Racal Instruments 9901 Maintenance Manual page 18

I
i-
lid
I
y J
My
= =
Q
i
J
A
DATA OUTPUT
CONNECTIONS
AT Dafa and command
information
is
provided on a 28-way
edge
connector
accessible
via a removable cover on
the rear panel. The
facilities
and
pin connections are
listed in
Table
1
below. The
logic for
time base
and
function data
is
given
in
Tables 2
and
3.
TABLE
1
Data Output Socket
Pin
Facility
Pin
Facility
1
-5V
(nominal)
A
OV
2 +5V
(nominal)
B Overflow
(static
indication)
3 Key
Way
C
Key
Way
4
7
(BCD) D
T
(BCD)
5
s'
(BCD)
E 2 (BCD)
6
External
Hold
Input
F
1
0
kHz
Sync
.
7
External Reset Input H
Main Gate
8 Auto
J
Not
Used
9
c
Function
K
—
N
Z
Time
Base
10
b
* Information
L 7
>
Information
11 (See Table
2)
M
X
J
(See Table
3)
12 Ro
N
Not
Used
13
Hold/Reset
P
Schmitt
'B'
1
See
14
Not
Used
R
Schmitt
'A'
J
NOTE
1
NOTES:
1
.
Schmitt
A
and
Schmitt
'B'
outputs on
pins R
and
P
show
the
states of
d,c. channel Schmitt
triggers.
2. External Hold
Input
To extend
the
cycle time
the external hold
signal (logic
'0') must be applied
during the gate or hold time.
To
initiate
a
new
measurement
cycle
the
external hold must
go
'high' for not
less
than
200
ps.
3.
External Reset Input
To apply
external
reset the level at
pin
7
must go
to logic
'O'
for not
less
than
5 ms.
On
reverting
to
'1
'
level the display
resets
to 'all zeros'
and
a
new
measurement commences.
9901 Vol.2
Tech. Spec.
(7)