Model 5340A
Theory of Operation
4
-
283. A31
-
5
Volt
Regulator Assembly,
05340
-
60024
4
-
284. The
-
5 volt regulator assembly (Figure 8
-
34) consists of two supplies, one for the RF
circuits (
-
5V) in the 5340A and the other for the digital circuits (
-
DG).
The supply for the RF
circuits provides about 190 milliamperes and the digital supply provides approximately 1.1
amperes. The RF supply consists of a preregulator
A31Q1, A3lQ2, A31Q3, and A31CR1. A31Q8
is
the series pass transistor and A31Q4 serves as the regulator driver. The circuit
is
similar to the
-
15
volt regulator previously described. A31R17 sets the current limit point and A31R13 and
A31R14 determine the current foldback characteristics. The regulator for the digital circuits
consists of
A31U2, A31Q6, A31Q7, and Q1 which
is
mounted on the rear panel. Connection to
Q1
is made via the power supply motherboard A30. This regulator
is
similar to the
-
5 volt
regulator previously discussed except that no preregulator
is
used.
4
-
285. A34 Theory
of
Operation, 05340
-
60067 (Part
of
Option
011)
4
-
286. There are two basic modes of remote operation for the 5340A, they are TALK and LISTEN.
The three wire handshake must occur before the instrument can function in either mode.
A35S6 is
the “Talk Always
-
Addressable” switch. In the “Talk Always” mode, A35S6 keeps the talk flip
-
flop (U7) in the set condition. This allows the 5340A to communicate with
a
simple listener that
doesn’t have addressing capability. When
A35S6
is
in the “Addressable” position, the instrument
can be either
a
talker or listener. A low on IFC
is
a
direct clear, which resets U6 and U7.
4
-
287.
Talk
Mode
4-288. In the first sequence of the talk mode, the 5340A is addressed to talk. At this time ATN is
Low and the controller sends data via DIOl through
DI07. Switches A35S1 through A35S5
establish the 5
-
bit binary code which
is
an arbitrarily designated address of the 5340A. U14 com
-
pares this code to the data on lines DIOl through D105 and outputs
a
high when coincidence oc
-
curs. D106 and D107 carry the information which determines whether the instrument will func
-
tion
as a
talker or listener, this information
is
decoded by U6 and U7. The controller set DAV Low,
this signal is delayed by R4, C2, and R5, C3 which allow transients to die down. As
C3
charges
through R5,
UlD(11) will remain high. This enables U5A to provide the clock pulse for U6 and
U7. U5A also receives the IFC signal which must be high. ATN low will enable the RFD driver
UlOC and the DAC driver U19B. RFD will
go
low and DAC will go high, completing the three
wire handshake. (See Section
I1 for
a
more detailed explanation of the handshake). When U5A
clocks U6 or U7, only one will set. When Talk Flip
-
Flop U7
is
set, UllB(6) goes high enabling the
DIOl through D107 drivers UZA, B, C,
D,
U3A, B, C, D, and DAV driver U4D. UllB(6) will also
enable the RFD and DAC listeners
U13C, D. U13C provides the qualifier for test
#3
of
the pro
-
gram (HRFD
?)
and U13D provides the qualifier for test #10 (HDAC
?).
4
-
289. The second sequence of the Talk Mode is data outputting. After handshaking, the con
-
troller sets ATN high to disable the RFD and DAC gates (UlOB,C). The instrument can now out
-
put measurements
it
has taken via the DIOl through D107 drivers. SRQ (Service Request)
is
an
output driven low by
UlOD when the instrument has been programmed to wait in the output
phase of it’s operating cycle until addressed to output.
4
-
290. Listen Mode
4
-
291. In the first sequence of the listen mode, the 5340A is addressed to listen.
It
is identical to
the address sequence of ,the ,talk mode, with the exception that command on the DIOl through
D107 lines now tells the instrument to listen. U6
is
set and U5B(8) goes low for the duration of
DAV’s delay. U5B(8) genel;a es the LOAD signal.
4
-
292. The second seqpence
is
listening. UllC(8) enables the RFD and DAC drivers (UlOB,C) to
allow the instrument in
this
mode of operation to have control of these lines. The DAV driver (U4D)
is disabled. At this point in the sequence, the instrument
is
ready to accept data.
IF
4)
.
4
-
54
To Next Page
Loading...
Need help?
General
