Campbell 21X Instrukcja Operatora Pobierz pdf (Strona 170)

User

Enters

K

CR

APPENDIX

C. BINARY TELECOMMUNICATIONS

previously

executed;

four

time

bytes, a user

flags

byte, four

bytes

for

each input location

requested

in the J command, Final

Storage

data in Campbell

Scientific's binary

format if

requested

by

the

J command,

and

terminating

in 7F 00 HEX

and two signature

bytes.

The

optional

ports

byte

expresses

the

datalogger

port

status. The most significant

bit

represents

Port 8, and

so on to

the least

significant bit which represents Port1.

For each input

location requested by the J

command four

bytes of data are

returned. The

bytes

are coded in Campbell

Scientific,

Inc.

Floating Point Format.

The format

is

decoded

to the following:

Si

g

n

(Mantissa*2(ExPonent))

The Data byte 1

contains the Sign

and

the

Exponent.

The most significant bit represents

the Sign; if reset

the Sign

is

positive.

Subtract

40,hex from

the 7 least significant bits to obtain

the

signed exponent.

Data

bytes 2lo 4 are

a binary

representation of

the mantissa with

byte 2 the most

significant

and 4 the least. The

mantissa ranges

in value

from

80 00 00 HEX

(.5

decimal) to FF

FF FF HEX

(1

bit less

than

1

decimal, 1-2-2\.

As

an example, 41

80 OO OO

HEX

=

+(.5.2(+1);

=.5*2=ldecimal.

Note Exceptions:

00

HEX=

Odecimal

FF

HEX

=

-99999

decima

lf appropriately requested

by a J command,

Final

Storage data, if

any,

will immediately

follow

the input location

data. Refer

to the

datalogger manual for

a description

of how to

decode FinalStorage

data in

Campbell

Scientitic's binary

data

format.

Final

Storage

data will

be

limited

to not more

than

1024

bvtes

per

K

command.

The K

command data is

terminated

with

7F 00

HEX

(a

unique binary format

code)

followed by

two signature bytes. Refer

to the datalogger

manual for

the

meaning

and calculation of the

signature

bytes. The signature

in this

case is a

function

of the first time

byte through

the 7F OO

HEX bytes.

Calculate the signature

of

the bytes

received

and compare with

the signature

received

to determine the validity

of

the

transmission.

Datalogger

Echo

K

CR

LF

Time Minutes byte 1

Time Minutes byte 2

Time Tenths

byte 1

Time Tenths

byte 2

Flags byte

Ports byte

(if

requested)

Datal byte

1

Datal byte 2

Datal byte 3

Datal

byte

4

Data2

byte

1

Data2

byte

2

Data2 byte 3

Data2

byte

4

DataN byte 1

DataN

byte

2

DataN byte 3

DataN

byte

4

Final

Storage

Data

bytes

01111111 binary byte

00000000 binary

byte

Signature byte

1

Signature byte 2

00 00 00

FF

FF FF

Time

Minutes byte

1 is most significant.

Convert from

binary to decimal. Divide

by 60 to

get

hours,

the remainder

is

minutes.

For

example,

00000001

01011001

(01

59 HEX)

is

345

decimal minutes

or 5:45.

Time Tenths

byte 1

is most

significant.

Convert

from

binary to decimal.

Divide by 10

to

get

seconds

and tenths

of seconds.

For

example,

00000001 11000110

(01

CO HEX) is

454

decimal

or 45.4

seconds.

Thus

the datalogger

time for

01

59 01 CG HEX

is

5:45:45.4.

The

Flags

byte

expresses datalogger

user flag

status. The most

significant bit represents

Flag

8, and

so on to

the least

significant bit which

represents

Flag 1.

lf a

bit

is

set, the

user flag is

set in

the datalogger.

c-2

1 2 ... 165 166 167 168 169 170 171 172 173 174 175 ... 190 191

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