Campbell 21X Manuel de l'opérateur télécharger pdf (Page 99)

SECTION

9. INPUT/OUTPUT

INSTRUCTIONS

PARAM.

DATA

NUMBER

TYPE DESCRIPTION

Repetitions

Input

channel number

of

first measurement

Excitation

channel

number

Input

location for first

measurement

Multiplier

Offset

Input locations

altered: 1 for

each thermistor

channel

***

12

207

RELATIVE

HUMIDITY

PROBE

***

FUNCTION

This

instruction

applies a 3 VAC

excitation

across

Campbell Scientific's Model

207

Temperature

and RH Probe, makes

a fast

single-ended

measurement across

a series

resistor

on

the 150mV range,

calculates the

result with

a

fifth

order

polynomial,

and

performs

the

required temperature

compensation

before

outputting

the result

in %

RH.

When

measuring several

probes,

allthe RH

elements should

be

connected sequentially.

The

temperature

values used

to correct the RH

measurements

should also be

stored

sequentially

to make

use of the REP feature in

Instruction

11.

NOTE: The

temperature value

used

in

compensating

the

RH value

(Parameter

5)

must

be

obtained

(see

Instruction 1

1)

prior

to executing

Instruction

12.

The

RH results

are

placed

sequentially

into

the

input

locations

beginning with

the first RH value.

In the 207

probe,

the

RH

and

temperature

elements use

a common excitation

line. NEVER

EXCITE

THE2O7 PROBE WITH

DC

EXCITATION

(this

includes ohm

meters) as

the

RH

chip will be damaged.

The

maximum

error from the

polynomial

used

for

calculating RH

is

given

here:

Range

(%RH)

10

-

100

15-94

Error

(%RH)

PARAM.

DATA

NUMBER TYPE DESCRIPTION

Repetitions

First

channelfor

RH

measurement

Excitation

channel

number

Input

location for first

compensating

temperature

measurement

Input

location for first

RH

measurement

Multiplier

Offset

Input locations

altered:

1 for

each

RH

measurement

***

13

THERMOCOUPLE

TEMPERATURE.

SINGLE-ENDED

FUNCTION

This

instruction uses the selected

calibration to calculate the thermocouple

output

voltage at the reference

temperature, then it

makes a SINGLE-ENDED VOLTAGE

MEASUREMENT

(Section

13.2)

on the

thermocouple

and adds the measured

voltage

to the calculated reference voltage,

then

converts the voltage to temperature in

oC.

Select the

smallest voltage range that will

accommodate the

temperatures bein

g

measured

(Table

9-4).

PARAM. DATA

NUMBER

TYPE DESCRIPTION

Repetitions

Range

code

First TC

channel

Thermocouple type

code

Reference

temperature

location

Destination input

location

Multiplier

Offset

Input locations

altered: 1 for

each

thermocouple

channel

t4

t1

01:

02:

03:

05:

06:

2

2

2

4

FP

FP

2

2

2

4

01:

o2:

03:

o4:

05:

06:

07;

FP

FP

2

2

2

2

4

4

FP

FP

01:

02:

03:

Q4:

05:

06:

07:

08:

9-6

1 2 ... 94 95 96 97 98 99 100 101 102 103 104 ... 190 191

Commentaires sur ces manuels

Pas de commentaire