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Items relevant to "Mains Power-Up Sequencer, part two":
|
Mains Power-Up Sequencer, part 2
Part 2 of John Clarke’s
Mains
Power-Up
Sequencer
This Sequencer solves problems that can occur when
switching on multiple mains-powered devices, like circuit
breakers tripping or loud thumps from speakers. It can also be
used as a master/slave power-saving solution. The Sequencer can handle
up to four devices but multiple units can be chained to handle 8, 12 or more.
T
he Sequencer can switch on one
to four (or more) devices in sequence, with an adjustable delay
between each power-on. It can also
switch them off in sequence, either in
the same order as they were switched
on or in the reverse order.
It can be configured to start to switch
on the devices in one of three ways:
immediately when power is applied
to it, when the appliance plugged into
the first outlet starts to draw power (in
which case the first outlet is always
on), or when a separate, isolated mains
supply comes online.
That last feature can join multiple
Sequencers to control more than four
devices. It can even allow you to switch
on devices in sequence across multiple
mains phases (eg, if you have a big lab
full of equipment).
In last month’s first article, we described all its features and how the
circuit works. Now we pick up where
we left off and move on to building it,
followed by testing and configuration.
Construction
Most of the Mains Power-Up Sequencer’s parts are assembled onto
a double-sided PCB coded 10108231
that measures 203 × 134mm. The
completed assembly is housed in an
ABS or polycarbonate plastic IP65
sealed enclosure measuring 222 ×
146 × 55mm.
Practical Electronics | March | 2025
Figs.5 & 6 show where all the components go on the circuit board.
You will not fill the entire PCB with
components when building the Mains
Power-Up Sequencer.
Typically, you would only install
the Current Detection section or the
Mains Input Detection section, but
not both. Or you could decide not to
use either, in which case none of those
parts are needed. The parts list last
month separated out the parts for the
optional sections.
The OUT1 channel must always
be installed, but note that there are a
couple of component value changes
in that section depending on whether
Current Detection is installed.
Additionally, if Current Detection is
not used, the two pads for CON7 must
be connected using a short length of
10A mains-rated wire.
Before construction, you will need
to decide on how many outlets you
will install. The PCB is initially set for
four outlets with the RA0 and RA1 pins
Warning: Mains Voltage
All circuitry within the Mains
Sequencer operates at Line
(mains) voltages. It would be an
electrocution hazard if built incorrectly or used with the lid open.
Only build this if you are fully experienced in building mains projects.
on IC9 tied to the 0V supply by short
tracks on the underside of the PCB.
To change this, the bottom layer
tracks right next to the RA0 and/or
RA1 pads will need to be cut (eg, using
a sharp hobby knife) and then those
pad(s) soldered to the small adjacent
pads on the top layer that connect to
+5.1V.
Refer to Table 1 to see which need
to be changed for one, two or three
outlets. If you can’t get the solder to
reach across the gap, use a short length
of component lead offcut.
Ensure you’ve properly isolated the
pads before soldering them to those
top pads, or you could short out the
5.1V supply (which will prevent the
unit from working but shouldn’t blow
anything up).
Circuit sections
The Mains Power-Up Sequencer
PCB screen printing separates the four
mains output circuitry sections (OUT1
to OUT4) using lines to delineate each
channel. The Current Detection and
Mains Input Detection sections are
also marked on the screen printing
and in Fig.5, so it is easy to see where
the components associated with each
section are located.
Before construction, decide which
sections you need using the information above. You can then start by
installing the smaller ¼W resistors.
59
Constructional Project
They have colour-coded bands indicating the values (shown in the
parts list last month), but it’s best to
use a digital multimeter (DMM) to
check each resistor before soldering
it in place.
Zener diodes ZD1 and ZD2 (if used)
and TVS1 (if used) can also be installed
now, taking care to orientate the zener
diodes correctly. TVS1 can go in either
way around.
Mount the ICs now, including the
opto-couplers, taking care to get the
correct IC in each place and with the
proper orientation. We used sockets
for IC9 and IC10, although you could
solder them directly to the PCB, assuming that IC9 has already been programmed. The opto-couplers (IC1-IC8
and IC11) are not all the same, so don’t
get them mixed up.
Note that on the PCB, pin 5 of the
IL410/4108 and the IL420/4208 have
only a tiny pad for an increased separation distance between the internal
Triac pins located at pins 4 and 6.
Those pins are not connected to the
rest of the circuit but you can solder
them if you want to.
The Triacs can be mounted now.
There are a few different ways to do
this. One is to smear a thin layer of flux
paste onto the large pad, then position
the device on the PCB and solder one
of the small leads. Check its alignment
and, if it’s OK, solder the other one.
Otherwise, reheat the initial joint and
nudge it into position first.
Finally, turn up your iron and feed
solder slowly into the large tab, as
Table 1 – number of outlets
RA1 (pin 18)
RA0 (pin 19)
# outlets
0V (bot)
GND (bot)
4 (default)
0V (bot)
5.1V (top)
3
5.1V (top)
GND (bot)
2
5.1V (top)
5.1V (top)
1
it will take a while to melt. Once it
gets hot enough, solder all along the
exposed portion of the tab. The flux
paste underneath will pull solder
under the tab and solder it to the circuit board.
Alternatively, it is possible to tin
both the pad and the tab of the device,
clamp them together while heating
the tab and feeding in more solder to
reflow them together, then solder the
two smaller pins.
Bridge rectifiers BR1 (and BR2 if
used) can now be mounted. These components must be correctly orientated
with the + lead inserted into the position marked with a + and seated close
to the PCB before soldering.
The 1W resistors can be fitted now.
Ensure the correct values are used and
note that for the OUT1 channel, R1 is
470W 1W when the Current Detection
components are installed or 330W 1W
when the Current Detection circuitry
is not installed.
There are 1MW resistors under the
relays that are inserted from the underside of the PCB, as shown in Fig.6.
Solder these in place
Before soldering the inductors,
they should be secured to the PCB
using cable ties.
60
and cut the leads flush with the top of
the PCB. Then mount the 1kW 5W resistor with a gap of about 1mm from
the PCB, to allow air to circulate.
Next, fit the capacitors, of which
there are three types: the mains X2rated capacitors, electrolytic capacitors, and MKT polyester types. The
electrolytic capacitors need to be orientated correctly since they are polarised, while the others can be installed
either way around.
For the OUT1 channel, C1 is 220nF
X2 when the Current Detection components are installed or 10nF X2 when
they are not installed. We have provided for the different sizes and lead
spacing on the PCB.
Next, install potentiometer VR1
and the three toggle switches S1-S3.
Then, mount the current transformer,
T1, if used.
Winding inductors L1-L4
It’s much easier to mount inductors L1 to L4 before the relays. These
are wound using a 500mm length of
1.25mm diameter enamelled copper
wire, with 10 turns evenly spread
around the powdered iron toroid. Strip
the insulation back by 1mm at each end
of the wire using a sharp craft knife,
insert the wire ends into the holes allocated and solder them in place from
the top side of the PCB.
Each inductor is supported using
a 200mm-long cable tie that loops
through the toroid and then through
the slotted holes in the PCB. It’s
best to tighten and trim the cable
ties before soldering the leads.
Make sure the solder adheres
to the bare copper; it won’t
make electrical contact if you
haven’t fully stripped back
the enamel.
The relays can now be
mounted, followed by the
sockets for the two-way
terminal blocks. They
must be inserted so the
plug-in screw connectors are orientated correctly, with the
screw head access positioned toward the
top edge of the PCB (left
side, as shown in Fig.5). The easiest way to ensure this is to plug the
screw terminals into the sockets before
inserting them into the PCB.
The LEDs are mounted above the
PCB, with the leads bent by 90° 4mm
Practical Electronics | March | 2025
Mains Power-Up Sequencer, part 2
Fig.5: the PCB is divided
into sections by lines. All
components outside the
boxed sections should be
fitted, along with the OUT1
section and however many
other outputs you need.
Depending on how you
plan to use it, you can also
add either the Mains Input
Detection (‘daisy-chain’)
components or the Current
Detection components
(including T1), but not both.
Fig.6: the only components
you need to fit on the
underside of the PCB are
these four 1MW resistors
underneath the relays. You
can omit those from any
output sections that are
not being populated. This
diagram is shown at 70% of
actual size.
from the rear of the LED, so they sit
horizontally. First, cover each lead with
a 20mm length of 1mm diameter heatshrink tubing. Then shrink the tubing
with a hot air gun and bend the leads,
ensuring that the anode (longer lead)
will be orientated correctly with the
LEDs bent (anodes facing to the top
in Fig.5).
The LEDs stand 20mm above the
Practical Electronics | March | 2025
PCB when measured from the top surface of the PCB to the LED centreline.
Case preparation
Before attaching the PCB, the IEC
connector cutouts must be made in
the side of the enclosure. You will
also need to drill holes in the lid for
the GPO sockets and in the enclosure
side for the LED indicators. The re-
quired holes are shown in Fig.7. It
can be downloaded as a PDF from our
website at 100% scale and printed at
actual size to use as a template.
Don’t make the holes in the lid just
yet as there are some options there,
which we’ll get to shortly.
Additionally, the two plastic standoffs (not the ones with brass tapped
inserts) that would be beneath the
61
Constructional Project
28.5
20
A
31
A
25
15.5
A
A
45.5
A
A
CUTOUTS
FOR IEC
CONNECTORS
A
36
(Base)
28.6
A
END OF CASE
(145 x 41mm)
A
15.5
C
15.5
C
50
45
A
TOP LID (145 x 221mm)
48
20
HOLES A: 4.5mm DIAMETER
HOLES B : 6.5mm DIAMETER
HOLES C: 50mm DIAMETER
ALL SHOWN HERE
AT 50% ACTUAL SIZE
ALL DIMENSIONS IN MILLIMETRES
C
45.5
95
OPTIONAL
MAINS
DETECT
INPUT
21.5
50
C
16
27
36
A
SIDE OF CASE (221 x 41mm)
OUT4 components on the PCB need
to be shortened using a large drill to
allow clearance for soldered joints
under the PCB.
Wiring
You can install the mains outlets in
one of two ways. One way (as in our
prototype) is to use surface-mounting
GPOs on the lid of the enclosure, as
shown in Fig.8.
Alternatively, you can use inline
mains sockets and mains leads (possibly cut from extension cords), held
A
48
48
10
10
10
10
B
B
B
B
32
53
B
Fig.7: here are
where the holes/
cutouts are made
in the case. The
Mains Detect Input
IEC socket hole
and the adjacent
screw holes are
only needed if
you’re using that
feature. If you
aren’t planning to
fit the GPOs to the
lid, don’t make any
holes in the lid;
you can mount the
grommets on the
opposite side of the
case to the LEDs.
The mains socket
holes are for the
MK Electric sockets
in the parts list last
month; they will
need to be adjusted
for other sockets.
(Base)
in place using cord grip grommets on
the side of the enclosure, as shown in
Fig.9. In this case, the Earth wires are
attached to an M4 bolt on the side of
the enclosure.
We provide cutout positions for the
GPO sockets in Fig.7 since they need to
be positioned on the lid so they don’t
foul PCB components underneath.
We haven’t provided drilling details
for the alternative method using the
cord grip grommets as the positioning
is not so critical.
However, the cutout shape for
cordgrip grommets is important as it
needs to be made so the grommet fits
snugly when the cord is captured, so
the lead cannot be pulled out from the
grommet. The cutout shape is essentially an elongated circular hole.
Cable glands could be used instead
of cordgrip grommets. In that case, it
is essential to secure the gland nut so
that the mains cable cannot be pulled
out. This can be done by coating the
gland threads with superglue before
tightening the nut to secure the mains
cable lead.
The LEDs are inserted into 16kV-rated bezels mounted on the side of the case to prevent shock hazards; how to mount the
bezels is shown in the inset photo. The switches and potentiometers are used to adjust the sequencing settings.
62
Practical Electronics | March | 2025
Mains Power-Up Sequencer, part 2
COVER EXPOSED
LIVE BUSBAR
WITH NEUTRAL
CURE SILICONE
OUT1
OUT4
N CURRENT
DETECT
MASTER
C ON 7
OUTPUT1
OUTPUT2
OUTPUT3
N
L
N
L
CON4
N
L
+
+
COIL
COIL
COIL
COIL
RLY4
RT334730
RLY3
RT334730
RLY2
RT334730
RLY1
RT334730
N
L
OUTPUT4
(DAISY
CHAIN
OUT)
CON3
CON2
CON1
BR1
W04
ZD1 5.1V
~
1MW 1W
–
~
1MW 1W
CON6
L
1kW 5W
IEC CONNECTOR
OUT3
OUT2
MAINS IN
470nF X2
10kW
330W 1W
10nF X2
330W 1W
TRIAC3
300W
330W 1W
10nF X2
330W 1W
TRIAC4
300W
330W 1W
10nF X2
330W 1W
10nF X2
330W 1W
**220nF X2
IC5
IC6
IC7
IC8
IL4108
IL4208
IL4108
IL4208
IL4108
680W
IL4208
IL4108
IL4208
RA1
RA0
NON-DETECT
A
OUT3
~
+
–
~
SWITCH
OFF
SWITCH
ON
100nF
LED4
A
OUT2
OUT1
S3
VR1 10kW
START RATE
UP
DELAY
NO DELAY
LED3
A
A
POWER
CURRENT/DAISY
CHAIN DETECT
S1
IC9 PIC16F1459
LED2
LED5
1kW 1W
10mF
TP 5.1V
10mF
LED1
10kW
IC11
4N25
1.5kW
10kW
100kW
4.7kW
ZD2 12V
CON9
BR2
W04
100nF
TP 0V
SILICON CHIP
680W
680W
230V AC
1MW 1W
750W
IC4
750W
IC3
750W
10mF
10mF
ALL PARTS AT
IC2
680W
CAUTION!
IC1
750W
IEC CONNECTOR
MCP6272
IC10
TRIAC2
300W
Cable tie L4
1kW 1W
18kW
TRIAC1
300W
470W 1W**
10nF X2
Cable tie L3
1kW 1W
CON8
IF CURRENT
DETECT NOT USED
10nF X2
Cable tie L2
1kW 1W
30kW
10kW
10nF X2
L4
L3
L2
**10nF X2 & Cable tie L1
330W 1W
CURRENT DETECTION
COMPONENTS
P4KE15A
20kW
2.2kW
15kW
COVER ANY
EXPOSED
TERMINALS WITH
HEATSHRINK
L1
TVS1
1kW 1W
NYLON
SCREWS
SHOULD
BE USED
T1
AC1010
1000mF
CON5
A
S2
OUT4
COVER LED LEADS
IN HEATSHRINK TUBING
(SHOWN HERE AT 50% FULL SIZE)
Fig.8: the wiring for the GPO version, which is what we built. Use 10A mainsrated wire with the correct colours for all connections, although the optional
Mains Detect Input wiring can use 10A or 7.5A mains-rated wire. Don’t skip the
cable ties as they have an important safety function.
OUT1
NOTE:
USE 10A MAINS WIRE EXCEPT
FOR CON8 TO CON9, WHERE
7.5A WIRE CAN BE USED.
OUT2
OUT3
OUT4
CORD GRIP
CLAMPS
M4 SCREW WITH
M4 NUT & STAR
LOCKWASHER
CRIMP EYELETS
COVER EXPOSED
LIVE BUSBAR
WITH NEUTRAL
CURE SILICONE
MAINS IN
A
N CURRENT
DETECT
MASTER
1kW 5W
CON7
OUTPUT2
OUTPUT3
N
L
N
L
N
L
OUTPUT4
CON4
N
L
+
+
COIL
COIL
COIL
RLY4
RT334730
RLY3
RT334730
RLY2
RT334730
RLY1
RT334730
(DAISY
CHAIN
OUT)
CON3
CON2
CON1
COIL
–
~
OUTPUT1
BR1
W04
ZD1 5.1V
~
1MW 1W
IEC CONNECTOR
1MW 1W
CON6
470nF X2
10kW
18kW
470W 1W**
10nF X2
330W 1W
TRIAC2
300W
330W 1W
TRIAC3
300W
330W 1W
10nF X2
330W 1W
10nF X2
Cable tie L3
10nF X2
330W 1W
Cable tie L4
TRIAC4
300W
330W 1W
10nF X2
330W 1W
**220nF X2
IC7
IC8
680W
IL4108
IL4208
NON-DETECT
230V AC
A
OUT3
A
OUT4
~
+
–
~
S3
100nF
A
OUT2
NO DELAY
LED4
A
OUT1
LED3
A
POWER
IC9 PIC16F1459
LED2
(SHOWN HERE AT 50% FULL SIZE)
LED5
1kW 1W
10mF
LED1
10mF
TP 5.1V
10kW
1.5kW
10kW
IC11
4N25
100kW
4.7kW
ZD2 12V
22nF X2
BR2
W04
CURRENT/DAISY
CHAIN DETECT
S1
SWITCH
OFF
SWITCH
ON
TP 0V
SILICON CHIP
680W
IC6
IL4208
750W
IC5
IL4108
750W
IC4
IL4208
100nF
IC3
IL4108
680W
IC2
IL4208
750W
IC1
IL4108
680W
10mF
10mF
ALL PARTS AT
750W
CAUTION!
1MW 1W
COVER ANY
EXPOSED
TERMINALS WITH
HEATSHRINK
300W
10nF X2
Cable tie L2
RA1
RA0
MCP6272
IC10
10nF X2
TRIAC1
1kW 1W
15kW
CO N 8
**10nF X2 & Cable tie L1
330W 1W
IF CURRENT
DETECT NOT USED
L4
L3
L2
1kW 1W
10kW
L1
1kW 1W
30kW
CURRENT DETECTION
COMPONENTS
20kW
2.2kW
P4KE15A
IEC CONNECTOR
TVS1
1kW 1W
NYLON
SCREWS
SHOULD
BE USED
T1
AC1010
1000mF
CO N 5
CON9
Practical Electronics | March | 2025
NOTES:
USE 10A MAINS WIRE EXCEPT
FOR CON8 TO CON9, WHERE
7.5A WIRE CAN BE USED.
ALSO EARTH LEAD SHOULD BE
ONE CONTINUOUS LENGTH
WITH INSULATION REMOVED
AT EACH GPO EARTH
CONNECTION.
22nF X2
The large cutouts for the mains
GPO sockets and IEC connectors can
be made by drilling a series of small
holes around the inside perimeter,
knocking out the centre piece and filing
the outline to a smooth finish. Other
methods include using a hole raw or
speed bore drill to remove most of the
inner area and then filing the rest to
the shape required.
Once the drilling and filing are complete, install the IEC connector(s). The
PCB can then be placed inside the case,
and the LEDs inserted into the bezels
as you drop the PCB into the enclosure. Then secure the PCB to the base
of the enclosure with 6mm-long M3
machine screws into the case’s integral brass inserts.
We specify Cliplite bezels specifically since they cover the LEDs
and are rated to withstand 16kV, so
they protect against a possible shock
hazard should the LEDs fail. Using
exposed LEDs at mains potential
could be an electric shock hazard.
Most 5mm LEDs don’t specify the
insulation capability of the package
between the LED dome and the LED
die inside. So use the bezels specified to ensure safety.
The IEC connector must be secured
using countersunk 10mm Nylon M3
screws, although you can use metal
nuts. The Nylon screws are essential
as they avoid the possibility of the
screws becoming live (at mains voltage) should a mains wire inside the
enclosure come adrift and contact a
screw holding the IEC connector.
Before attaching the mains GPO outlets and LED indicators, you can download and print out the front panel label
shown in Fig.10. Details on making a
front panel label are at siliconchip.au/
Help/FrontPanels
The download includes two versions
of the front panel. One front panel version does not have labelling for the
Mains Detect Input IEC connector if
you haven’t installed it.
All wiring must be run as shown
in either Fig.8 or Fig.9, using mainsrated cable. Be sure to use 10A wire
(7.5A is OK for the Mains Detect Input
wiring). The brown wire must be used
for the Active wiring, blue for Neutral and green/yellow striped for the
Earth wiring.
Note again that if you are not installing the Current Detection, then the two
pads for CON7 need to be joined using
10A mains wire (ideally brown).
S2
VR1 10kW
START RATE
UP
DELAY
COVER LED LEADS
IN HEATSHRINK TUBING
Fig.9: the wiring for the non-GPO version is similar to that shown in Fig.8 but
the Earth wires are terminated slightly differently. The output cables can be
made either by connecting mains flex to individual line sockets, or by cutting
the plug ends off 10A extension cords.
63
Constructional Project
OUT1
Testing
Mains Power Input
Fuse 10A
Fig.10: the lid label indicates
which inputs and outputs
have which function, while
the side label shows what each
LED means. There’s another
version of the label that you
can download from our website
without the text for the Mains
Detect Input if you aren’t using
that feature.
64
Mains Detect Input
Fuse 1A
SILICON CHIP
OUT2
OUT3
Mains
Power-Up
Sequencer
OUT4
For the lid-mounted GPOs, the
Earth wire from the IEC socket must
go straight to the first GPO Earth terminal, then to the second and so on
as a single length of wire. To do that,
strip the insulation off a single piece
of wire at each connection point.
Take great care when making the connections to the mains sockets (GPOs).
In particular, be sure to run the leads
to their correct terminals. The GPO
sockets will have the A, N and E clearly labelled, although Active might be
marked with an L (Live) instead of an
A. Do the screws up tightly so the leads
are held securely. Similarly, ensure
that the wires to the two-way screw
terminals are firmly secured.
For the version without GPOs, the
Earths are connected to crimp eyelets
that are then all attached to the M4
Earth bolt, which is secured to the case
using a star washer and nut.
Be sure to insulate all the Active
and Neutral connections on the IEC
connectors with heatshrink tubing
for safety, and cable tie the wires as
shown to prevent any broken wires
from coming adrift. Use 5mm diameter heatshrink for the wires to the IEC
connector.
Secure the Active and Neutral leads
together using cable ties. Also, use
neutral-cure silicone sealant (eg, roof
& gutter silicone) to cover the Active
bus piece that connects the Active pin
to the fuse at the rear of the IEC connector. That bus is live, and there is
no need to leave it exposed.
Power 1
2
3
4
Always attach the lid using at least
two screws at diagonally opposite locations before switching on the power.
All the circuitry is operating at mains
potential, so do not touch the components unless the power is off and the
IEC power leads have been disconnected for at least ten seconds.
Before applying power, check your
wiring carefully and ensure all mains
connections are covered in heatshrink
tubing and the wiring is cable tied. Then
install the 10A fuse inside CON5’s fuse
holder and verify that IC9 is plugged
into its socket and correctly orientated.
If you have installed the Mains Input
Detection circuitry, insert the 1A fuse
into CON8.
VR1 can initially be set to mid-travel
for a nominal 10-second sequence interval. If set fully anti-clockwise, VR1
gives a 100ms sequence delay period
Practical Electronics | March | 2025
Mains Power-Up Sequencer, part 2
while near full-clockwise (about 10°
away) gives a 22 second sequence interval.
Set switch S1 to the left (open) position to disable Current Detection.
Set S2 to the right for a startup delay
and S3 to the left so VR1 sets the on-
sequence period.
Remember the earlier advice to
unplug the unit before opening the
lid and adjusting any settings. Also
note that settings like the periods are
only stored at power-up. Making adjustments while the power is on won’t
do anything.
On power-up, check that the power
LED lights and that the OUT1 LED lights
after about ten seconds, followed by
OUT2 after another ten seconds. The
remaining LEDs should light after similar periods.
You can test the off-sequencing if
you have installed the Current Detection or Mains Input Detection circuitry. To do this, unplug the unit, open
the lid and move S1 to the right
(closed) position. Reinstall the lid
and power it back on.
If using Mains Input Detection,
plug CON8 into the mains and the
startup sequence should begin. Disconnect or switch off that supply
and the LEDs should switch off in sequence, starting with the last output
and finishing with OUT1. The default delay for the off-sequence is
two seconds.
Alternatively, if using the Current
Detection circuitry instead, plug an
appliance into OUT1 and switch it
on to trigger the on-sequence, then
unplug it or switch it off to trigger the
off-sequence. Again, the off-sequence
should start with the last output and
finish with OUT1.
These
Australian mains
sockets are smaller than the
UK versions so they are able to fit
side-by-side.
Exposed terminals should be covered with heatshrink
tubing, while the active busbar on the IEC connected
must be covered with neutral cure silicone for
safety.
Settings
Two lots of settings can be made.
First, there are the on-sequence and
off-sequence periods, set using VR1.
The on-sequence period is set with
switch S3 in the left position and is
only stored at the instant that power
is switched on. To set the off-sequence
rate, you also use VR1, but place S3 in
the right-hand position before powering it up.
Each value is stored in flash memory,
so it is recalled at power up, allowing you to set these two periods independently.
For these settings, VR1 can be adjusted from fully anti-clockwise to
Practical Electronics | March | 2025
65
Constructional Project
www.poscope.com/epe
- USB
- Ethernet
- Web server
- Modbus
- CNC (Mach3/4)
- IO
- PWM
- Encoders
- LCD
- Analog inputs
- Compact PLC
- up to 256
- up to 32
microsteps
microsteps
- 50 V / 6 A
- 30 V / 2.5 A
- USB configuration
- Isolated
PoScope Mega1+
PoScope Mega50
The finished
Mains Power-Up
Sequencer, including the Mains Input
Detection feature. This prototype uses Australian
sockets, but we have updated the drilling details and created a
label to suit the larger UK BS1363 sockets, which won’t fit side-by-side.
about 10° short of fully clockwise. That
gives a range of 100ms (anticlockwise)
to about 22s (near clockwise).
The other settings are made with VR1
set fully clockwise, which causes the
Sequencer to enter another mode. It
does two things in this position.
One is to measure the voltage from
the precision rectifier when no appliance is connected to OUT1. This is the
offset voltage from the op amp circuit,
which is usually a few millivolts. This
value is stored and subtracted from
any future Current Detection measurements. If you are not using the Current
Detection, it still happens but won’t
affect anything.
The other function of this mode
is setting the off-sequence direction.
With the power off and the unit unplugged from the wall, rotate VR1
fully clockwise. No appliance should
be plugged into the sequencer GPO
(OUT1) outlet or any mains power
applied to the Mains Detect Input
(if used).
If switch S3 is set to the right, you
will set the off-sequence to forward,
meaning that OUT1 switches off first.
If S3 is placed to the left, it sets the
reverse off-sequence direction, so the
last outlet switches off first. The initial setting of the programmed microcontroller is this reverse off-sequence.
After a few seconds in this mode,
the Sequencer can be unplugged.
After that, remove the lid and rotate
VR1 back from fully clockwise to
the desired period for the sequence
rate, depending on the position of S3.
This is important as, if VR1 is left set
at the fully clockwise position, the
Sequencer will not run to switch on
any outlets.
Table 2 summarises the functions of
switches S1, S2, S3 and potentiometer VR1. Settings are only changed at
PE
power-up.
Table 2 – power-up settings
- up to 50MS/s
- resolution up to 12bit
- Lowest power consumption
- Smallest and lightest
- 7 in 1: Oscilloscope, FFT, X/Y,
Recorder, Logic Analyzer, Protocol
decoder, Signal generator
66
Switch
Left (open)
Right (closed)
VR1
S1
No Mains/Current Mains/Current
Detection
Detection enabled
S2
No initial delay
Delay before on
and off sequences
S3
VR1 sets on-rate
VR1 sets off-rate
100ms to 22s
(from full anti-clockwise to
10° less than clockwise)
S3
Reverse
off-sequence
Forward
off-sequence
Fully clockwise
(also stores full wave
rectifier offset)
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