Gould 400 Series User manual

Digital Storage Oscilloscopes
Operators Manual
Gould 400 Series

Gould 400 Series
Digital Storage Oscilloscopes
Operators Manual
Copyright@1990 Gould lnc., Instruments Division
(Gould Electronics Ltd.)

400 Operators Manual
Contents
Introduction
Getting Started
1
Advanced Features
2
The Menus
3
Performance Checking
4
Waveform Processing
5
Battery Unit Operation
6
Alphabetical Summary
7
Appendix 1 Error Messages
A1
Appendix 2 Specification
A2
Appendix 3 Remote
Operation
A3
A
ppendix 4 Front & Back
Pictures
I Service Facilities

Contents 400 Operators Manual
Introduction
2.5
Plot
2.5.1
Internal Colour Plotter
Oti
1. Getting Started
2.5.2
Pens
1.1 Safety and Power Requirements 2.5.3
Pen Changing
1.1.1
International Safety Warning
2.5.4
Paper Selection
1.1.2
Grounding
2.5.5
Paper Loading
1.1.3
Live Parts
2.5.6
Internal plotting
1.1.4
Ventilation and Dust
2.5.7
External plots
1.1.5
Operating Temperatures
2.5.8
Plot positioning and scaling
1.1.6
Power & Frequency
Requirements 2.6
Data Transfer
1.1.7
Fuse Requirements
2.6.1
Syntax
2.6.2
Receiving Data
1.2 Using the Buttons 2.6.3
Error Status
1.3 Start-Up Display
1.4 Obtaining a Trace
2.7
Real Time Clock
1.4.1
AUTO SETUP
1.4.2
Channel Selection (Off/On/lnv)
3.
The Menus
1.4.3
Coupling (AC/DC/Gnd) 3.1
Additional Buttons
3.1.1
The Numeric Buttons
1.5 Horizontal Adjustments 3.1.2
Menu Traces
1.5.1
TIME/DIVISION
3.1.3
Control
1.5.2
Aliases
3.1.4
Post Store
1.5.3
Position
1.5.4
Magnification 3.2
Control Master Menu
3.3
Status Menu
1.6 Vertical Adjustments 3.3.1
Mode
1.6.1
VOLTS/DIVISION
3.3.2
Max/Min
1.6.2
Position
3.3.3
V/Div
1.6.3
Variable/Uncalibrated
3.3.4
Probe set
1.6.4
Add
3.3.5
Timebase
3.3.6
Trigger
1.7 Manually Obtaining a Trace
1.8 Operating Hints
3.4
Display and Trigger Menu
1.8.1
Intensities too low
3.4.1
Probe ratio
1.8.2
Trace off the top or bottom
3.4.2
Max/Min
of screen
3.4.3
Dot Join
1.8.3
Trace not being acquired
3.4.4
Averaging
1.8.4
Trace unstable
3.4.5
Trig Pos'n
1.8.5
Trace has flat top or bottom
3.5
Display Intensity
2. Advanced Features
3.6
Reference Trace
2.1 Trigger Control
3.7
RS423 Interface Menu
2.1.1
Selecting Source and Coupling
3.7.1
RS423 Plot Connections
2.1.2
Level
3.7.2
RS423 Data Connections
2.1.3
Trigger Point (T)
2.1.4 Slope (+/-)
3.8
Special Functions Menu
2.1.5
Trigger Mode (Norm/Auto) 3.9
Post Store Master Menu
2.1.6
Trigger Delay
3.10 Save Trace Menu
3.11
Recall Memory Menu
2.2 Captu e Facilities r
2.2.1
3.12 Plot Menu
Trace Hold
2.2.2
S/Shot and Run
4.
Performance checking
2.2.3
Acquisition Status-AFTS 4.1
Risetime
4.2
Bandwidth
2.3 Display Modes
4.3
Trigger sensitivity
2.4 Cursor Measurements
4.4
Trigger bandwidth
2.4.1
Cursor and Datum Selection 4.5
Timebase calibration
2.4.2
The Cursor& Datum Lines 4.6
Vertical Calibration
2.4.3
Making Measurements 4.7
Max-Min (Alias Detector)

Contents
400 Series Operators Manual
5.
Waveform Processing Functions Figure List
5.1 Cursor Measurements
1.2a Single Function Buttons
5.1.1 Voltage and Time 1.2b The Toggles
5.1.2 Peak-Peak 1.2c Pressure Sensitive Buttons
5.1.3 Max-Min 1.3 Start-Up Display
5.1.4 Risetime (falltime) 1.4 Obtaining a trace
5.1.5 Overshoot (preshoot) 1.4.1 An AUTO SETUP Display
5.1.6 Pulse Width 1.5 Horizontal Controls
5.1.7 Frequency, Period, Duty Cycle 1.5.2 Alias Generation
5.1.8 RMS 1.6 Vertical Controls
5.1.9 Area 2.1 Trigger Controls
2.1.6 Trace Capture with Delay
5.2 Trace Manipulation
2.2 Capture Controls
5.2.1 Filter Frequency 2.4 The Cursor and Datum Line Controls
5.2.2 Filter Current Trace 2.4.2 The Cursor and Datum Lines
5.2.3 Invert Current Trace 2.5.5 Paper Loading
5.2.4 Integrate Signal 2.5.8a Relative Plot Positions
5.2.5 Integrate Current Trace 2.5.8b Plot Dimensions
3 Menu Overview
5.3 Trace arithmetic
3.1 Numeric Buttons
3.2 Control Master Menu
5.4 Persistence/Limits Testing
3.3 A Status Menu
5.4.1 Limits 3.4 A Display and Trigger Menu
5.4.2 Persistence 3.5 Display Intensity Menu
3.6 Reference Trace Menu
6.
Battery Unit Operation
3.7 An RS423 Interface Menu
3.7.1 400to Gould 6120 or HP7475 Connections
7.
Alphabetical Summary of controls
3.7.2a 400 to IBM-PC/XT Connections
3.7.2b 400 to IBM-PC/AT Connections
Appendix 1: Error Messages
3.8 Special Functions Menu
3.9 Post Storage Master Menu
Appendix 2: Specification
3.10 Save Trace Menu
3.11 Recall Trace Menu
Appendix 3: Remote DC operation of the DSO
3.12 Plot Menu
5.1a Cursor Measurements Menu
Appendix 4: Front and Back Pictures
5.1b Example of Calculations on trace
5.1.1 Voltage and Time Measurement
Service Facilities
5.1.2 Peak to Peak Measurement
5.1.3 Max-Min Measurement
5.1.4 Risetime Measurement
5.1.5 Overshoot Measurement
5.1.6 Pulse Width Measurement
5.1.7 Freq. Period and Duty Cycle Measurement
5.1.9 Area Measurement
5.2 Trace Manipulation Menu
5.4 Persistence/Limits Testing Menu
6 Battery Unit Interconnections
6.2 Battery Unit Front Panel Indicators
A2 400 Series Dimensions
A3.2 DC Power Connections
A4a Rear View
A4b RS423 Connections
A4c
Front Panel Controls

400 Operators Manual Introduction
I
n
t
ro
d
uc
ti
on
The Gould 400 series instruments are Digital Storage
Oscilloscopes (DSOs). They include all the features
expected of advanced modern oscilloscopes designed for
the professional engineer, whilst retaining the user-
friendliness essential for those learning to use such
instruments for the first time.
The 400 range consists of three basic models; the 400 the
420 and the 450. All versions can be fitted with a battery
unit which provides the instrument with a fully automatic
built in Nickel Cadmium battery and charger which
allows uninterrupted operation of the DSO in the event
of an AC supply failure and complete operation
independent of an AC supply.
Obtaining a trace is especially simple - just connect the
signal and press the Auto Setup button - the 400 does the
rest. Having obtained a trace, readily accessible datum
lines and a cursor make it easy to take automatic timing
and voltage measurements directly from the display. On
the 420 and 450 models, the waveform processing
function increases the power of the cursor measurements
in terms of both capture and post storage analysis and
measurement functions.
The innovative use of ergonomically designed pressure
sensitive push button controls provides a combination of
precision and flexibility for ease of operation.
More advanced features of the 400 series include a co
m
-
prehensive range of menu-controlled functions. For
example, the Display and Trigger menu operates features
such as the trigger delay and pre-trigger display
functions. The pre-trigger display function allows the
signal prior to the trigger point to be captured and
displayed.
Three complete traces can be stored for future use and
recalled to the display via the Save Trace and Recall
Trace menus respectively. With the built in battery back
up facility, these will be retained even when the
instrument is switched off.
In addition to the above features, the 420 and 450 instru-
ments have a built in 4 colour plotter and a battery
backed Real Time Clock. This provides a simple and
convenient method of obtaining permanent hard copy
plots of the screen display. The plots will contain the date
and time of acquisition together with the date and time of
plotting.
The 450 has all the features of the 420 and has a signal
bandwidth of 50MHz and an extra timebase range of
50ns/div.
N
umbers circled in the text refer to the controls shown
on the front panel picture in Appendix 3.

Getting Started 1.1-1.1.6 400 Series Operators Manual
1.1 Safety and Power Requirements
they should be removed only by suitably qualified personnel
for maintenance and repair purposes.
1.1.1 International Safety Warning
(as required for I.E.C. 348 Cat I)
This instrument has been designed and tested in accordance
with IEC publication 348, and has been supplied in a safe
condition. This manual contains information and warnings
which must be observed to keep the instrument in a safe
condition. The instrument should not be switched on if it is
damaged and it should not be used under wet conditions.
For the correct and safe use of this instrument it is essential that
both operating and service personnel follow generally accepted
safety procedures in addition to the safety precautions specified
in this manual.
Whenever it is likely that safety-protection has been impaired,
the instrument must be made inoperative and be secured against
any unintended operation. Qualified maintenance or repair
personnel should be informed. Safety protection is likely to be
impaired if, for example the instrument shows visible damage
or fails to perform the intended measurements correctly.
WARNING: Removing the covers may expose voltages in
excess of 8000V at the side of the display tube; these
may be present for up to one minute after the
instrument has been disconnected from the power
source.
1.1.4 Ventilation and Dust
The instrument relies on forced air cooling via a fan and
ventilation slots. Adequate ventilation can usually be achieved
by leaving a 75mm (3" gap) around the instrument.
The instrument should not be operated in dusty environments.
If the CRT filter requires cleaning it can be easily removed by
pressing in its right hand edge as shown by the moulded arrow.
1.1.5 Operating Temperatures
The instrument is designed to be operated in an environment
having an ambient temperature of between 0 and 50 degrees C,
(0 to 45 degrees if the battery unit is fitted) and to operate with
full accuracy between 15 and 35 degrees C.
Note: Direct sunlight, radiators and other heat sources
should be taken into account when assessing the ambient
temperature.
The instrument may occasionally be subjected to temperatures
between 0
and -10ºC without degradation of its safety.
1.1.2 Grounding
THE INSTRUMENT MUST BE GROUNDED.
AC
The instrument must be operated with a protective ground
connected via the yellow/green conductor of the supply cable.
This is connected to the instrument before the line and neutral
connections when the supply plug is inserted into the socket on
the back of the instrument. If the final connection to the supply
is made elsewhere, ensure that the ground connection is made
before line and neutral.
DC
If the unit is disconnected from the AC supply, and powered
from an isolated DC source or the internal battery unit, the unit
will not be grounded. Independent provision must be made to
maintain the case at a safe potential, by grounding the safety
ground terminal on the DSO rear panel. The safety ground
terminal is connected to the instrument case, to the ground of
the input signals (outer of the BNC connectors), and also
internally to the negative side of the DC supply.
1.1.6 Power and Frequency Requirements
The instrument uses less than 85V A (200V A if battery unit
fitted) and operates from line voltages of 90V to 130V, and
190V to 265V, at 45 to 400Hz. Under the extreme conditions of
90V and 45Hz, the instrument will still operate correctly even if
there is a half cycle dropout in the line supply.
The instrument may be powered from a direct current supply in
the range 12V to 33V. The unit cannot be damaged by applying
power to both inputs simultaneously.
Before connecting the instrument to the supply, ensure that the
rear panel AC supply voltage selectors are set to the appropriate
voltage.
Access to the voltage selector can only be made if the AC
supply connector is removed, and is by hinging open the panel
connector from its top edge. The selector barrel can then be
moved to the required setting. This same operation provides
access to the AC supply fuse, which must be changed to suit
the supply voltage as shown in table 1.1. 7.
The AC power connection is via a standard IEC, CEE 22
connector and the DC power input is via the supplied 0.25"
spade connector (Gould part No. 457839.) See appendix 4 for
polarity details.
WARNING: Any interruption of the protective ground
conductor inside or outside the instrument is likely to
make the instrument dangerous. Intentional
interruption is prohibited.
Signal connections to the instrument should be connected after
the ground connection is made and disconnected before the
ground connection is removed, i.e. the supply lead must be
connected whenever signal leads are connected.
1.1.3 Live Parts
The instrument should not be operated with covers removed.
The covers protect the user from live parts and

400 Operators Manual Getting Started
Figure 1.2a Single Function Buttons
Figure 1.2b The Toggles
Figure 1.2c The Pressure Sensitive Buttons

400 Series Operators Manual
Getting Started 1.1.7-1.4.1
1.3 Start-Up Display
When switched on with the POWER button (1) . the instrument
will go through its automatic self-calibration sequence and then
display information similar to that shown in Figure 1.3.
CAUTION: The negative DC terminal is connected to the
safety ground terminal and the instrument case.
Care should be taken to avoid ground loops when,
for example, the instrument is used in a vehicle and
powered by that vehicle's supply.
1.1.7 Fuse Requirements
The fuse arrangement shown in table 1.1. 7 must be followed,
and additionally in the UK, a 3A fuse (5A if the battery unit is
fitted) should be fitted in the line supply plug .
Su
pp
l
y
Slow Blow Goul
d
Su
gg
ested t
yp
es.
Voltage Fuse Rating Part No Manufacturer/Type No
IEC (ULlCSA) DSO
230V 0.5A (0.6A) 457452 BeswickrrDC488,
Littlefuse/239,
Schurter/FSP
115V lA (1.2A) 457454 BeswickrrDC488,
Littlefuse/239
Schurter/FSP
12VDC 5A (6A) 457979 HRC type
Beswick/S505,
Wickman 19181
BATTERY UNIT
230V lA (1.2A) 457454 BeswickrrDC488,
Littlefuse/239,
Schurter/FSP
115V 2A (2.5A) 457455 BeswickrrDC488,
Littlefuse/239,
Schurter/FS
P
Figure 1.3 Start
-
Up Displa
y
The trace is visible across the centre of the screen. At the top
will be the sensitivity of the two input channels and the
timebase speed. It any input is inactive, information for that
channel will not be displayed.
Users with no previous experience of a DSO will find that the
400 responds like a conventional Real Time Oscilloscope while
it is repetitively triggered, but in the absence of further valid
triggers, it retains the last trace for continuous display.
Table 1.1.7 Fuse rating
s
Note: For different DC voltages, the DC fuse rating multiplied
by the voltage used should equal60W. e.g. at 30V a 2A
fuse is required. For additional safety under extreme
fault conditions, the DC fuse
is a high rupture current
(HRC) type. This fuse should have a 1500A break
capacity.
1.4 Obtaining a Trace See Figure 1.4
1.4.1 AUTO SETUP
To display an input signal, connect it via either the CHI socket
(9) or the CH2 socket (12) and press AUTO SETUP (24) .
Assuming you've applied a regular signal, say a 2kHz sine-
wave with an amplitude of perhaps 5V peak to peak, it will
almost immediately be represented on the display. An example
is shown in Figure 1.4.1.
It the display is very dim or has completely disappeared see
section 1.8.1.
1.2 Using the Buttons see appendix 3
There are three types of buttons. The first type usually have
only one function: when pressed, that one function will be
activated e.g. AUTO SETUP (
24) . See Figure 1.2a.
The second type are toggles: each press of the button either
switches something on or off e.g. Add (10) , or selects the
next item in a sequence e.g. Off/On/lnv (13) . See Figure
1.2b.
AUTO SETUP will attempt to arrange the display so that two
to five complete cycles appear, with the amplitude set so
that the height of the trace is between two and five
screen divisions. Also, it selects Auto trigger to ensure
that the screen is frequently updated and a trace will be
visible.
The third type are Pressure Sensitive: the effect caused depends
upon how hard the button is pressed. For example, a gentle
press of a Pos'n (8) button will move the trace slowly. If the
button is pressed harder, the trace will move more quickly. See
Figure 1.2c. If signals are connected to both channels, the
highest amplitude takes priority.

Getting Started 1 .4.2-1 .5.1
400 Series Operators Manual
1.4.3 Coupling (AC/DC/Gnd) (14)
These buttons control the type of coupling between the input signal
and the instrument. DC is the most generally applicable, and
AUTO SETUP will normally set this control to DC, where
possible.
The input impedance is I M ohm in parallel with a capacitance of
28pF.
AC This is used to remove any DC component from input
signals. Suitable input signals (i.e. the bandwidth) are from
4Hz to 20MHz.
Gnd The input signal is internally disconnected from the inputs and
the amplifier grounded. A OV reference signal is displayed.
DC The input signal is directly coupled to the instrument so all
frequency components of the input signal will be displayed.
The bandwidth will be from DC to 20MHz.
Figure 1.4 Obtaining a Trace
1.5 Horizontal Adjustments
Figure
1.4.1
A
n AUTO SETUP Displa
y
Figure 1.5 Horizontal Control
s
1.4.2 Channel Selection (Off/On/lnv) (13)
A channel may be switched on or off with its Off/On/Inv button. If
the channel is on, its trace can be displayed in either normal or
inverted mode.
Off The channel is deactivated.
On The trace is a true representation of the input signal. Inv The
input signal is inverted before being displayed. If
there is any DC component in the signal this will also be
inverted and could cause the trace to disappear from the
screen. Such an unwanted DC component can be removed
by selecting AC coupling. Any vertical shift applied to the
trace is not inverted. The trigger point remains at the same
point on the waveform regardless of inversion.
1.5.1 TIME/DIVISION
TIME/DIV (33) These buttons control the sweep rate of the trace.
The timebase can be varied from 100ns/div to 50s/div in a I,
2, 5 sequence of values. The button marked 'ns' decreases
the time/div, the button marked 'sec' increases the time/div.
With a timebase of say 200/Ls, each horizontal screen division
represents 200/Ls worth of signal. The timebase is shown near the
top of the display - e.g. TB=200/Ls.
Assuming a 2kHz signal is applied as mentioned earlier, when the
timebase is set to 500ms/div, an interesting phenomenon may
appear: an 'alias'.