OPERATION MANUAL HEAT INDEX WBGT METER 8758 Model: 8778 8758 8778
INTRODUCTION Thank you for purchasing the Heat Index WBGT meter. The handy meter measures air temperature, globe temperature, and humidity to give heat stress index for using in control of physical activity in hot environment to limit the danger of heatrelated injuries WBGT(wet-bulb globe temperature) was developed as a monitoring basis at US military training camps and became widespread for the use in workplaces and sports situations.
CONTROLS AND INDICATORS LCD display Symbol indication WBGT TG TA % C/F IN OUT Wet Bulb Globe Temperature Black Globe Temperature Air Temperature Relative Humidity Celsius/Fahrenheit Indoor (no sun) Outdoor (full sun) Low battery indicator DP/REC Vain icons in these models.
OPERATING INSTRUCTIONS 1. POWER ON/OFF Press to turn on and turn off the meter. All indicators are shown on the LCD when power on, and then enter measuring mode. 2. MEASUREMENT Slide down the protecting sheath of sensor before measurements. Pull up to protect sensor Design patent pending Select display mode The meter measures TA(Air Temp), TG (Globe Temp.), RH (Relative Humidity), and calculates WBGT. Press to select modes. An icon shows on the top to indicate the current operation mode. (Fig.
3. ALARM SETTING The meter features audible alarm to give warning for possible heat stress in the environment. When WBGT value reaches the alarm threshold, the value starts to blink with continuous beep(about 70 dB). The alarm stops when measured value falls below the threshold or the meter is turned off. The alarm threshold is adjustable for different applications. Hold down for 2 seconds to turn on the meter and enter alarm setting. The current setting displays with a blinking digit.
5. AUTO POWER OFF The meter turns off automatically after 20 minutes non-operation. To override the function, hold down and for 2 seconds to turn on the meter. The LCD will display “n” and then enter measuring mode. (Fig. C) MODE Fig. C 6. TRIPOD MOUNTING The meter can fit on a tripod for long time monitoring. A built-in thread is on the rear side of the meter. RH CALIBRATION The meter can be calibrated on the humidity by end users with 33% and 75% salt solution.
Salt solution Pic.A1 33% calibration Plug the sensor probe into 33% salt bottle(Pic A1),hold down , ,and buttons for 2 seconds to power on the meter until blinking “3X.X%” appears. Meter is now calibrating, and will finish in about 60 mins. when the value stops blinking. MODE NEXT Note: Strongly recommend to use one hand to press one button, and use two fingers of the other hand to press two buttons simultaneously . This is easier for you to operate 3 keys.
CAUTION: Reassemble the globe with caution by fitting the pin (Pic. B) into the connector (Pic.C). It helps to position by targeting the screw holes on the sheath and the meter. Incorrect installation may damage the sensor. Sensor pin Pic.B Important: Screw holes for targeting to assemble the globe. Sensor connector Pic. D Pic.C TROUBLESHOOTING ? Power on but no display Check whether the batteries are in good contact and correct polarity, or take out the batteries for one minute and reinstall and retry.
RS232 INTERFACE The meter can do PC link for on-line logging and data analysis via RS232 interface and software. The protocol is as follows. A.9600 bps, 8 data bits, no parity. B.Format (Transmitting ASCII code by every second while meter is on.) Wxxx.xC(F):Txxx.xC(F):Txxx.xC(F) :Hxx.x%LRCCRLF Note: The 1st value is WBGT, the 2nd is TA, the 3rd is TG, and the 4th is RH. SPECIFICATION 8758 Black ball size 8778 Air Temp. range 40(D)x35(H)mm 75(D)x75(H)mm 0~50℃ (32~122℉) Air Temp. accuracy ±0.
MATERIALS SUPPLIED This package contains: Meter 2pcs AAA batteries Operation manual Plain box packaging Optional accessory: 33% calibration salt (HR33) 75% calibration salt (HR75) RS232 cable and software(ASFTKIT) WARRANTY The meter is warranted to be free from defects in material and workmanship for a period of two years from the date of purchase. This warranty covers normal operation and does not cover misuse, abuse, alteration, neglect, improper maintenance, or damage resulting from leaking batteries.
APPENDIX Recommendations to heat exposure level for working and physical activity! PERMISSIBLE HEAT EXPOSURE THRESHOLD LIMIT Value:WBGT Work/rest regimen Light Moderate Heavy 26.7 o C /80 o F 28 o C /82 o F 29.4 o C /85 o F 31.1 o C /88 o F 25 o C /77 o F 25.9 o C /78 o F 27.9 o C /82 o F 30 o C /86 o F (Each hour) Continuous work 75% work, 25% rest 50% work, 50% rest 25% work, 75% rest 30 o C /86 o F 30.6 o C /87 o F 31.4 o C /89 o F 32.
