Yokogawa GD40 Gas Density Detector - Manual (Page 50)

<3. Operation>
3-7
IM 11T3E1-01E
3.1.7 Checking the Analyzer for Performance
When the required parameters have been completely set, bring into operation all equipment
composing the measurement loop. Keep this equipment operating for a while. After making sure
there is no problem with the equipment, go into normal operation.
For reference, the following summarizes the setting functions (related to signals) of the GD402
analyzer that are used to obtain the optimum operating conditions.
[Functions Related to the Output Signal]
The output signal can be held at a value immediately before calibration or at a desired value dur-
ing calibration or at the setting/service level. This is to prevent the output signal from adversely
affecting the operation of the equipment configuring the measurement loop (default setting: the
output signal is held at the value immediately before).
[Functions Related to the High/Low Limit Alarm Contact Output]
Select the parameters for which the alarms are raised, and then set their respective high/low limit
setpoints. The analyzer transmits an alarm contact signal if any of these setpoints is exceeded.
(Define the voltage-free contacts and the state of contacts at the service level.)
[Functions Related to the FAIL Contact Signal]
If a FAIL state occurs, an appropriate message appears on the LCD display. For details on these
functions, see Chapter 11.
[Contact output of Hydrogen purity / Replacement meter]
According to switching of Replacement meter, the status of contact and display (LED) is changed
as following. (The status of contact output are to be set in Service level, CODE 05.)
• Hydrogen purity meter
RANGE FUNC SEL GAS LED
Replacement
Meter
H
2
in CO
2
AIR in CO
2
—
ACTIVE
NORMAL
ON
OFF
Hydrogen Purity/
Replacement Meter
H
2
in AIR
H
2
in CO
2
AIR in CO
2
NORMAL
ACTIVE
ACTIVE
NORMAL
ACTIVE
NORMAL
OFF
ON
OFF
FUNC: Identification signal of Hydrogen purity/Replacement Meter. (contact)
SEL GAS: Range identification signal of Replacement Meter. (contact)
[The status of contact output]
FAIL SEL FUNC MAINT ALM
Power Supply
OFF
OPEN CLOSE CLOSE CLOSE CLOSE
Power Supply
ON
NORMAL: CLOSE
FAILURE: OPEN
The status of contact are to be set in Service level, CODE 05.