS




0 NOW 21
1 ZERO 22
2 Flu-m 28
3 TRIGGER 24

: SGL/CONT
SOURCE 26
25
6 DELAY 27
7 SLOP& 28
8 EE 29
9 80
10 CPLG 31
11 SAMPLES 32
12 RAT?2 33
I3 LOCAL 84
14 ChxNNEL
I5 Au-r0 E
16 uP=JW 37
I7 DOwnrange 38
18 SHFl
I9 RECALL
20 STATUS




52
Figure 5. Ul Status Word Format
53
54
Figure 7. U3-Ull Status Word Formats




55
TRANSLATOR MODE

DESCRIPTION

The Translator mode allows you to substitute English-like
words in place of device-dependent commands or com-
mands strings. For example the word SAMPLES could take
the place of the command NlOOOX, which programs the
instrument to take 1000 samples. A single word can also
replace a group of commands at one time For example. the
word SETUP1 could be used to replace the following corn-
mand string: FlS+lOON250W+-25Z1P2X.


RESERVED WORDS AND SYMBOL

Tmnslator resewed words and symbol are listed~below, along
with a brief description of each word.

Reserved Word Description


ALIAS Define Translator words. enable
Translator.
NEW Enable Translator, combine words.
OLD Disable Translator.
LIST Get list of Tmnslator words from
instrument.
FORGET Purge Translator words.
Terminate Translator command
string.




56
EXAMPLES

"ALIAS SETUP1 ROFlX ;* - Defines the word SETUP! in
place of ROFlX.
"ALIAS TE'34 N1000S+1010X ;* - Defines TEST4 in place
of N1000S+1010X.




57
CONTROLLER PROGRAMS

The following programs have been supplied as a simple aid
to demonstrate basic programming techniques and are not
intended to suit specific needs. Each program allows you
send a device-dependent command string to the instrument
and obtain Andydisplay an instrument reading string. The
returned data is an ASCII string variable of the form:

NAVG+1.2345 CR LF



Here, CR LF represents the default carriage return, line feed
terminator and will not normally be displayed.


A note included with each program indicates modifications
necessary to provide a numeric variable of the form:

11.2345


Programs for the following contmllers are included:

IBM PC or Xl (with CEC IEEE-488 interface).
Hewlett-Packard 300 series computer running BASIC,




58
IBM XT or PC (with CEC Interface)
HEWLETFPACKARD SERIES 300


The following program sends a command string to the
Model 194A from a Hewlett-Packard Model 310 computer
and displays the instrumsnf reading string on the computer
CRT. The computer must be equipped with the HP82937
GPIB Interface and HP BASIC 4.0



DIRECTIONS

1. Using the front panel program feature, set the primary
address of the Model 194A to 9.
2. With the power off. connect the Model 194A to the
~HP82937A GPIB interface installed in the 9816 computer.
3. Type EDIT and press the EXEC key.
4. Enter the lines in the program below, using the ENTER
key after each line
6. Press the 9816 RUN key and type in the desired com-
mand string at the command prompt. For example, to
place the instrument in the autorange and average modes,
type in ROFIX and press the ENTER key.
6. The instrument reading string will then appear on the
CRT. A typical display is: DAVG+1.2345.




60
PROGRAM COMMENTS


IBRE"OTE789 Place 194A in remote
20 INPUT" COFiMClNDPrompt for and input command.
STRING";A*
30 OUTPU*09;** Address 194A to listen, send
string.
40 ENTER 709; BB Address 194A to talk, input
readina.
Display reading string.
Repeat.
ASCII Character Codes and
IEEE-488 Multiline Interface
Command Messaaes
Decimal Hexadecimal ASCII I
0 00 NUL
1 01 SOH GTL
2 02 8Tx
3 03 ETX
4 04 EOT SDC
6 05 ENQ PPC

; 06
07 ACK
8EL
8 08 8S GET
9 09 HT TCT
10 OA LF
11 08 VT
12 oc FF-
13 OD CR
14 OE so
15 OF SI
16 10 DLE
17 DC1 LLO


DCL
PPU


24 18 CAN SPE
26 19 SPD
26 IA

28
27 1c
18 Z
29 ID GS
30 lE RS
hAmal Hexadecimal ASCII IEEE-488 Message'

32 20 ASP MLAO
33 21 I MLAl
34 22 " MLA 2
# MIA3


ii
39
ii
~27
?i
&
MLA 4
MLA 6
MLA7
5


40 28 i MLA 8
41 29 1 MLA 9
42 2A ' _ MLA10
43 26 + MIA 11
44 2c MLA 12
46 2D MLA 13
46 2E
47 2F i MLA 14
15
48 30 0 MLA16
49 31 1 MLA 17
50 32 2 MLA 18
33 3 MLAIS
z: 34 4 MLA 20
53 35 5 MLA 21
54 36 6 MLA 22
66 ~7 MLA 23
56 ,";: 8 MLA 24
57 39 9 MLA 26
58 3A MLA 26
59 38 MLA 27
;
MLA 28
60
61 ;; = MLA 29
62 3E > MLA 30
63 3F ? UNL
Decimal Hexadecimal ASCII IEEE-468 Message*
64 40 f MTA 0
65 41 MTA 1
66 42 B MTA 2
67 43 C MTA 3
68 44 D MTA 4
69 45 E MTA 5
70 46 F MTA 6
71 47
48 ii MTA 7
8
49 I MTA 9
74 4A J MTA 10
75 48 K MTA 11
76 4c L MTA 12
77 4D M MTA 13
78 4E N MTA 14
4F 0 MTA 15
2 ~~50 P MTA 16
81 51 Q MTA 17
62 52 R MTA 18
63 53 S MTA 19
84 64 T MTA 20
U MTA 21
V MTA 22
87 57 W MTA 23
88 5* X MTA 24
Y MTA 25
2 MTA 26
i MTA 28
29
27


A MTA 30
95 5F UNT
leclmal Hexadecimal ASCII IEEE-488 Message'

96 60 MSA O.PPE
97 61 MSA 1,PPE
98 62 MSA 2,PPE
99 63 MSA 3,PPE
100 64 MSA 4,PPE
101 65 MSA 5,PPE
102 68 MSA 6,PPE
103 67 MSA 7,PPE
104 68 MSA 8,PPE
105 69 MSA 9.PPE
106 ETA MSA 10,PPE
107 66 : MSA ll,PPE
108 6C I MSA 12,PPE
109 6D m MSA 13,PPE
110 6E n MSA 14,PPE
111 6F MSA 15;PPE
112 70 MSA 16,PPD
113 71 MSA 17,PPD
114 72 MSA ILPPD
115 MSA 19,PPD
116 :: MSA 20,PPD
117 76 MSA 21,PPD
118 76 MSA 22,PPD
119 MSA 23,PPD
120 :; MSA 24,PPD
12, 79 MSA 25,PPD
122 7A MSA 26,PPD
123 76 MSA 27,PPD
124 7c MSA 28,PPD
125 7D MSA 29,PPD
126 7E MSA 30,PPD
127 7F DEL