About product

Hygrographs M-21A daily and weekly are intended to measure and record the relative humidity of air in terrestrial conditions, they are made for the needs of the national economy, exploited at temperatures from minus 35 to plus 45°C.

Tactical characteristics

Variations of readings of hygrograph, %

No more than 6

Time of establishment of indications

of a hygrograph, seconds

Not more than 300

Instant daily move hour

mechanism at a temperature of (20±5)°С

Not more than ±5

Instantaneous change

diurnal variation caused

temperature change

ambient air in the range

working temperatures, %/°С

Not more than ±3

Deviation of the line for recording

a small horizontal division of the form

from the vertical when the pen is moved

along the entire height of the working part

of the form for the hygrograph:

- daily

- weekly

No more than 1/3

No more than 1/4

Record line width:

- within normal conditions, m

- at a deviation from

normal conditions, mm

0,3 +0,1/-0,2

Not more than 0,6

General characteristics

  • Hygrograph dimensions 335×240×180mm
  • Hygrograph mass 2.5 kg
  • The hygrograph uptime probability for 1000 hours of operating time 0.94
  • Average service life 8 years

Additional information

The device has got the measuring tools type approval certificate. State register number 15114-96.