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Model 11180A
20. This gives the ability to arbitrarily set the time at which
the 0th, 10th or 20th reading is completed. The next
reading received by the 11180A will be counted as the 1st,
11th or 21st. Each line has an edge triggered one-shot
consisting
of an inverter IC42, RC network and a 2-input
NAND gate IC41. In the case of the Preset 0 line, Rl 1 and
C6 form the RC time constant of the one-shot, and Rl 2 is a
pull-up resistor on the input to insure recharge of the time
constant. The output pulse is a 1
µs
low pulse. In the case
of the Preset 0 Trigger, it forces the 10, 20 and 40 Counter
flip-flops to the "O" state and sets the Units Address
Counter to a count of 1 through 134. At the same time, it
"sets" the Input Cycle Hold override flip-flop, IC20 pins 1
through 6.
4-39. JUMP.
4-40.
The Jump command stops an input or output cycle
in the middle and moves the 1l180A on to the next type of
cycle. In other words, if it stops on an input cycle, it would
begin on an output cycle; if it stops in the middle of an
output cycle, it would begin on an input cycle. A one-shot
on the Jump line produces a 1
µslow
pulse which
"sets"
the main Jump flip-flop consisting of IC3 l pins 1, 2, 4, 5
and 6 and IC32 pins 8, 9 and 10. When this flip-flop is
"set", it goes low at pin 8 of IC3 2. This low does 3 basic
things. First, it goes to the Storage Flag gating, IC23 pins 2
and 4 and prevents anymore data printing from taking place
if it is in on output cycle. Secondly, it goes to IC46 pin 3
and causes the light isolator Ll2 of Al to be turned on,
thus holding the mainframe from taking anymore readings
until allowed to later. Thirdly, it goes to IC38 pin 2 to
cause IC38 pin 12 to go high and allow the basic Timing
Generator to generate continuous timing pulses. The Jump
flip-flop is reset at IC32 pin 10 by the pulse from Ll9 of
the Tens Counter.
4-41. LIMITS.
4-42. The Storage limits are made by comparing the output
of the Tens Counter with the Limit 10, 20, 30 and 40 lines.
This is done by IC30. If the coincidence is met, the
comparator sends a command to pin 4 of the Jump
flip-flop, causing a normal jump command to stop the cycle
in the middle.
4-43. MEASUREMENT HOLD.
4-44. The Measurement Hold flip-flop is reset at the end of
each cycle if the Measurement Hold line is held low. If the
line is left open or floating high, the flip-flop cannot be
"set" and thus does not stop the 3480 from sampling. If
the line is held low, the flip-flop is reset at the proper time
and stops any further sampling by giving a Sample-Hold
Trigger Inhibit and Interface Hold.
4-45. Measurement Hold works as follows: If the line is
held low at the end of an output cycle, the l l l 80A will
Section IV
prevent all sampling by the 3480 (except from panel
manual trigger). When the line is released, or allowed to go
high for any period of time as short as 100 ns, the
Measurement Hold flip-flop will change state, allowing the
instrument to take one complete set of samples. This set is
determined by the limit chosen by the operator. It will then
begin an output cycle (unless Input Cycle Hold is being
used), and then if the line has been returned low before the
output cycle is completed, the flip-flop will again be "set"
and no sampling will take place until the operator desires it.
4-46. SCANNER CONTROL.
4-47. The Scanner Control Enable line allows the 3485A
Scanner to issue a Jump Command to the l l l 80A at the
end of a scan regardless of whether the storage limit has
been reached or not. IC31 pins 8, 9, 10, 12 and 13 on the
A2 board gates a pulse from the Scanner. This pulse is
allowed to reach the Jump flip-flop only on an input cycle
and not during a 3480 reading. This prevents lockup
conditions.
The pulse is generated by the Scanner Home
Flag going low, indicating the completion of a Scan .
4-48. There are other things that must be done in order to
make the Scanner work with the Storage Unit.
First,
in
Continuous Cycle, the Scanner goes through its Home
position in approximately 6
µs.
It must, therefore, be held
there while an output cycle is taking place. This is done by
a one-shot IC39 pins 10, 11
,
12, 13, 14 and 15 which resets
the Scanner at pin A on the J5B connector of the 3480
mainframe.
4-49. Also, if the Scanner Flag is low and a reading is taken
which is done every time that the Scanner is Home and the
Storage completes an output cycle, a single reading will be
taken which is the amplifier zero of the Scanner. It will be
printed out with a 00 notation in front of it. Oock Control
going high and the Scanner going Home (Scanner Flag low)
"sets" a flip-flop composed of IC35 pins 8 through 13 and
turns on Light Isolator Lil to override the Storage, turning
it off and acting as Isolated BCD to output this reading.
When this is done, it also sends a low
signal
to IC35 pin 2
on Al to stop this reading from being counted as a normal
reading.
This is done because more than one reading could
be taken if the Monitor function on the 3485A is used.
These readings are not counted; therefore, at the end of an
output cycle, it is not necessary to reset the counter IC32.
Reset is prevented by the Scanner Home Flag to the "clear"
input of IC39 pin 3 on Al.
4-50. The Scanner, if set at 10 channels, will complete the
10th channel reading; and the
Storage,
if also set to 10
channels, will stop the 3480 from sampling after the 10
channels. It will output the 10 channels and then allow the
Scanner to continue scanning, not knowing if the Scanner is
going to the Home position or to another reading. If it were
going to the Home position, a Jump command would be
given, forcing another output cycle although no new data
has been taken. This is prevented by the skip flip-flop IC34
pins 1 through 6 and the gate composed of IC34 pins 11
through 13. This flip-flop is "set" by the Panel Transfer line
4-3
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