Campbell Scientific CR10 CR10 Measurement and Control - Page 207

PRINT

PERIPHERAL:

See

Print Device.

PROCESSING

INSTRUCTIONS: These

Instructions allow

the

user to

further

process

input data values

and

return

the

result

to

lnput

Storage

where

it

can

be accessed for output

processing.

Arithmetic

and transcendental

functions are

included

in

these

Instructions.

PROGRAM CONTROL

INSTRUCTIONS:

Used

to

modify

the

sequence of execution of

Instructions

contained

in Program Tables; also

used to set or clear flags.

PROGRAM

TABLE:

That

portion

of

memory

allocated for

storing

programs

consisting

of

a

sequence

of

user instructions

which

control

data acquisition, processing, and output

to

Final

Storage.

Programming

can

be

separated

into

2

tables,

each

having its

own

user-entered

Execution

lnterual.

A third

table

is available

for

programming subroutines

which

may

be

called

by instructions

in

Tables

1

or

2.

The

*1

and

*2

Modes

are

used to access

Tables

1

and

2.

The

*3

Mode is used to access Subroutine

Table

3.

The

length of the

tables

is

constrained only by

the

total

memory available

for

programming

(Section

1.5).

Tables

1

and

2

have independent

execution intervals. Table

1

execution

has

the

higher priority; it may interrupt Table

2.

RING

LINE

(PlN

3):

Line pulled high by

an

externaldevice to

"awaken" the CR10.

SAMPLE

RATE:

The

rate at which

measurements

are

made.

The

measurement

sample

rate is primarily

of

interest when

considering the

effect

of

time

skew

(i.e., how

close

in

time

are a

series of

measurements).

The

maximum

sample

rates are

the

rates at

which

measurements

are

made

when

initiated

by

a

single

instruction

with

multiple repetitions.

APPENDIX

A.

GLOSSARY

SIGNATURE:

A

number

which

is

a

function

of

the

data

and

the

sequence of

data

in memory.

It

is

derived

using an algorithm which assures a

99.998% probability

that

if

either

the

data

or

its

sequence changes,

the

signature changes.

SYNCHRONOUS: The transmission ol

data

between

a

transmitting

and receiving device

occurs as a series of zeros and

ones.

For

the

data

to

be "read" correctly,

the

receiving device

must

begin

reading at the proper

point

in

the

series.

In

synchronous communication, this

coordination

is

accomplished by synchronizing

the

transmitting and

receiving devices

to

a

common clock

signal

(see Asynchronous).

THROUGHPUT:

The

throughput

rate

is

the

rate at which

a

measurement

can be

made,

scaled

to engineering

units, and

the

reading

stored in

Final

Storage.

The

CR10 has

the

ability

to

scan sensors at

a

rate exceeding

the

throughput

rate (see

SAMPLE RATE). The

primary

factor

affecting

throughput

rate

is

the

amount

of

processing specified by

the

user.

In

normal operation, all processing called

for

by

an

instruction

must be

completed

before moving on

the

next

instruction. The

maximum

throughput

rate

for

a

fast

single-ended

measurement

is

approximately

192 measurements per second

(12

measurements, repeated

16

times

per

second).

This

rate is possible

if

the

CR10's

self-calibration

function

is

suspended

(this

is

accomplished by

entering

Instruction

24

into

Program

Table

2

while

leaving

the

Execution

f

nterual

0

so

Program Table

2

never

executes).

When

the

self-calibration

function

is operating,

the

maximum

throughput

rate

for

a

fast,

single-

ended

measurement

is

192 measurements per

second

(12

measurements,

16

times

per

second).

A-3

Campbell Scientific CR10 CR10 Measurement and Control - Page 207

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