SC_12V_24V_Speed_controller_pt2.pdf

(4526 KB) Pobierz

Last month, we described the circuit and

software features of our new High-Current

DC Motor Speed Controller. This month, we

show you how to build and test

it.

HE DC MOTOR Speed Controller

is built on two PC boards: a main

board coded 09103081 (124 x 118mm)

and a display board coded 09103082

(73 x 58mm). These are joined together

via a 12-way flat ribbon cable which

plugs into a pin header on the main

board.

The main board can be assembled

first - see Fig.9. Start by checking the

PC board for hairline cracks and for

any visible shorts, especially between

the ground plane and any adjacent

tracks. In addition, check the hole sizes

for the larger hardware items by test

fitting these parts into position.

SILICON CHIP

That done, begin by installing the

17 wire links. These must go in first,

since some of them run under com

ponents.

To straighten the link wire, first

clamp one end in a vice, then stretch

it slightly by pulling on the other end

with a pair of pliers. It's then just a

matter of cutting the links to length and

bending their leads down through 90°

to match the holes in the PC board.

The' resistors are next on the list.

Table 1 shows the resistor colour codes

but you should also check each one

using a digital multimeter before in

stalling

on the board, as some colours

can be difficult to decipher.

Note that resistor Rl should be lkQ

if the supply voltage will be higher

than or equal to 16V. Alternatively, use

a 100Q resistor if the supply voltage is

going to be less than 16V. The 22Q 1W

resistor (on the lefthand side of Fig.9)

should be mounted 3-4mm proud of

the PC board to aid heat dissipation.

Once the resistors are in, install

the diodes and the zener diodes. Take

care to ensure that these are all cor

rectly oriented and note that diode D2

(near inductor Ll) must be a IN5819

Schottky type.

Take care also with the zener diodes.

ZDI-ZD5 are all16V 1W types, while

ZD6 and ZD7 are 33V 5W types. The

fast recovery diode (D3) can be left

until later as there are two options

for this.

The next thing to do is to solder in

the four power Mosfets (Q5-Q8). These

come in a TO-220 package and sit

siliconchip.com.au

HEAVY DUTY

lERMINAL BLOCKS

AOEPF06

Kf"JnD3.

.©~-

.@~D.

TOBAmRY+

TO MOTOR +

•

~ .©~.-"

·©~DI--·;

•

TO MOTOR

TOMOTOR

·@~DI-_o

TOBAmRY

·©~D·-

VRl

(AlJERNATlVE

POSITION)

TOBAmRY

'U<16

NOTE: USE NEUTRAL-CURE

SILICONE SEALANT TO SECURE

INOUCTOR L1 ANO THE 2200l-lF

LOW·ESR CAPACITOR

Fig.9: install the parts on the main PC board as shown on this layout diagram, starting with the t7 wire

links. The 40EPF06PBF 40A fast recovery diode (D3) is shown in position here but you can also use two

MBR20tOOCT 20A diodes connected in parallel (see Fig.tO). Note the alternative positions for VRt.

horizontally on the PC board. Note that

the source lead of each device extends

further than the other two.

Before mounting each device, you

will have to first position it on the PC

board and bend its leads down through

90°

so that they mate with the holes

in the board. That done, fasten each

device to the PC board using an M3 x

6mm screw and nut before soldering

its leads.

Do not solder the leads before bolt

ing the metal tab down.

you do, you

risk stressing the soldered joints as the

screw is tightened and this could crack

the copper or lift the pads.

The next thing to do is to solder in

the two IC sockets. Make sure these are

oriented correctly as per the compo

nent overlay.

is important that you

use IC sockets because calibration of

the +5V rail is done with microcontrol

leI' ICI out of circuit. This is described

later during the setting-up stage.

siliconchip.com.au

Now the four bipolar transistors can

be soldered in. There are three BC337

NPN types

(Q2-Q4)

and one BC327

PNP type (Qt) - don't get them mixed

up. Their leads will only go in one way

and it's just a matter of pushing them

down onto the board as far as they

will comfortably go before soldering

the leads.

The single 3mm red LED can go

in next, again taking care to orient it

correctly. Its anode lead is the longer

of the two.

Follow this with trimpot VR2 and

the piezo buzzer. Note that the buzzer

must be installed with its positive

terminal towards the bottom edge of

the board - see Fig.9.

Once these parts are in, you can

solder the capacitors in place. The ce

ramic, monolithic and MKT types can

go in either way around but be sure to

orient the electrolytics correctly. The

large low-ESR 2200IJ.F capacitor sits

horizontally on the PC board with its

leads bent at

90°

to go through their

holes in the board.

The SPDT horizontal toggle switch

(SI) can be soldered in next. Alterna

tively, this part can be mounted on a

panel and connected back to the PC

board via flying leads - it all depends

on how you intend mounting the

board.

The 220IJ.H toroid inductor (Ll) sits

vertically on the PC board - see photo.

Be sure to strip the enamel from its

leads and tin them with solder before

attempting to solder it in position.

CONI, the 12-way header, is next

on the list. This should be oriented as

shown on Fig.9 and the photographs.

That done, mount the two heavy-duty

3-way screw terminal blocks. Note that

these are dovetailed together to make

a 6-way block before mounting them

on the board.

Potentiometer VRl can now be

APRIL 2008

Value

J.1F Code IEC Code EIA Code

220n

10011

470p

224

104

471

220nF O.n/lF

100nF 0.1/lF

470pF

This view shows the fully assembled main board. Note that this prototype

board differs slightly from the final version shown in Fig.9.

installed. There are two possible loca

tions on the board for this part. Mount

it in the position that's the most con

venient for your application (but don't

install a pot in both positions).

Alternatively, the pot can be mount

ed off the board and connected to its

mounting pads via flying leads.

Leave the two ICs out oftheir sockets

for now. We'll cover their installation

later in the article.

Fast recovery diode

Now for the fast recovery diode

(D3).

you are using the 40EPF06PBF

diode (rated at 40A), then this can be

soldered straight in as shovvn in Fig.g

and the photo at left. Make sure that

it goes in with its metal face towards

the screw terminal block.

Alternatively, if you are using the

two MBR20100CT 20A diodes, then

these must be connected in parallel

and installed as shown in Fig.10 and

its accompanying photos. These par

ticular diodes come in TO-220 pack

ages and each package itself contains

two lOA diodes which are used in

parallel.

The middle lead connects to the tab

and is the cathode. This middle lead

must be cut off using a small

pair ofsidecutters. as the tabs

are used to make the cathode

connections to the board. The

two outer leads of each device

are the anode connections.

The procedure for mounting

these two diodes is as follows:

(1) Drill the hole for the cathode con

nection on the PC board to 3mm.

(2) Lightly tin the copper around the

two mounting holes (this is necessary

to ensure good contact with the screw

heads).

(3) Secure the metal tab of the first

device to the PC board using an M3 x

12mm screw and nut, with the screw

passing up from the underside of the

board. Tighten the nut down firmly.

(3) Install an M3 x 12mm screw

through the hole at the anode end of

the diodes, secure it with a nut, then

No.

Value

33kQ

4.7kQ

3.6kQ

1kQ

470Q

100Q

56Q

39Q

22Q

15Q

4-Band Code (1 %)

orange orange orange brown

yellow violet red brown

orange blue red brown

brown black red brown

yellow violet brown brown

brown black brown brown

green blue black brown

orange white black brown

red red black brown

brown green black brown

brown black gold gold

5-Band Code (1%)

orange orange black red brown

yellow violet black brown brown

orange blue black brown brown

brown black black brown brown

yellow violet black black brown

brown black black black brown

green blue black gold brown

orange white black gold brown

red red black gold brown

brown green black gold brown

brown black black silver brown

SlLlCON CHlP

siliconchip. com. au

F=~;e;;#~

~~~

M3NUTS

•

DIODE LEADS

SOLDERED TO LUGS

I,..CUT HERE

~~~~~~;~S~O~LDER

LUGSBOARD

-PC

' - PC BOARD COPPER

TRUNCATED

Fig.IO: this

diagram

the

two photos

below show

how to install

the alternative

MBR20100CT

FRONT PANELS

--..r'~~NCLOSURES

fast recovery

diodes (D3).

• Cost-effective prototypes

and production runs

• Wide range of mat

ial

customization of

. material

• Automatic price calculation

• Fabrication in

3 or

days

In this photo, the first diode has been

fastened into position and its two

outer leads soldered to the solder lug.

fit a solder lug and secure

with a

second nut. Again, make sure the nuts

are done up tightly.

(4) Solder the two outer leads of this

first device to the solder lug, then fit

another solder lug and nut.

(5) Secure the tab of the second device

in position and solder its outer leads

to the top solder lug.

The second diode is then mounted in

position and its outer leads soldered

to the top solder lug.

Alternatively, IC3 can be directly

soldered to the PC board. Be sure to

install the IC with the correct orienta

tion - ie, its notched end goes towards

CON2.

Finally, complete the display board

assembly by installing a I2-way pin

header (this part is optional), the two

pushbutton switches and the four 7

segment displays. Be sure to orient

the displays with the decimal points

at bottom right.

Similarly, make sure that the push

button switches are correctly orient

ed. As shown in Fig.ll, they must each

be installed with the flat side towards

the displays.

Sample price:

•.

USD43.78 plus S&H ...

. r=-"

rrrr

r:' :

www.frontpanelexpress.com

Building the display board

The display board is optional but

will be useful in many applications.

you decide not to build it, you will

not be able to change the settings and

default values will have to be used.

You will also have no way of know

ing what percentage of full speed the

motor is running at.

As before, check the board for de

fects. In particular, check for shorts

between tracks or between the ground

plane and any adjacent tracks.

That done, start the assembly by

installing the 23 wire links. Some of

these sit under the 7-segment LED

displays, so make sure these links sit

flat against the PC board. Don't forget

the short links immediately to the left

of CONI and at bottom right.

The resistors can go in next, fol

lowed by the 100nF capacitor and

the four transistors (Q9-QI2).

you

are using an IC socket for IC3, then

this can also now go in. Install it with

its notched end positioned as indi

cated on the diagram, then install IC3

(74HC595).

siliconchip.com.au

ANTRIM

TRANSFORMERS

manufactured in

Australia

Connecting the boards

Once the board assemblies are com

plete' make up a I2-way ribbon cable

to connect the two boards together.

This should be terminated at either

end to a I2-way header plug. Be sure

to arrange this cable so that pin 1 of

the header of the main board connects

to pin 1 of the header of the display

board and so on.

Harbuch

Electronics

Pty Ltd

Toroidal - Conventional TX - Power

- Audio - Valve - Specials

- Medical - Isolated

Stepdown

- Encased Power Supplies

Set-up

Once you have completed the con

struction, the next step is to go through

the setting up procedure. You also

need to adjust trimpot VR2 on the

main board, so that the output from

the MC30463 IC (IC2) sits at exactly

+5V (this rail needs to be at exactly

+5V to ensure that the voltage meas

APRIL 2008

Question;

is the display board op

tional?

Answer:

yes the display board is op

tional and the DC Motor Speed Control

ler will function without it. However, the

display board is necessary if you want to

change the settings of the battery alarm,

the audible cues and the frequency of

the PWM, as well as to view the current

speed of the motor and the values of

the settings.

We therefore recommend that you

build the display board as well, even if

you use it to change the settings only

once. If this board is subsequently

disconnected, the speed controller will

still work and will use the last settings

stored in the microcontroller's non-vola

tile memory.

Problem:

when using the display board,

not all digits light up. What should I

do?

Answer:

check the 12-way cable and

the pin header connections. Check that

all 12 connections are good.

Problem:

the voltage at the cathode of

lD1

is nowhere near 12-16V (it should

be 16V if the supply voltage is 16V or

greater).

Answer:

check the orientation of l01

and check for incorrect power supply

connections.

Problem:

the power supply voltage

does not appear on the cathode of 01.

Answer:

in normal operation, 01 's

cathode should sit about 0.6V below the

supply voltage. This cathode should not

exceed 40V at any time, or damage may

occur to the switchmode IC and to the

microcontroller. l07, a 33V 5W zener

diode, is there to protect against high

voltages on this rail.

Problem:

some components are getting

quite hot.

Answer:

in normal operation, all com

ponents should run cool except for the

fast recovery diode (03), the four power

Mosfets 05-08 (especially if high cur

rents are being switched) and possibly

zener diodes l06

lD7,

although the

latter should not get too hot. If they do, it

could mean that the supply lead induct

ance is causing high transient voltages

on the supply rail.

Normally the low-ESR 220011F ca

pacitor should filter these out but if you

do strike problems, try minimising the

length of the power supply connecting

leads (as well as those to the motor, if

possible). You should also twist the posi

tive and negative power supply leads

together in order to cancel any magnetic

fields induced by high currents.

Problem;

the speed controller does not

respond to the pushbutton switches on

the display board.

Answer:

this could be caused by the

pushbuttons being incorrectly oriented

on the display board. Make sure the two

pushbuttons are installed with their flat

sides as indicated on the parts layout

diagram (Fig.1 0).

Problem:

LE01 (red) lights but there is

no beep from the piezo buzzer. Alter

natively, there is a beep from the piezo

buzzer but the LED does not light.

Answer:

either the LED is incorrectly

oriented or the buzzer is.

A 12-way pin header (Altronics P-5502)

should be added to the parts list (pub

lished in Pt.1) for the Display Board. You

also need two header plugs (Altronics P

5482) to terminate the 12-way cable.

if you are using a 12-16V power sup

. ply.

(6)

these voltages are OK, switch off

and install the MC34063 switchmode

IC (IC2) into its socket. Make sure that

the notch on the IC matches the notch

on the socket - ie, the notch must face

towards inductor L1.

(7) Apply power and check the voltage

at pin 1 of the 12-way header on the

main board. This is the +5V rail but

it may not yet be at exactly +5V (the

exact voltage depends on the setting

of trimpot VR2).

(8) Adjust VR2 until the voltage on pin

1 of the header is exactly +5V.

(9) Assuming that the above voltage is

now correctly set, switch off and insert

microcontroller ICl into its socket.

Make sure that its notched end goes

towards link LK11.

(10) Plug the display board into the

12-way header and apply power.

everything is working correctly (and

assuming a motor isn't connected), the

4-digit display should immediately

read "POO.O", indicating the current

speed.

(11)

it all works correctly, skip the

following troubleshooting section and

go straight to the software initialisation

.procedure.

Troubleshooting

you strike problems, the first thing

to do is go back and check the board for

any missed or bad solder joints. Check

also that there are no shorts between

tracks or between the ground plane

and any adjacent tracks.

these checks don't reveal the prob

lem, we suggest that you go through

the following checklist:

(1) Check that all 17 links are installed

on the PC board. A missing link could

mean that parts of the ground plane are

floating and this will lead to improper

operation!

(2) Check that all polarised compo

nents, including the diodes, zener

diodes, electrolytic capacitors and

ICs are correctly oriented as per the

component overlay.

(3) Check that you have used the cor

urements made by the microcontroller

are accurate).

The setting-up procedure is as fol

lows:

(1)

Check that the two ICs on the main

board are out of their sockets and that

toggle switch 51 is in the OFF position

(ie, the switch should be in the oppo

site position to that shown Fig.9).

(2) Connect a 12V-24V DC supply to

the screw terminal b}ocks (check the

supply voltage before you do this).

Note that if you are connecting the

supply leads directly to a battery, there

could be a spark when you first con

nect power due to the low-E5R 2200uF

bypass capacitor across the supply. For'

this reason, connect the supply leads

SILICON CHIP

to the battery first, then to the termi

nal blocks; as it's never a good idea to

generate a spark near a battery.

As noted previously, resistor Rl

should be lkn if you are using a supply

greater than or equal to 16V. Alterna

tively, Rl should be lOon if you are

using a supply of less than 16V.

(3) Apply power to the circuit by tog

gling 51 to ON.

(4) Check the voltage on 01's cathode.

should be about 0.6V less that the

supply voltage.

(5) Check the voltage on ZOl's cathode.

This should be very close to +16V if

you are using a power supply that's

greater than 16V. Alternatively, it

should sit between +12V and +16V

siliconchip. com.au

Plik z chomika:

gasma

SC_12V_24V_Speed_controller_pt2.pdf

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: