Gould OS4001 User Manual

054001

OUTPUT UNIT

Instruction Manual

-} GOULD ADVANCE

Telephone [phone]
Telegrams Attenuate Ilford
Telex 263785

SECTION 1

SECTION 2

SECTION

SECTION

Introduction

Specification

Operating Instructions

3

General

3.1
Chart recorder speed

3.2
Driving a chart recorder 5

3.3

The Read-out cycle 5

3.4

Remote start

3.5

Function Generation

3.6

3.7 Digital Outputs

Circuit Description

4

4.1 General

D-A Converter

4.2

Latches and latch control 9

4.3

4.4

X-ramp counter 9

4.5 Data Selector

4.6 Clock delay

10

3

SECTION 5

4

5

Maintenance
Fitting the 4001 to the OS4000

5.1

5.2 Access
Fault finding

5.3

Setting up Procedure

5.4

12
12
13
14
15

5
5

SECTION

Circuit Diagrams and Components

6

Schedules 17

5

SECTION
7
7

8

8

9

Fig. 1
Fig. 2
Fig. 3 Block diagram
Fig. 4

Fig. 5

9

Fig. 6
Fig. 7
Fig. 8

Guarantee and Service Facilities

7

ILLUSTRATIONS
Typical read-out cycle
Connections to back panel socket

Data Selector - mechanical

equivalent

Clock delay - timing diagram

Internal view of 4001
Fixing details
Circuit diagram

21

6
7
8

10
11
12
13
19

Introduction

The 400 I option is designed to be added to a standard
OS4000 Digital Storage Oscilloscope to enable the infor-
mation in store to be retransmitted in both analogue and
digital form. Two analogue outputs are provided, and
these are intended primarily to drive strip chart and X-V
recorders. Channel I and 2 signals are available simultan-
eously at a read-out rate which can be varied to suit the
chart recorder, with a slowest time of 200 seconds
representing the 10 division display. In addition, a
corresponding X-ramp signal is provided for X-Y recorder

use. The unit also incorporates relay contacts for pen lift
or chart motor control. There is a variable delay between

the closing of these contacts and the start of read out
which can be preset to allow a chart drive motor to
accelerate.

.A socket on the rear panel presents the output infor-

mation in digital form as two eight bit parallel signals for
Y and one ten bit parallel signal for the X ramp. Control
facilities for remote start and continuous readout are also
provided. The latter can be used for continuous
generation of a recorded transient or frequency shift of
recorded waveforms.

Specification

Section 2

ANALOGUE OUTPUTS Via B.N.C. connectors

Channels 1 and 2

Amplitude lOOmV per cm of screen height.

Bipolar with OV corresponding to
middle of screen

Accuracy Output voltage per cm of display±3%

Output to input voltage (ca!)

X Ramp

Amplitude

Time output accuracy of Y Channel outputs±1%
(Record to replay ratio)

Output Impedance CHI, CH2 and X-ramp

DIGITAL OUTPUTS Via back panel socket

Channels I and 2
X Ramp

Accuracy

lOOmV per cm of screen width.
Positive ramp resetting to OV
Output voltage/cm of display±J%
Output voltage/unit time recorded±3%

100H/0.IJ.lF

Continuous short circuit protected

All outputs true binary from open
collector T.T.L. buffers

8 bit parallel, negative logic

10 bit parallel, negative logic
Y Channel full scale=9cm of display±5%
X Ramp full scale=II.3cm of display ± 5%

±

3%

Remote continuous read-out by T.T.L. low or contact

closure to ground.

Delay between start command and
initiation of read-out cycle set by front

panel preset control from <20msec to

> I sec.

(lOJ.lsec. to lOsec. by internal component
change)

Front panel access via 4mm sockets to
isolated single pole contact which closes
from start command to end of read-out

cycle
Contact rating 200V D.C. 0.5 A D.C.

IOWD.C. Isolation 400V max.

OUTPUTS

Oocks I and 2

Negative T.T.L. pulses, 100nsec.

duration marking the change of
each digital word.

T.T.L. low, commencing at the end
of delay, for the duration of the
read-out cycle.

READ OUT RATE

Set on OS4000 time base range switch
Range 20sec/cm to
Read-out bandwidth D.C. - 16kHz (-3dB)

CONTROLS

Front panel start button to initiate single read-out cycle.
Remote start by T.T.L.low or contact closure to ground.

200J.ls/cm

DIMENSIONS 3.75cm extra height to OS4000

WEIGHT 570gm extra (l

ACCESSORIES 36 way plug Ampheno157-30360

%

Ib) to OS4000 approx.

2 x 4mm plugs
Handbook PN 36896

Operation

3.1

ANALOGUE OUTPUTS

The 4001 may be used to drive strip-chart, T-Y or X-V
recorders. Both Y channels are available simultaneously
for chart recorders with two pens. Alternatively, the two
channels may be reproduced sequentially on single pen
recorders. A synchronised X-ramp is available to drive
X-V recorders as Y-t. Alternatively, the CHI and CH2
outputs can drive an X-Y display directly.

The internal contacts can be used to control chart motor
and/or pen lift if required.

3.2

CHART RECORDER SPEED

The 4001 offers a very wide range of read-out rates to suit
the recorder being used. The rate should be chosen by
considering the following:

1) A slow read-out rate, while faithfully reproducing
the stored signal, will also show the discrete levels
in the output waveform, (there is no dot-joining on
the 4001 outputs). A faster read-out rate and chart
recorder speed will tend to smooth the output wave·
form.

2) If too high a read-out rate is chosen, the chart
recorder may be unable to follow any large ampli-
tude fast change of the signal. This is slew-rate
limitation of the recorder.
The optimum read out speed for any particular
stored waveform is thus the maximum at which the
chart recorder is capable of tracking the signal. This

may be determined by increasing the readout/chart
recorder speed each sweep until waveform degrad-
ation can be observed.
The bandwidth of the output amplifier is d.c. to

16kHz (-3d B) which is well above the limitation of
most chart recorders. However this limitation may
be reached if the output is required for other

purposes when the replay frequency is a function
of recorded waveform and replay rate.

(See Function Generator)

3.3

DRIVING A CHART RECORDER

1) Connect to the CHI, CH2 and X-ramp sockets as
reqUired. In single trace operation, the same signal
will be present at CHI and CH2 outputs.
Set the sensitivity of the chart recorder inputs to
accommodate±400rn V f.s. on CHI and CH2 and

o

to 1V on the X-ramp.

When the 4001 is not reading out, the CHI and 2

and the X-ramp outputs return to
V-channel output corresponds to mid-screen on the
OS4000 display and thus the chart recorder pen

should be set to mid-scale unless specifically

required otherwise.

The X-ramp moves positive fromOVand thus the

OV.

Ov on the

pen should be positioned to allow at least 1V
positive travel.

2) Connect, if required for remote start/pen lift.
NOTE: The relay contacts are unprotected and
inductive loads should be suppressed to stay within

the contact rating.

3) The delay time (from closing of relay contacts to
start of read-out) is set by a front panel screwdriver

preset. The minimum delay time of < 20rns is

sufficiently short for recorders for which no delay
is required. The preset control range allows the
delay time to be set to a maximum of 1 second but
this can be increased to approx. 10 sec. by increasing
the internal capacitor C80I to I5tlF.

4) Obtain the required trace on the OS4000 and

STORE or LOCK it. If the 50% hold facility is
being used, the trace stored by the 50% hold will
appear at the CH2 output, the other trace appearing
at CHI.

5) Set the required read-out rate on the timebase range
switch.

6) Press the start switch to initiate the read-out cycle.
Note the display is inhibited during read-out. At
slow read-out rates, this will result in a blank screen
for considerable periods. Similarly the OS4000 is
prevented from accepting new data into the store
during this period.

7) At the end of the read-out cycle, reset the timebase
range switch as required to record subsequent data.

3.4

THE READ-OUT CYCLE

Fig. 1 shows a typical read-out cycle. The cycle is

initiated by a negative edge on the start input produced

by the push button or by remote start (see section 3.5).

The relay contacts close within 0.5msec. of the start

command and the preset delay period is started. At the

end of this delay, the read-out is primed to start at T1

the end of the current display sweep on the 0S4000.
Period t3 has any value from 0 to I.2msec. depending

on when the button was pushed but is unlikely to be a
significant delay at chart recorder speeds. If required,
the read-out marker, available at the back panel socket
SK A.C. pin 2, can be connected to the chart recorder
event marker to indicate the exact start of read-out. At
the end of read-out, the relay contacts open again within

0.5ms and all analogue outputs return to

3.5

REMOTE START

The remote start input appears on contact 3 on the back
panel socket SK AC. Read-outs may be initiated by a
T.T.L.low on this contact or by connecting it to contact

4 which is logic earth. This action has the identical effect

to pushing the front panel button.

OV.

Operation

DELAY

OIP

START

COMMAND

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Section 3

SINGLE
TRACE

CLOCKS
1 AND 2

CHl AND
CH2 DATA

CHl AND CH2
ANALOGUE
OUTPUTS

CH'

ANALOGUE
OUTPUT

CH2
ANALOGUE
OUTPUT

X-RAMP
ANALOGUE
OUTPUT

'~', -- -- _I~

'0'

'1'

'0'

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'0' 1000 0000 '. . _

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..---- OUTPUTS HELD AT

_Ov II- ----

'1'

f- __

'0' LOW i~~ (LOW)

1000 0000 I

ALL OUTPUTS HELD---,~r-y-y--y-y ALL OUTPUTS CLEARED TO

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STEP 1023 :

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OUTPUTS CLEARED TO

1000 0000

90%-10%

FALL TIME

approx

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