Steel Mill Version Only - MSA ALTAIR Pro H2S Manual De Operación

5) Time Weighted Average, TWA.
• The TWA reading displays what the instrument has calculated
since power-ON.
• When this page displays, press the TEST button to clear.
• "CLR" displays
• TWA value is automatically reset to zero when the instrument is
turned ON.
• TWA value is calculated over an eight-hour exposure
• The following formula is used to calculate the TWA value:
• If the instrument is ON for less than 8 hours (480 minutes), the
balance of the minute ppm values is set to zero,
6) IR mode.
• When instrument displays "IR?", press button to enter IR mode.
• If IR communications are not detected for three minutes or the
TEST button is pressed, the instrument will exit this mode.
• See FIGURE 2-5 for additional details.

Steel Mill Version Only:

1) Test g as mode
2) Functional check of LCD, vibrator, LEDs and horn
3) Software version displays.
4) Gas type
5) Low Alarm setpoint ("LO" "Alarm")
6) High Alarm setpoint ("HI" "Alarm")
7) STL Alarm setpoint
8) TWA Alarm setpoint
9) Peak Reading
• Toxic ("HI")
• The Peak/Hi and Min/Low values can be cleared.
• When this page is displayed, press the TEST button to clear.
• "CLR" displays.
10) Short Term Ex posure Limit, STL
• The STL reading displays that the instrument calculated since
power-ON.
• When this page displays, press the TEST button to clear.
• "CLR" displays.
2-14
Sum of 1-minute gas readings/ 480 minutes (8 hours) = TWA value