Davis Instruments Energy EnviroMonitor, Energy EnviroMonitor 7460, Energy EnviroMonitor 7465 User Manual

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ANUAL

Product # 7460 & 7465

Product Numbers: 7460/7465

Davis Instruments Part Number: 7395-071
Energy EnviroMonitor™ Console, Standard & Industrial
Rev. B Manual (7/8/99)
This product complies with the essential protection requirements of the
EC EMC Directive 89/336/EC.

© Davis Instruments Corp. 1997. All rights reserved.

EnviroMonitor™ is a trademark of Davis Instruments Corp.
WeatherLink

¨

is a registered trademark of Davis Instruments Corp.

Windows™ is a trademark of Microsoft Corp.

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Page i Energy EnviroMonitor Manual

T

ABLE OF

C

ONTENTS

I

NTRODUCTION TO THE ENERGY ENVIROMONITOR

. . . . . 1

O

PTIONAL

S

ENSORS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

O

PTIONAL

A

CCESSORIES

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

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NERGY

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NVIRO

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ONITOR

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VERVIEW

. . . . . . . . . . . . . . 5

T

HE

K

EYBOARD

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

W

EATHER

C

ONDITIONS

M

EASURED

/C

ALCULATED

. . . . . . . . . . . . . 6

Cooling Degree-Days . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Heating Degree-Days . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Temperature and Apparent Temperature . . . . . . . . . . . . . . . . . . . . . . . . 7

Wind . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Solar Radiation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Rainfall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Barometric Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Dew-Point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

P

ERIOD

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

A

UTO

C

LEAR

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

H

IGHS

AND

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OWS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

A

LARMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

U

SING

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U

SING

THE

E

NTER

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EY

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Entering Negative Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Example of Using ENTER: Setting the Time . . . . . . . . . . . . . . . . . . . . . . 16

C

OOLING

D

EGREE-

D

AYS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Viewing Cooling Degree-Days. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Selecting Units of Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Setting Cooling Degree-Days Threshold. . . . . . . . . . . . . . . . . . . . . . . . . 21

Clearing Daily Cooling Degree-Days Sum. . . . . . . . . . . . . . . . . . . . . . . . 21

H

EATING

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EGREE-

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AYS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Viewing Heating Degree-Days. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Selecting Units of Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Setting Heating Degree-Days Threshold. . . . . . . . . . . . . . . . . . . . . . . . . 25

Clearing Daily Heating Degree-Days Sum. . . . . . . . . . . . . . . . . . . . . . . . 25

Table of Contents Page ii

T

EMPERATURE

AND

A

PPARENT

T

EMPERATURE

. . . . . . . . . . . . . . . 26

Viewing Temperature and Apparent Temperature . . . . . . . . . . . . . . . . .26

Selecting Units of Measure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Highs and Lows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

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IND

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

The Compass Rose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Viewing Wind Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Selecting Units of Measure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Displaying High Wind Speed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Clearing Daily Wind Run . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

S

OLAR

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ADIATION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Viewing Solar Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Clearing Daily Solar Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

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AINFALL

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Viewing Rainfall. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Selecting Units of Measure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Entering Total Rainfall. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Displaying High Rate of Rainfall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Clearing Daily and Total Rainfall. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

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AROMETRIC

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RESSURE

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Barometric Trend Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Viewing Barometric Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Selecting Units of Measure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Entering Barometric Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

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ELATIVE

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UMIDITY

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Viewing Humidity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Displaying Highs and Lows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

D

EW

-P

OINT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Viewing Dew-Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Selecting Units of Measure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Page iii Energy EnviroMonitor Manual

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IME

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Displaying Time Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Selecting Display Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Entering Time, Date, or Year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Setting the Time for AutoClear. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Clearing Period Information/Starting a New Period . . . . . . . . . . . . . . . . 43

H

IGHS

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L

OWS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Displaying Highs and Lows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Clearing Highs and Lows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

A

LARMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

The Alarm Display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Viewing an Alarm Threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Setting a Normal Alarm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Example of Setting an Alarm—Low Outside Temperature Alarm . . . . . 47

Setting the Barometric Pressure Alarm. . . . . . . . . . . . . . . . . . . . . . . . . . 48

Setting the Dew-Point Alarm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

To Silence an Alarm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

To Clear an Alarm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

E

NABLING

/D

ISABLING

A

UTO

C

LEAR

. . . . . . . . . . . . . . . . . . . . . . 50

G

ENERAL

H

IGH

/L

OW

C

LEAR

. . . . . . . . . . . . . . . . . . . . . . . . . . . 50

To Use General Clear Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

C

ALIBRATION

N

UMBERS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Inside and Outside Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Wind Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Rainfall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Changing Calibration Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Resetting Calibration Numbers to Default . . . . . . . . . . . . . . . . . . . . . . . 53

D

ISPLAY

S

CAN

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Starting the Scan Routines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Stopping a Scan Routine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

P

RIMARY

P

OWER

AND

B

ATTERY

B

ACKUP

I

NDICATORS

. . . . . . . . . 54

Table of Contents Page iv

Energy EnviroMonitor Manual Page 1

Chapter

1

I

NTRODUCTION

TO THE

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For use by fuel distributors, planners, and utilities, the Energy EnviroMonitor
(Energy EM) measures weather conditions which aid in estimating fuel oil con­sumption, heating and cooling energy requirements at a development site, and
solar and wind energy potentials at a collection site. This integrated weather
station, computer, and data logger measures/calculates, displays, and stores
heating and cooling degree-days, temperature-humidity index cooling degree­days, wind chill heating degree-days, temperature, temperature-humidity
index, wind chill, wind speed, wind run, wind direction, solar radiation, solar
energy, rainfall, rate of rainfall, barometric pressure, relative humidity, and
dew-point. Current values, high and low values, cumulative totals, and daily
averages are available for display at the push of a button. The system can even
sound an alarm when values exceed a threshold set by the user.

O

PTIONAL

S

ENSORS

The following optional sensors enable the Energy EM to measure and calculate
specialized weather information. All optional sensors are available from your
dealer or may be ordered directly from Davis Instruments.

• Anemometer

Enables you to measure and display wind speed, wind run, wind direc­tion, wind chill, and wind-chill degree-days (with temperature sensor).

Introduction to the Energy EnviroMonitor

Page 2 Energy EnviroMonitor Manual

• External Temperature Sensor

Enables you to measure and display outside temperature, and heating
and cooling degree-days.

Note: You may use EITHER the external temperature sensor, external temperature/humidity sen-

sor, or the stainless steel temperature probe.

• External Temperature/Humidity Sensor

Enables you to measure and display outside temperature, outside
humidity, dew-point, temperature-humidity index, normal and temper­ature-humidity index cooling degree-days, and heating degree-days.
(See note in external temperature sensor section for restrictions.)

• Rain Collector

Enables you to measure and display daily and total rainfall and rate of
rainfall. Separate models measure rainfall in either 0.01-inch or 0.2-mm
increments. Optional Rain Collector Heater enables you to measure the
moisture content of snowfall or freezing rain.

• Solar Radiation Sensor

Enables you to measure and display solar irradiance and incident
energy.

• Stainless Steel Temperature Probe

Enables you to measure and outside temperature and growing degree­days or soil temperature. Rugged stainless-steel construction makes sen­sor ideally suited to measuring soil or water temperature. (See note in
external temperature sensor section for restrictions.)

O

PTIONAL

A

CCESSORIES

The following accessories, designed for use with the Energy EM, are available
from your dealer or may be ordered directly from Davis Instruments.

• Energy WeatherLink

®

Logs data gathered by the Energy EM, downloads it to your PC, and
generates reports and graphical displays. Storage interval (1, 5, 10, 15, 30,
60, or 120 minutes) is set by the user. The data logger will store 16 hours
or 3, 7, 10, 21, 42, or 85 days worth of data depending on storage interval.
Windows

™

-compatible software enables you to analyze, plot, print, sort,
and summarize the data. Includes fuel customer management feature.
Automatically generates NOAA reports. Print and export degree-day
information totaled for the day and month.

• Sensor Mounting Arm

A single-location mounting option. The Sensor Mounting Arm includes
provisions for optimal mounting of all Davis sensors: anemometer, tem­perature sensor (with Radiation Shield), solar radiation sensor, Rain Col­lector Shelf, etc.

Optional Accessories

Energy EnviroMonitor Manual Page 3

• Sensor Tilting Bracket

Enables you to adjust the position of the solar radiation sensor to match
the angle of the sun’s rays for maximum readings.

• Radiation Shield

Protects the temperature sensor or temperature/humidity sensor from
solar radiation and other sources of radiated and reflected heat.
Increases the life of the sensor and the accuracy of the readings.

• Rain Collector Shelf

Provides a horizontal surface for mounting the rain collector. May be
used with Sensor Mounting Arm or mounted on other surfaces.

• Shelters

We have a pair of weather-resistant shelters which will enable you to
mount some or all of your system components outside. Optional heaters
enable you to keep components operating even in cold weather.

• Solar Power Kit

Powers the weather station using energy from the sun; no AC power is
required. Requires our 6.5-Amp-Hour Battery or other battery of your
choice.

• Alarm Output Module

Enables you to use weather station alarms to automatically start or stop
external devices such as irrigation systems, heaters, or fans.

• Surge Protectors

For upgraded protection against lightning-induced power surges,
power-cross conditions, and ground potential rises, use Surge Protec­tors. Use one Surge Protector for every two wires and mount inside one
of our surge-protector shelters.

Introduction to the Energy EnviroMonitor

Page 4 Energy EnviroMonitor Manual

Energy EnviroMonitor Manual Page 5

Chapter

2

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NERGY

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O

VERVIEW

THE K

EYBOARD

The Energy EM’s keyboard contains two different types of keys: function keys
and operation keys. The larger and more square keys ar e the function keys and
are used to display the various conditions measured and calculated by the
Energy EM. The smaller and more rounded keys are operations keys and are
used to view or use the various features of the Energy EM.

Energy EnviroMonitor Overview

Page 6 Energy EnviroMonitor Manual

W

EATHER

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ONDITIONS

M

EASURED

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ALCULATED

This section outlines each of the weather conditions measured/calculated by
the Energy EM. Each section includes a brief discussion of the weather condi­tion and a listing of the various ways in which the unit displays or stores that
condition. Be aware that some of the weather conditions require an optional
sensor in order to measure/calculate a value (see “Optional Sensors” on
page 1). If you do not have the required sensor that reading will appear as a
series of dashes in the Energy EM display.

Values which are described as “Daily” readings will provide true daily read­ings only if they are cleared each day. You may clear these values yourself or
use AutoClear (see “AutoClear” on page 12) to clear them for you. If you do
not clear the values every day, then you can use the “daily” readings to repre­sent any interval you desire: two days, one week, one month, etc.

The notation “(AutoClear)” next to a weather condition indicates that the
Energy EM’s AutoClear function may clear the weather condition at a set time
every day. For information on AutoClear, see “AutoClear” on page 12.

The notation “(Alarm:)” next to a weather condition indicates that an alarm
exists for the weather condition. The type of alarms are noted after the colon.
For information on Alarms, see “Alarms” on page 14.

Cooling Degree-Days

Cooling degree-days provide a measure for calculating the effect of tempera­ture on the use of energy to cool a location. Because temperature plays an
important part in the use of energy to cool a house or other structure, a mea­surement which takes into account the accumulation of heat with passing time
is necessary to predict usage. One cooling degree-day accumulates when the
temperature remains one degree above the thr eshold for 24 hours. One cooling
degree day also accumulates when the temperature remains 24˚ above the
threshold for 1 hour. The Energy EM calculates both normal cooling degree­days and temperature-humidity index cooling degree-days. Temperature­humidity index cooling degree-days uses apparent temperature (see “Temper­ature and Apparent Temperature” on page 7) instead of outside temperature
when calculating cooling degree-days.

• “Daily” Cooling Degree-Days Sum (AutoClear)

• Cooling Degree-Days Total for the period (Alarm: High/Low)

• Average daily Cooling Degree-Days over the period

• “Daily” T/H Index Cooling Degree-Days Sum (AutoClear)

• Cooling T/H Index Degree-Days Total for the period (Alarm: High/Low)

• Average daily T/H Index Cooling Degree-Days over the period

Weather Conditions Measured/Calculated

Energy EnviroMonitor Manual Page 7

Heating Degree-Days

Heating degree-days provide a measure for calculating the effect of tempera­ture on the use of energy to heat a location. Essentially the opposite of cooling
degree-days, heating degree-days take into account the accumulation of cold
with passing time to calculate energy usage. One heating degree-day accumu­lates when the temperature remains one degree below the threshold for 24
hours. One heating degree day also accumulates when the temperature remains
24˚ below the threshold for 1 hour. The Energy EM calculates both normal heat­ing degree-days and wind chill heating degree-days. Wind chill heating
degree-days uses apparent temperature (see “Temperature and Apparent Tem­perature” on page 7) instead of outside temperature when calculating heating
degree-days.

• “Daily” Heating Degree-Days Sum (AutoClear)

• Heating Degree-Days Total for the period (Alarm: High/Low)

• Average Daily Heating Degree-Days over the period

• “Daily” Wind Chill Heating Degree-Days Sum (AutoClear)

• Wind Chill Heating Degree-Days Total for the period (Alarm: High/Low)

• Average Daily Wind Chill Heating Degree-Days over the period

Temperature and Apparent Temperature

The Energy EM has a temperature sensor built into the console which reports
inside temperature. You may use either the external temperature sensor, stain­less steel temperature probe, or external temperature/humidity sensor (see
“Optional Sensors” on page 1) to measure outside temperature. Outside tem­perature does not necessarily have to measure outside temperature, of course.
It measures the air temperature wherever you have located your temperature
sensor.

Temperature-humidity index (T-H index), commonly called heat stress, uses
the temperature and the relative humidity to determine how hot the air tem­perature actually “feels.” When humidity is low, the apparent temperature will
be cooler than the air temperature since perspiration can rapidly evaporate into
the air. However, when humidity is high (i.e., the air is saturated with water
vapor) the apparent temperature will be higher than the air temperature.

Note: The Energy EM measures T -H index only when air temperature is above 68˚ F (20˚ C) because it is

a measure of heat stress which is not significant at lower temperatures. 125˚ F (52˚ C) is the high­est T-H index for which calculation factors are available. Above 125˚ F (52˚ C), the system simply
reports that T-H index is “high.”

Energy EnviroMonitor Overview

Page 8 Energy EnviroMonitor Manual

Wind chill takes into account how the speed of the wind affects our perception
of the air temperature. The body warms up the air molecules which surround it
by transferring heat from the skin to the surrounding air. If the wind is com­pletely still, this “insulating layer” of warm air molecules stays next to the
body, offering some protection from the cooler air molecules and limiting fur­ther transfer of heat. When the wind is blowing, however, the warm air sur­rounding the body is swept away. The faster the wind blows, the faster the heat
is carried away and the colder you feel.

• Current Outside Temperature (Alarm: High/Low)

• Current T-H Index (Alarm: High)

• Current Wind Chill (Alarm: Low)

• Current Inside Temperature (Alarm: High/Low)

• “Daily” High and Low Outside Temperature with time of occurrence (AutoClear)

• “Daily” High T/H Index with time of occurrence (AutoClear)

• “Daily” Low Wind Chill with time of occurrence (AutoClear)

• “Daily” High and Low Inside Temperature with time of occurrence (AutoClear)

Wind

The Energy EM measures wind speed, wind direction, and wind run. W ind run
is a measurement of the “amount” of wind which passes a given point (the ane­mometer) during the measurement period. It is expressed as either “miles of
wind” or “kilometers of wind” and is determined by calculating the integral
(summation) of wind speed multiplied by the time of the measurement period.
For example, if the wind blew at an absolutely steady 10 MPH for 12 hours,
you would have 120 miles of wind run (speed x time = 10 MPH x 12 Hours =
120 miles). Wind speed changes over time, so wind r un is calculated by adding
together (summing) the distance (speed x time) for every single speed and time
reading during the measurement period. In practice, however, the Energy EM
simply keeps count of the number of revolutions made by the wind cups dur­ing the period and multiplies that number by a scale factor which gives a wind
run reading in either miles or kilometers.

• Current Wind Speed (Alarm: High)

• “Daily” Wind Run (Auto Clear)

• Average Daily Run during period

• Wind Direction (in compass rose only)

• High Wind Speed with direction of high and time of occurrence (AutoClear)

Weather Conditions Measured/Calculated

Energy EnviroMonitor Manual Page 9

Solar Radiation

What we call “current solar radiation” is technically known as Global Solar
Radiation, a measure of the intensity of the sun’s radiation reaching the earth’s
surface. This irradiance includes both the direct component from the sun and
the diffuse component from the rest of the sky. The solar radiation reading
gives a measure of the amount of solar radiation hitting the solar radiation sen­sor at any given time, expressed in Watts per Square Meter (W/m

2

). The power
of this radiation, when integrated (summed) over a period of time, gives a
measure of the amount of incident solar energy received during that time
period. This solar energy reading is expressed in Langleys.

Note: The Energy EM measures energy received in the spectral band between 400 and 1100 nm.

• Current Solar Radiation Intensity

• “Daily” Incident Solar Energy Sum (AutoClear)

• Average Incident Solar Energy per day during period

Rainfall

The Energy EM provides two separate registers for tracking rainfall totals. One
is referred to as “daily” rainfall and the other is referr ed to as “total” rainfall. In
truth, these registers can be used to recor d rainfall over any period of time you
desire. The “daily” register can be cleared daily using the AutoClear function
(see “AutoClear” on page 12) to provide true daily rainfall totals or you may
clear it manually every few days, after a storm, at the end of the month, etc.
The total rainfall amount must be cleared manually and how often you clear
the register determines what period of time its rainfall total reflects. The
Energy EM also calculates the rate of rainfall using the amount of time between
each .01" or .2 mm rainfall increment.

• “Daily” Rainfall (Alarm: High) (AutoClear)

• Current Rate of Rainfall in inches or millimeters per hour

• Total Rainfall

• Maximum Rate of Rainfall with time of occurrence

1 Langley = 41.84 kiloJoules per square meter
= 11.622 Watt-hours per square meter
= 3.687 BTUs per square foot

Energy EnviroMonitor Overview

Page 10 Energy EnviroMonitor Manual

Barometric Pressure

The weight of the air which makes up our atmosphere exerts a pressure on the
surface of the earth. This pressure is known as atmospheric pressure. Gener­ally, the more air above an area, the higher the atmospheric pressure, which
means that atmospheric pressure changes with altitude. To compensate for this
difference and facilitate comparison between locations with different altitudes,
atmospheric pressure is generally adjusted to the equivalent sea-level pressur e.
This adjusted pressure is known as barometric pressure. In reality, the
Health EM measures atmospheric pressure. When you enter the barometric
pressure for your location (see “Entering Barometric Pr essur e” on page 37), the
Health EM stores the necessary offset value to consistently translate atmo­spheric pressure into barometric pressure.
Barometric pressure also changes with local weather conditions, which makes
barometric pressure an extremely important and useful weather forecasting
tool. High pressure zones are generally associated with fair weather while low
pressure zones are generally associated with poor air. For forecasting purposes,
however, the absolute barometric pressure value is generally less important
than the change in barometric pressure. In general, rising pressure indicates
improving weather conditions while falling pressure indicates deteriorating
weather conditions.

• Current Barometric Pressure (Alarm: rate of change)

• Trend of Barometric Pressure (rising, falling, steady) over previous one hour

Humidity

Humidity itself simply refers to the amount of water vapor in the air. However,
the amount of water vapor which the air can contain varies with changes in air
temperature and pressure. Relative humidity takes into account these factors
and offers a humidity reading which reflects the amount of water vapor in the
air as a percentage of the amount the air is capable of holding. Relative humid­ity, therefore, is not actually a measure of the amount of water vapor in the air,
but a ratio of the air’s water vapor content to its capacity.

It is important to realize that relative humidity changes with temperature, pr es­sure, and water vapor content. If you have a parcel of air with a capacity for
10 g of water vapor which contains 4 g of water vapor, the relative humidity
would be 40%. Adding 2 g more water vapor (for a total of 6 g) would change
the humidity to 60%. If that same parcel of air is them warmed so that it has a
capacity for 20 g of water vapor, the relative humidity drops to 30% even
though water vapor content does not change.

• Relative Humidity (Alarm: High/Low)

• “Daily” High and Low Relative Humidity with time of occurrence (AutoClear)

Period

Energy EnviroMonitor Manual Page 11

Dew-Point

Dew-point is the temperature to which air must be cooled for saturation (100%
relative humidity) to occur, providing there is no change in water content. The
dew-point is an important measurement used to predict the formation of dew,
frost, and fog. If dew-point and temperature are close together in the late after­noon when the air begins to turn colder, fog is likely during the night. Dew­point is also a good indicator of the air’s actual water vapor content (as
opposed to relative humidity). High dew-point indicates high vapor content;
low dew-point indicates low vapor content. You can even use dew-point to
predict the minimum overnight temperature. Provided no new fronts are
expected overnight, the afternoon’s dew-point gives you an idea of what mini­mum temperature to expect that night, since the air is not likely to get colder
than the dew-point anytime during the night.

• Current Dew-Point (Alarm: when temperature is within 2˚F of dew-point)

Time

The GroWeather has a clock and a calendar for tracking time and date. The cal­endar automatically adjusts during leap years, providing you enter the current
year (see “Entering Time, Date, or Year” on page 42) when you apply power to
the unit.

• Current Time (Alarm: standard)

• Current Date

• Current Year

• AutoClear Time Setting

• Period Information

P

ERIOD

The Energy EM uses a single time period for all values which accumulate totals
or calculate daily averages over an interval. Beginning a new period clears all
data from the previous period. The system stores the beginning date of the
period, which you may display along with the number of days which have
elapsed since the beginning of the period.

Note: The system records the start time of the period to the nearest 90 minutes. Therefore, all average val-

ues are exact to the nearest 90-minute mark throughout the period. However, averages calculated
during the period are most accurate when the period length is an exact number of days (that is, if
you display the average at the same time of day at which the period started). When the length of the
period is displayed, the Energy EM rounds down to the nearest whole day COMPLETED.

The following values are accumulated or averages calculated during the
period. Note that averages are not displayed (i.e., a series of dashes appears
instead) until at least one day has elapsed.

• Total Cooling Degree-Days

Energy EnviroMonitor Overview

Page 12 Energy EnviroMonitor Manual

• Average Daily Cooling Degree-Days

• Total T-H Index Cooling Degree-Days

• Average Daily T-H Index Cooling Degree-Days

• Total Heating Degree-Days

• Average Daily Heating Degree-Days

• Total Wind Chill Heating Degree-Days

• Average Daily Wind Chill Heating Degree-Days

• Average Daily Wind Run

• Average Solar Energy per day

A

UTO

C

LEAR

The Energy EM’s AutoClear function may be used to automatically clear some
or all of the “daily” values at the same time each day. The time at which values
are cleared is the same for all values and may be set by the user (default is mid­night). The AutoClear function may be enabled/disabled individually for the
values listed below. Note that the AutoClear function for some values (for
example, high wind speed and “daily” wind run) is linked; you may enable or
disable the AutoClear for all linked values, not for each individual value. The
list below shows all values which may be cleared using AutoClear. Those listed
together must be cleared as a group.

• “Daily” Cooling Degree-Days

• “Daily” Heating Degree-Days

• High and Low Outside Temperature, High Temp/Hum Index, Low Wind Chill, High
and Low Inside Temperature

• High Wind Speed and “Daily” Wind Run

• “Daily” Solar Energy

• “Daily” Rainfall and High Rate of Rainfall

• High and Low Outside Humidity