3-3

3.3.1.With timer control

Operation,

using

a

timer,

 

is

as

follows:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 .

 

Check

that

generator

kV

and

mA

settings

 

are

 

correct.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.

 

Determine

the

exposure time, and set the

timer

for

 

the required window shutter. The clear

plastic

cover

is

 

 

rotated until the black pointer is set to the

 

required

time

(0

to 6),

while the centre knob is

rotated

in

a

 

 

 

clockwise direction until the required multiplication factor (x1, x10 : seconds, minutes or hours) is against

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

the

arrow.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

When timing

commences the red pointer will gradually return to zero, then the timer microswitches return

 

 

to the normal position (off), the timer and

the

 

red

pointer

returns

to

the

position

set

by

the

black

 

 

 

 

 

pointer.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.

 

Set the three

-

position

SHUTTERS

switch

to

select

the

required

window

shutter,

e.g.

when

window

3

is

to

 

 

be

used the

right-hand

switch

is

set

to

3;

and

 

the

time

must

be

set

by the

right-hand

timer.

 

 

 

 

 

 

4.

 

Open the shutter by operating the lowest SHUTTERS push-button simultaneously with the required

 

 

 

 

SHUTTERS

I

push-button. Whent he shutter

 

is

open

the X-ray beam

passes

to

the

sample

 

in

the camera,

 

 

the

red

lamp

on

the

tube

shield

(below

the

filter/shutter disc)

is

lit, the

red

flags

 

will

appear

in the

holes

 

 

 

on

either

side

of

the

tube

shield,

 

and the

timer

operation

 

will

 

commence.

 

 

 

 

 

 

 

 

 

 

 

 

5. When the preset

time

 

has

elapsed

the

shutter is

closed,

and

 

the

whole

instrument

is

switched

off

unless

a

 

 

 

shutter

is

open

at another tube

shield

position.

 

X-rays

will be

generated

as

long

as one or

 

more

shutters

 

 

 

are

open.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTE:

The

red

warning

 

lamps

are

fail

safe,

and

the

shutters

will

close

if

a

bulb

filament

is

broken

when

a

 

 

 

 

shutter

is

open.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.3.2.Without timers

When a timer is not used, or is

not fitted, proceed as follows:

 

 

 

 

 

 

 

 

1

.

Check that the generator kV

and mA settings are correct.

 

 

 

 

 

 

 

 

2

.

Ensure that the 3 - position

switches

are

in

the

mid-position.

 

 

 

 

 

 

 

3

.

Open the shutter by operating the lowest SHUTTERS push-button simultaneously with the required

 

 

SHUTTERS I push-button. The

shutter

will

open and

the X-ray

beam

passes

to

the sample

in

the

camera,

 

 

the red lamp on the tube shield is

lit,

and

the

red

flags will

appear in

the holes on either side

of the

tube shield.

4

.

When the exposure time has elapsed, operate the SHUTTER 0 push-button. The shutter will

close,

 

 

 

and the generator will switch

off

unless a

shutter

is

open

at

another

tube

shield

position. X-rays

will be

 

 

generated as long as one or

more

shutters

are

open.

 

 

 

 

 

 

 

 

 

3.4.SWITCHING OFF A MOTOR WHEN THE SHUTTER CLOSES

Cameras

can

be

fitted with

motors, either

for

moving

film, or a

crystal,

or

for

spinning

the

sample.

 

If

required.

the motor operation can be switched off when the timer reaches its zero position, and it will remain off

 

until

the

timer is reset (if one or more

shutters

are still open). The two outside a.c. mains sockets on the rear

panel

are

used

for

this

purpose,

and

it

is

 

necessary for a jumper wire to be removed between terminals

25 and

26 on the rear of

the timer, refer to the

Service Part.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The mains connector for the motor used in

the

tube

shield

position

1

 

or

2,

 

must

be

plugged

into

the

mains

socket immediately behind, i.e. adjacent to

the left-hand side panel. A

motor

used

for

positions

3

or

 

4

will

be

connected

to

the

left-hand socket on the

 

rear

 

panel (viewed from the rear).

 

 

 

 

 

 

 

 

 

 

 

 

The

procedure

for

analysis

is

as

described

 

in

 

paragraph

3.3.1.,

but

now

the

 

camera

motor

will

start

at the

moment

that the Starting relay operates, when GENERATOR I is depressed.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

When

the

shutter is opened the timer

will

start,

 

and at the end of

the

preset

time

when

the

shutter

closes,

 

the motor

will also stop. If another

shutter

is

 

still open

the

equipment

will

not

switch

 

off,

the

timer

is

not

reset

and there is no power to the motor.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

To reset the timer and start the camera motor,

place the three-position switch

 

in

its

central

position.

If

all

 

shutters are closed

after

the

preset

time,

the

equipment

switches

off

and

the

 

timer resets.