Campbell Scientific BlackGlobe Temperature Sensor for Heat Stress User Manual

BlackGlobe Temperature
Sensor for Heat Stress
Revision: 9/13
Campbell Scientific, Inc.
Copyright © 2013

Warranty

“PRODUCTS MANUFACTURED BY CAMPBELL SCIENTIFIC, INC. are warranted by Campbell Scientific, Inc. (“Campbell”) to be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless otherwise specified in the corresponding Campbell pricelist or product manual. Products not manufactured, but that are re-sold by Campbell, are warranted only to the limits extended by the original manufacturer. Batteries, fine-wire thermocouples, desiccant, and other consumables have no warranty. Campbell’s obligation under this warranty is limited to repairing or replacing (at Campbell’s option) defective products, which shall be the sole and exclusive remedy under this warranty. The customer shall assume all costs of removing, reinstalling, and shipping defective products to Campbell. Campbell will return such products by surface carrier prepaid within the continental United States of America. To all other locations, Campbell will return such products best way CIP (Port of Entry) INCOTERM® 2010, prepaid. This warranty shall not apply to any products which have been subjected to modification, misuse, neglect, improper service, accidents of nature, or shipping damage. This warranty is in lieu of all other warranties, expressed or implied. The warranty for installation services performed by Campbell such as programming to customer specifications, electrical connections to products manufactured by Campbell, and product specific training, is part of Campbell’s product warranty. CAMPBELL EXPRESSLY DISCLAIMS AND EXCLUDES ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Campbell is not liable for any special, indirect, incidental, and/or consequential damages.”

Assistance

Products may not be returned without prior authorization. The following contact information is for US and international customers residing in countries served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs for customers within their territories. Please visit
www.campbellsci.com to determine which Campbell Scientific company serves
your country.
To obtain a Returned Materials Authorization (RMA), contact CAMPBELL SCIENTIFIC, INC., phone (435) 227-9000. After an applications engineer determines the nature of the problem, an RMA number will be issued. Please write this number clearly on the outside of the shipping container. Campbell Scientific’s shipping address is:
CAMPBELL SCIENTIFIC, INC. RMA#_____ 815 West 1800 North Logan, Utah 84321-1784
For all returns, the customer must fill out a “Statement of Product Cleanliness and Decontamination” form and comply with the requirements specified in it. The form is available from our web site at www.campbellsci.com/repair. A completed form must be either emailed to repair@campbellsci.com or faxed to (435) 227-9106. Campbell Scientific is unable to process any returns until we receive this form. If the form is not received within three days of product receipt or is incomplete, the product will be returned to the customer at the customer’s expense. Campbell Scientific reserves the right to refuse service on products that were exposed to contaminants that may cause health or safety concerns for our employees.

Table of Contents

PDF viewers: These page numbers refer to the printed version of this document. Use the PDF reader bookmarks tab for links to specific sections.
1. Introduction.................................................................1
2. Cautionary Statements............................................... 1
3. Initial Inspection .........................................................1
3.1 Ships With List.....................................................................................1
4. Overview......................................................................2
5. Specifications .............................................................2
5.1 Accuracy ..............................................................................................2
6. Installation...................................................................4
6.1 Siting ....................................................................................................4
6.2 Assembly and Mounting ......................................................................4
6.2.1 Mounting the BlackGlobe on the Mounting Arm .........................4
6.2.2 Mounting the BlackGlobe Assembly on a Horizontal
Crossarm....................................................................................6
7. Operation.....................................................................7
7.1 Wiring ..................................................................................................7
7.2 Calculations..........................................................................................8
7.2.1 Wet-Bulb Globe Thermometer Index (WBGT)............................8
7.2.2 Dewpoint.......................................................................................8
7.2.3 Vapor Pressure ..............................................................................9
7.2.4 Saturated Vapor Pressure ..............................................................9
7.2.5 Wet-Bulb.......................................................................................9
7.2.6 Mean Site Barometric Pressure Calculation (SP_kPa)................10
7.3 Programming......................................................................................10
7.3.1 Example CR1000 Program .........................................................10
7.4 Long Lead Lengths ............................................................................12
8. Maintenance ..............................................................12
9. References ................................................................12
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Table of Contents
Appendices
The Theory of BlackGlobe Temperature and
A.
Heat Stress ............................................................A-1
B. Edlog Programming Examples ..............................B-1
B.1 Example CR10X Program............................................................... B-1
B.2 Edlog Programming for Long Lead Lengths................................... B-9
Figures
5-1. Polynomial error curve (Edlog dataloggers only)................................ 3
5-2. Thermistor interchangeability limits ................................................... 4
6-1. Mounting kit components.................................................................... 5
6-2. Nuts and lock washers on mounting bolt............................................. 5
6-3. BlackGlobe fitting and cable alignment .............................................. 6
6-4. BlackGlobe mounted to a crossarm (front view)................................. 7
6-5. BlackGlobe mounted to a crossarm (back view)................................. 7
Tables
5-1. Thermistor Interchangeability Specification ....................................... 3
5-2. Polynomial Error ................................................................................. 3
7-1. Wiring Diagram for Campbell Scientific Dataloggers ........................ 8
A-1. Sample use of WBGT Index............................................................ A-1
B-1. Polynomial Coefficients .................................................................. B-7
B-2. Actual Temperature, Sensor Resistance, and Computed
Temperature................................................................................. B-7
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BlackGlobe Temperature Sensor for Heat Stress

1. Introduction

The BlackGlobe Temperature Sensor for Heat Stress (BlackGlobe) measure radiant temperature. This measurement, along with the measurement of ambient air and wet-bulb temperatures, is used to calculate the wet-bulb globe temperature (WBGT). The WBGT index combines the effects of temperature, humidity, radiant heat, and wind into one single index employed to express environmental heat stress. The measurement of heat stress is important because loss of physical and mental efficiency occurs under definable degrees of heat stress. Severe heat stress can lead to fatigue, exhaustion and possibly even disability or death.
Before installing the BlackGlobe, please study
Section 2, Cautionary Statements
Section 3, Initial Inspection

2. Cautionary Statements

The BlackGlobe is a precision instrument. Please handle it with care.
The black outer jacket of the cable is Santoprene® rubber. This
compound was chosen for its resistance to temperature extremes, moisture, and UV degradation. However, this jacket will support combustion in air. It is rated as slow burning when tested according to U.L. 94 H.B. and will pass FMVSS302. Local fire codes may preclude its use inside buildings.
Do not use the BlackGlobe with long lead lengths in an electrically noisy
environment.

3. Initial Inspection

Upon receipt of the BlackGlobe, inspect the packaging and contents for
damage. File damage claims with the shipping company. Immediately check package contents against the shipping documentation (see Section
3.1, Ships With List). Contact Campbell Scientific about any discrepancies.
The model number and cable length are printed on a label at the
connection end of the cable. Check this information against the shipping documents to ensure the expected product and cable length are received.

3.1 Ships With List

(4) 7362 8 inch Wire Ties
(1) 29956 BlackGlobe Mounting Kit
ResourceDVD
1
BlackGlobe Temperature Sensor for Heat Stress

4. Overview

The BlackGlobe uses a thermistor inside a 15.24 cm (6 in) hollow copper sphere, painted black to measure radiant temperature. This measurement along with the measurement of ambient air and wet-bulb temperatures may be used to calculate the WBGT index, which is sometimes referred to as the Humidex.
Sensor cable length is specified at the time of order. Do not exceed 1000 feet of cable.
To calculate the wet-bulb globe thermometer index (WBGT), the measurement of the BlackGlobe (radiant heat), wet-bulb (evaporative heat), and ambient air (dry-bulb) temperatures are required. The wet-bulb temperature can be calculated using air temperature and relative humidity if a wet-bulb thermometer is not available. See Section 7.2, Calculations.

5. Specifications

Temperature Measurement Range: –5° to +95°C
Temperature Survival Range: –50° to +100°C
NOTE

5.1 Accuracy

Thermistor Interchangeability Error: Typically < ±0.2°C over 0°C to 70°C
and ±0.3 at 95°C
Polynomial Linearization Error: < ±0.5°C over –7°C to +90°C
Near Normal Emittance: 0.957
Maximum Cable Length: 305 m (1000 ft)
The black outer jacket of the cable is Santoprene compound was chosen for its resistance to temperature extremes, moisture, and UV degradation. However, this jacket will support combustion in air. It is rated as slow burning when tested according to V.L. 94 H.B. and will pass FMVSS302. Local fire codes may preclude its use inside buildings.
The overall probe accuracy is a combination of the thermistor’s interchangeability specification, the precision of the bridge resistors, and the Steinhart-Hart equation error (CRBasic dataloggers) or the polynomial error (Edlog dataloggers). In a worst case, all errors add to an accuracy of ±0.3°C over the range of –3° to 90°C and ±0.7°C over the range of –5° to 95°C. The major error component is the interchangeability specification of the thermistor, tabulated in TABLE 5-1 and plotted in FIGURE 5-2. For the range of 0° to 50°C, the interchangeability error is predominantly offset and can be determined with a single point calibration. Compensation can then be done with an offset entered in the measurement instruction. The bridge resistors are
0.1% tolerance with a 10 ppm temperature coefficient. Polynomial errors are tabulated in TABLE 5-2 and plotted in FIGURE 5-1.
@
rubber. This
2
BlackGlobe Temperature Sensor for Heat Stress
TABLE 5-1. Thermistor
Interchangeability Specification
Temperature (°C)
5
Temperature Tolerance (±°C)
0.14
0 to +70 0.10
+85 0.25
+95 0.35
TABLE 5-2. Polynomial Error
–5° to +95° < ±0.5°C
–3° to +90° < ±0.1°C
FIGURE 5-1. Polynomial error curve (Edlog dataloggers only)
3
BlackGlobe Temperature Sensor for Heat Stress

6. Installation

Thermistor Interchangeability Limits
0.3
0.25
0.2
0.15
0.1
T
error
T
error
_therm_pos
_therm_neg
0.05
0
-0.05
-0.1
-0.15
-0.2
-0.25
-0.3
-5 10 25 40 55 70 85 100
T
FIGURE 5-2. Thermistor interchangeability limits

6.1 Siting

The BlackGlobe must be mounted in a location that will not be shadowed and is representative of the environmental conditions to be measured.

6.2 Assembly and Mounting

Tools required for installing on a tripod or tower:
Adjustable end wrench or 7/16 in. and 1/2 in. open end wrench
Small screwdriver provided with the datalogger
Small pair of diagonal-cutting pliers
UV resistant cable ties provided with the BlackGlobe

6.2.1 Mounting the BlackGlobe on the Mounting Arm

The BlackGlobe and mounting kit (pn 29956) requires some assembly before installation. The mounting kit comes with (see Figure 6.1):
Mounting arm
Mounting bolt
Two lock washers
Two nuts
Two pipe clamps (not used when mounted to a horizontal pipe cross
arm)
U-bolt with associated nuts and washers
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