Setting Passwords - YOKOGAWA ZR22G User Manual

Since the gas-pressure ratio is equal to the volume ratio, the above equation may be expressed
mathematically by:
U = P x H/ es x 100
where, P = Gas pressure
H = moisture content (volume ratio)
The saturated water vapor pressure es is determined by a gas temperature, so the relative
humidity can be obtained by entering the above parameters.
To obtain the dew point:
The dew point is the temperature at which a water vapor pressure in the moist air is equal to the
saturated water vapor pressure.
The water vapor pressure in the moist air can be obtained from the gas pressure ad volume ratio
(= pressure ratio), as given below.
e = P x H
where, e = water vapor pressure in moist air
P = gas pressure
H = Humidity (moisture content) (volume ratio)
Use the above equation to find the water vapor in the moist air, and use the theoretical equation
(JIS Z 8806) to obtain the temperature at which that water vapor is equal to the saturated water
vapor pressure.
Setting Measurement Gas Temperature
l
There are two ways of entering measurement gas temperatures: one is to measure actual gas
temperature using a two-wire temperature transmitter and the other is to enter the preset value
manually.
Set the measurement gas temperature as follows:
(1) Press the Setup key in the basic panel display to display the Execution/Setup display.
(2) Select Setup in the Execution/Setup display. The "Commissioning" (Setup) display then
appears.
(3) Select Others in that display and then the Exhaust gas setup shown in Figure 8.19.
(4) Point to the Temperature input mode and press the [Enter] key. Then the display for
selecting either "Preset" or "mA input," appears. Choose the desired one for your system
requirements.
(5) If you choose the "Preset," a display for entering numeric data then appears. Enter the
measurement gas temperature (see CAUTION).
(6) If you choose "mA-input," the Exhaust gas setup display shown in Figure 8.20 appears.
Enter temperatures at 4- and 20-mA outputs of the temperature transmitter from the numeric
data entry display (See CAUTION).
(7) If you use measurement gas temperature alarms, choose the "Alarm value of temperature"
and enter an alarm temperature from the numeric data entry display.
NOTE
• The critical temperature of the saturated water vapor pressure is 3748 C. If a gas
temperature exceeding 3708 C is entered, no correct calculation will be obtained.
• If an invalid value is set, no correct calculation will be obtained. Be sure to check allowable
temperature ranges of the temperature transmitter you use, and then enter the value
correctly.
<8. Detailed Data Setting>
IM 11M12A01-02E
8-20
16th Edition : Mar. 19, 2020-00