Eberline ESP-1 - Page 47

96 pages

Save Page as PDF

To Next Page

To Next Page

To Previous Page

To Previous Page

Loading...

the

first

character

on

the

display

at

each

display

update

(output),

warning

the

operator

of

the

low-battery

condition.

(5)

CNT

(count)

input

is

a

signal

the

rate

of

which

is

proportional

to

the

radiation

intensity

at

the

detector.

The

rate

is

calculated

by

the

program

(counts/time).

The

calibration

constant

(CC)

and

correction

factor

(CF

[based

on

detector

dead

time])

result

in

a

value

in

radiation

units

as

calibrated.

The

length

of

the

bar

graph

is

also

calculated.

The

results

are

then

Output

to

the

display

for the

operator.

Outputs:

(1)

"PWR

ON"

(power

on,

active

low)

is

output

under

program

control

to

turn

the

power

to

the

instrument

on

or

off

(see

"Low

Voltage

Supply,"

section

IV.C.1).

(2)

"SPKR"

(speaker

on,

active

low)

is

output

under

program

control

when

the

SPKR

keypad

is

pressed.

The

output

is

complemented

at

each

press

of

the

keypad.

This

results

in

a

push-on/push-off

action

of

the

SPKR

keypad

(see

"Speaker,"

section

IV.C.4).

(3)

"ALM"

(alarm

output,

active

low)

is

output

activated

when

the

program

has

sensed

that

the

calculated

reading

has

exceeded

the

value

input

by

the

operator

for

"ALM

AT"

(alarm

setting).

"SPKR"

output

is

also

activated

to

turn

the

speaker

on

(see

"Speaker,"

section

IV.CA).

(4)

The

display

is

a

liquid

crystal

(LCD)

5

x

7

dot

matrix

character,

2

lines

of

16

characters

per

line.

This

allows

the

full

alphanumeric

ASCII

character

set

as

well

as

the

special

characters

used

to

display

the

analog

bar

graph.

The

LCD

is

a

"smart"

display

in

that

it

is

supported

by

its

own

microprocessor

and

program,

thus

relieving

the

computer

of

this

processing

load.

The

computer

outputs

to

the

LCD

command

instructions

and

data

to

be

displayed,

based

on

the

tasks

being

performed.

These

data/commands

are

passed

to

the

display

via

the

8-bit

address-data

bus

(Al,

port

PO).

A

command

(instruction)

is

differentiated

from

data

(character-to-display)

by

address

line

14

(Al,

pin

27),

high

equals

command.

The

command/data

are

accepted

by

the

LCD

when

"WR"

(ΑΙ,

pin

16)

is

low

simultaneously

with

address

line

15

(A1,

pin

28)

being

low.

This

yields

an

address

of

8000H

for

data

and

ОСОООН

for

commands.

The

LCD

requires

its

"E"

(enable,

pin

6)

to

be

strobed

0.14

microseconds

(minimum)

after

data

and

addresses

are

stable.

The

quad

NOR

gate,

(A4)

and

R-C

time

constants

provided

by

R2-C6

and

КІ-С5

accomplish

this.

The

viewing

angle

of

the

display

may

be

changed

by

varying

the

V,

input

(pin

3).

The

display

is

not

considered

to

be

field

repairable.

Memory

and

CPU:

АП

RAM

registers

and

timers

are

contained

within

the

microcomputer

chip

and

are

not

available

to

be

observed.

Their

functions

are

solely

to

control

the

program

(i.e.,

program

counter

and

stack

pointer)

or

for

use

by

the

program

to

perform

its

tasks

(RAM

and

ALU).

ESP1.MAN/February

1992

4-5

Related product manuals