Campbell Scientific CR10 CR10 Measurement and Control - Page 18

CRlO

OVERVIEW

OV1.1.1 ANALOG

INPUTS

The

terminals

labeled

1H

to

6L are analog

inputs.

These

numbers refer to

the

high and

low inputs to the

differentialchannels

1

through

6.

In

a

differential

measurement, the voltage on

the

H input is measured

with

respect to

the

voltqge

on

the

L

input.

When

making,single-

ended measurements, either

the

H or L input

may be used as

an

independent channel

to

measure voltage

with

respect to

the

CR10

analog ground

(AG).

The

single-ended

channels are numbered sequentially starting

with

1H; e.9.,

the

H

and

L

sides of ditferential

channef

1

are single-ended

channels 1

and 2;

the

H

and

L

sides of

ditferentialchannel2

are

single-ended channels

3

and 4,

etc.

(The

single-ended

channel

numbers

do

NOT

appear

on older wiring panels).

OVl.1.2

SWITCHED EXCITATION

OUTPUTS

The

terminals labeled

e1,

E2,

and E3 are

precision, switched excitation outputs used to

supply programmable excitation voltages

for

resistive bridge

measurements.

DC

or

AC

excitation

at

voltages

between -2500 mV and

+2500 mV

are

user programmable (Section

9).

OVl.1.3

PULSE

INPUTS

The terminals

labeled

P1

and P2

are

the

pulse

counter inputs for

the

CR10.

They are

programmable for switch

closure,

high

frequency pulse

or

low

levelAC

(Section

9,

Instruction

3).

OV1.1.4

DIGITAL

UO

PORTS

Terminals

Cl

through

CB

are digital

lnput/Output

ports.

On power-up they are

configured

as

input ports,

commonly

used

for

reading the status of an external

signal.

High

and

low

conditions

are:

3V

<

high < 5.5V; -0.5V

<

low

<

0.8V.

Configured as outputs

the

ports allow on/otf

control of external

devices.

A

port

can

be set

high

(5V

t

0.1V), set low (<0.1V), toggled

or

pulsed (Sections

3,8.3,

and

12).

ovl.1.s

ANALOG

GROUND

(AG)

The AG

terminals

are

analog

grounds, used as

the

reference

for single-ended

measurements

and excitation return.

ovl.l.6

12V

AND

POWER GROUND (G)

TERMINALS

The

12V and power ground

(G)

terminals

are

used to supply 12V DC power to the datalogger

The

extra

12V and

G

terminals

can

be used

to

connect other devices requiring 12V power.

The

G

terminals

are also used to tie cable

shields

to

ground, and to provide a ground

reference

for

pulse counters and binary inputs.

For protection against transient voltage spikes,

power ground should

be

connected

to

a good

earth ground (Section 14.3.1).

ov1.1.7

5V OUTPUTS

The two 5Y

(tO.2o/")

outputs are

commonly

used to power peripherals such as the

QDI

Incremental Encoder Interface, AVW1 or AVW4

Vibrating

Wire

Interface.

The 5V outputs are common with

pin

1

on

the

9

pin

serialconnector;

200

mA

is

the

maximum

combined output.

ovl.1.8

SERIAL

UO

The

9 pin serial

l/O

port contains lines for serial

communication between

the

CR10 and external

devices such as

computers,

printers, Storage

Modules,

etc.

This port does

NOT

have

the

same

configuration

as

the

9

pin serial ports

currently

used

on

many

personal

It has

a

SVDC power line which is used to

peripherals such

as

the

SM192 or SM716

Storage Module

or

the

DC1

12 Phone Modem.

The

same

SVDC

supply is used for the 5V

outputs on

the

lower

terminal

strip.

Section

6

contains technical details on serial

communication.

ovl.1.9

SWTTCHED

12

VOLT

Wiring panels introduced in March 1994 include

a

switched

12

volt

output.

This

can

be used to

power sensors or

devices

requiring an

unregulated

12

volts.

The output is limited to

600 mA current.

Acontrol

port

is used to operate

the

switch.

Connect

a

wire from the

control

port to

the

switched

12

volt control

port.

When

the

port

is

set high,

the

12

volts

is

turned on; when

the

port

is low, the

switched

12

volts is

otf.

ov-4

Campbell Scientific CR10 CR10 Measurement and Control - Page 18

ovl.l.6

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