Campbell Scientific CR10 CR10 Measurement and Control - Page 51

SECTION

3.

INSTRUCTION

SET BASICS

The

instructions

used to

program

the

CRl0

are divided into four types: lnpuUOutput

(l/O),

Processing,

Output

Processing, and Program

Control.

l/O

Instructions

are

used

to

make measurements and

store

the readings in

input

locations or

to

initiate

analog

or digital

port

output.

Processing

lnstructions

pertorm

mathematical operations using data from

lnput

Storage locations

and

place

the

results

back

into

specified

lnput

Storage

locations.

Output

Processing

lnstructions

provide

a

method

for

generating

time

or event dependent data summaries from

processed

sensor readings residing in

specified lnput Storage

tocations.

Program

Control

lnstructions

are

used to direct

program

execution based

on

time and

or

conditionalfests

on

input

data and to direct output to external devices.

lnstructions

are identified by

a

number.

There are

a

fixed

number

of

parameters

associated with each

instruction

to

give

the

CRl0

the information required

to

execute

the

instruction.

The

set

of

instructions

available

in

the

CRl0

is determined by the PROM (Programmable Read Only Memory) inside the

CR|0.

Appendix

B

lists

the PROM options available.

3.1

PARAMETER DATA TYPES

There are 3 different data

types

used

for

lnstruction parameters:

Floating Point (FP),

4

digit integers

(4), and 2

digit

integers

(2).

The

parameter data

type

is identified

in

the

listings

of

the

instruction

parameters

in Sections 9-12.

Different data types

are

used to allow

the

CR10

to

make

the

most

efficient

use

of

its memory.

Floating Point parameters

are

used

to enter

numeric constants for

calibrations or

mathematical

operations. While

it

is

only

possible

to

enter 5

digits

(magnitude +.00001

to

+99999.),

the internalformat

has

a

much

greater range (1xlO-191e 9;1918, Section

2.2.1).

Instruction 30

can

be used

to

enter a

number in

scientific

notation into

an

input

location.

3.2

REPETITIONS

The

repetitions parameter

on

many of

the

l/O,

Processing, and

Output

Processing Instructions

is used

to

repeat

the

instruction on

a

number of

sequential

Input Channels

or

Input Storage

locations.

For

example,

if

you are

making

4

differentialvoltage

measurements on

the

same

voltage

range, wire

the

inputs to sequential

channels and enter

the

Differential Voltage

Measurement lnstruction once with

4

repetitions,

rather

than

entering 4

separate

measurement

instructions. The

instruction

will

make

4

measurements starting on

the

specified channel

number and continuing

through

the 3 succeeding

differentialchannels.

The

results

will

be stored

in

the specified input location and the

3

succeeding input

locations.

Averages for all 4

measurements

can

be

calculated

by entering

the

Average

Instruction

with 4

repetitions.

When

several

of

the

same

type

of

measurements

will be

made, but

the

calibrations

of

the

sensors are

different,

it

requires less time

to

make

the

measurements

using

one

measurement

with

repetitions and

then

apply the calibrations

with

a scaling array

(lnst.

53)

than

it

does to enter

the

instruction

several

times

in order

to

use a different

multiplier and

offset.

This is due to set up and

calibration time

for each

measurement

instruction.

However,

if

time

is not

a

constraint,

separate

instructions may make

the

program

easier to follow.

3.3

ENTERING NEGATIVE NUMBERS

After

keying in

a

number, press C

or

"-"

to

change

the

number's

sign.

On

floating

point

numbers a minus sign

(-)

will

appear to

the

left

of

the

number.

Excitation

voltages

in millivolts

for l/O

lnstructions are

4

digit

integers; when C

is keyed

2

minus

signs

(-)

will

appear to

the

right

of

the

number indicating

a

negative

excitation.

Even though this display

is

the same

as

that

indicating

an

indexed input location,

(Section 3.4)

there

is no indexing effect on

excitation voltage.

3.4

INDEXING

INPUT LOCATIONS AND

PORTS

When

used within

a

loop,

the

parameters

for

input

locations and the commands

to

set,

toggle, or

pulse

a

port can

be

Indexed to the

loop

counter.

The

loop

counter

is

added to

the

indexed value to determine

the actual

lnput

Location

or

Port

the

instruction acts on.

Normally the loop

counter

is incremented

by

1

after each pass through

the

loop.

lnstruction

3-1

Campbell Scientific CR10 CR10 Measurement and Control - Page 51

Set Basics

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