SOP for Digital Thermohygrometer

This Document describes (Standard Operating procedure) Sop for Operation and calibration of digital Thermohygrometer

Sop for Operation and calibration of digital Thermohygrometer

I. Purpose & Scope:

  • To provide the procedure for monitoring of Temperature by Digital thermohygrometer in Quality Control Department.
  • This procedure is applicable to all Quality Control Department for monitoring of temperature by Digital thermohygrometer

II. Responsibilities:

  • All Quality Control and Quality Assurance personnel’s shall be responsible to follow and implement this SOP.

III : Introduction and Procedural Part :

Health, Safety and Environment: 

  • Check that the instrument and surroundings are clean, if not, clean with lint free cloth.
  • Check and ensure that the equipment is kept upright on its stand or fixed on wall and display is legible.
  • Install the battery with correct polarity positioning.
  • Place the unit away from direct sunlight rain or extreme heat.
  • Peel off display Protective sheet.
  • Ensure that Hygro-Thermometer is calibrated.
  • Ensure that hygrometer sensor holder to desired place in the area.
  • The unit will perform self-test and display reading normally after 5 seconds.

Preliminary Check for Digital thermohygrometer :

  • Check and ensure that the equipment is clean and suitable for starting the operation. If it is not, clean with a lint free cloth.
  • Immediately intimate to maintenance department through Job Order if the environmental conditions is out of limit.

Basic Operation of digital Thermohygrometers : 

Setting of Time, Clock alarm, 12 / 24 hours time format :

  • Time setting is carried out by pressing “MODE” button for 2 second.
  • After beep, release the “ADJ “ key, this shall appear  flashing of minutes.
  • Press “ADJ” to adjust the time value.
  • Press Mode once to set hour time. Press “ADJ” to adjust the hour parameters.
  • Press “MODE” twice to set 12/ 24 hours time format
  • Press “MODE” again to set Month & Date to set the parameters and after setting it shall directed to hh: mm.
  • Press “MODE” and press “ADJ” twice to appear alarm on hh:mm format. Press “ MODE” key for 2 seconds to reset the hh:mm for alarm activation.
  • MODE switch the clock and alarm display mode/ set the current clock alarm clock 12 or 24 hr clock date.
  • ADJ adjust the value is set to the project.
  • MEMORY display memory in the highest & lowest temperature and humidity value/clear memory of the minimum and maximum temperature and humidity values.
  • For deactivation of alarm, press mode and adjust key till it removes alarm indication.

Minimum / Maximum reading memory:

  • Press (MAX/MIN) button to display maximum measured value, press the button once more to display minimum measured value, press the button again to return to normal display.
  • Press and hold (MAX / MIN) button until two bars “ – -” are displayed then release to reset memory.
  • Daily Reset Slide (DAILY RESET) switch to “ON” position to reset maximum / minimum memory automatically at actual value of temperature
  • Set the 0 C / 0 F Exchange by pressing (0 C / 0 F) button to change temperature unit.
  • Record the temperature at first half & second half of the day in respective areas of QC lab.

Maintenance :

  • Battery Replacement:  Replace the batteries when signal of low battery appears in the display or whenever required.

Calibration of digital thermohygrometer :

  • Calibration Frequency: Yearly
  • Calibrate the equipment from the outside party once in a year.
  • Note: If equipment does not comply with any of the calibration Parameters then follow the relevant procedure of equipment Breakdown.

IV: Annexure:

Annexure I      : Room temperature record.

Annexure- II   :  List of thermohygrometer with temperature



Room Temperature Record 

Name of Areas

Temperature  Limit  Not More than 25°C


Frequency of Monitoring First half & second half of the day
Digital Thermo hygrometer No.           


Date Time Temp.








Recorded By Checked By Remarks,

If Any





List of thermohygrometer with Temperature


Sr. No. Area Temperature
1 Chemical Laboratory Not More than 25°C
2 Instrument Laboratory Not More than 25°C
3 Wet Laboratory Not More than 25°C


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