Download Component List

How to open a local electronics
laboratory for remote access
Part 3
Providing components
and avoiding
destructive circuits
Outline
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
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Providing physical components for remote
experimenters
Assuring that it is only possible to activate
harmless circuits
Advanced experiments
Summary
Component handling and circuit
checking in a local laboratory
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
The instructor puts a set of components to be
used in the lab session on each workbench
During the session the students are
permitted to activate the sources in their
circuits only when the instructor have
checked that the circuits are harmless
Component handling and circuit
checking in the VISIR laboratory
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The lab staff installs component sets for the
lab sessions of a number of courses in the
switching matrix
A student can only use the set belonging to
the lab session s/he has logged in to
Checking if a desired circuit is harmless
before it is activated is made by a virtual
instructor using rules written by the teacher
Components used in lab exercises
are installed in the matix
Components
for the
students
Lab preparation in three steps
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The lab staff installs in the matrix the components
listed in the bill of materials of the lab instruction
manuals for the courses to be supported
The teachers creates rules for the virtual instructor
for each lab experiment
The teachers care for that the proper component set
are displayed in the component box on the top of the
virtual breadboard
The circuit is created in the matrix by
wiring on the virtual breadboard
Virtual Breadboard
Switching Matrix
XML, TCP/IP, port 2324
Client computer
side
Equipment
Server side
The procedure creating the circuit in the matrix mimics how the
student wires the circuit on the breadboard
Breadboard
Possible circuit
node
Matrix board for components
20 pin IC socket for
components with more than
two leads with wire holes
Node
connector
A component with two
leads
A group of 6 wire holes
forming a possible node
Double pole
relays
9
2017-05-23
Single pole
relays
ICBL
2008
Part of component board lay out
The nodes are
denoted A – I
and 0
The other
conductors in
the node bus are
denoted X1 – X6
and COM. They
are used for
power supply
connections and
for future
expansion
Relay number
Documentation of the matrix
configuration (Component List)
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All the components installed in the matrix are
recorded in a list called Component List
(component.list)
The sources are recorded in the list too
Component sets for several lab sessions can
be online if the matrix has a number
component boards
The matrix driver, Circuit Builder, uses the
component list to associate the nodes of an
installed component to relay numbers
An excerpt from the Component List
*This is comment
* Kort 4
OP_4_10:4_11:4_13
R_4_9
R_4_8
Pin number
1 2 3 4 5 67 8
NC B D G NC C F NC uA741
AB
1.6k
BC
1.6k
The text in red is not a part
of the list. It only shows the
pin order for components
with more than two leads.
NC means not connected.
These three components
are installed on board 4
Board number
DMM and oscilloscope
connections possiblilites


The DMM board has two inputs, one for
voltage or resistance measurements an one
for current measurements. Either of these
inputs can be connected to any two of the
nodes A – I or 0 for floating measurements
The ground terminal of both channels of the
oscilloscope are hardwired to node 0. The
other terminals can be connected to any of
the nodes A – I or 0
DMM, oscilloscope and sources
connections
DMM
board
Osc.
board
Source
board
Source connections possibilities

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The function generator can connect to
node A. The low terminal is hardwired
to node 0
The dual floating power supply can
connect to X2, X3. The common
terminal is hardwired to COM
The non floating power supply can
connect to X1. The low terminal is hard
wired to node 0
The number of the source board is
always 24
The source connections are listed in
the Component List
Excerpt from the Component List:
* Power supply
* Board 24 is the source board
VDC+25V_24_4:4_5
F
VDC+25V_24_4:4_3
D
VDC-25V_24_5:4_4
G
VDC+6V_24_3:4_7
A
VDCCOM_24_2
0
* Function generator
VFGENA_24_1
A
A
0
B
COM
C
X1
D
X2
E
X3
F
X4
G
Circuit created if all installed
components were connected
Teacher preparations
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

All components required in a certain lab
session must be online
It must be possible to connect them so that
the circuits in the lab assignments can be
wired.
It should also be possible to do harmless
wiring mistakes
Means to avoid destructive circuits
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
It is possible to set the maximum voltage or
maximum current permitted to output from
the sources
The impedance levels in the loops permitted
to create can be controlled
The teacher describes the rules in Max
Lists listing all connections permitted
VFGENA_1
VDC+25V_1
VDC-25V_2
VDCCOM_1
OP_1
R_R1
R_R2
R_R3
R_R4
R_R5
R_R6
R_R7
R_R8
JUMPERLEAD_S1
JUMPERLEAD_S2
JUMPERLEAD_S3
JUMPERLEAD_S4
JUMPERLEAD_S5
A0
max:5
F
vmax:15 imax:0.5
G
vmax:-15 imax:0.5
0
nc1 B D G nc5 C F nc8
uA741
AB
1k
AB
1.6k
AB
10k
BC
1k
BC
1.6k
BC
10k
0B
1k
0B
10k
AB
For example, omit the last
AD
line if the student would not
BC
be allowed to short circuit
0D
the op. amp. output.
0C
A special virtual instructor rule for
current measurements using the DMM

The DMM in current measurement mode are
low impedance and must only replace a
jumper lead
If you, for example, want to
measure the short cicuit
current of the op. amp. this
jumper lead must be
installed
Advanced usage
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The workbench can be used to probe a
printed circuit board or other ready-made
circuit with up to 10 test points
It is also possible to include components
from the component box and to use the
power supplies
The teacher preparations are the same. The
fixed circuit can be displayed in the
component box as an IC chip already
available in the component library
Example of simple a fixed circuit
defined as a 16 pin IC
Connecting the fixed circuit on the
breadboard to the matrix
Entering the circuit into the
Component List
OP_2_8:2_9:2_10
R_1_2
R_2_2
R_1_9
R_2_11
R_1_1
nc1 A nc3 nc4 G nc6 nc7 nc8 nc9 C nc11 nc12 F D B nc16
BC
1.6k
BC
10k
BC
1k
BC
120k
BC
4.02k
int1
Creating a Max List
VFGENA_1
VDC+25V_1
VDC-25V_2
VDCCOM_1
OP_2_8:2_9:2_10
R_R1
R_R2
R_R3
R_R4
R_R5
A
max:5
F
vmax:15 imax:0.5
G
vmax:-15 imax:0.5
0
nc1 A nc3 nc4 G nc6 nc7 nc8 nc9 C nc11 nc12 F D B nc16 int1
BC
1.6k
BC
10k
BC
1k
BC
120k
BC
4.02k
Displaying the circuit and the extra
components in the Component Box
A new option displaying the fixed
circuit will be added
Part three summary
Summary part 1 - 3
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The VISIR laboratory is an enhancement of
the local laboratory
The software representing almost 20 manyears of work is published and you are
invited to join the VISIR group and contribute
to the further development
The goal is producing engineers who have a
solid and documented experience of
laboratory work without increased cost per
student for universities