Yokogawa GD40 Gas Density Detector - Manual (Page 38)

<2. Installation, Wiring and Piping>
2-15
IM 11T3E1-01E
CAUTION
The following instructions should be observed for the GD402G converter to meet the CE marking
requirements.
1. Connect the supplied surge protector to the power supply.
2. The length of the following cables should be less than 30 m. However, this restriction does
not apply when both detector and converter stay indoors and their cables do not run out-
doors. For details, read Subsection 2.4.1, “Wiring Procedure.”
1) Detector input
2) Pressure transmitter input
3) Analog output1, 2
4) Contact input
Electrical Noise Protection
If a malfunction due to noise occurs, strengthen measures against noise.
For example, ground the detector body or use a double-shielded cable. If a double-shielded ca-
ble is used, ground shields of each conductor at one end. Ground one end of the outer shield on
the detector side to the detector case and connect the other end on the converter side to terminal
13. See the User’s Manual for more instructions on cable installation.
Contact Input Function of the Hydrogen Purity Meter
For hydrogen purity meter, the contact input is used for range selection.
Open: Concentration measurement for Air in CO
2
Close: Concentration measurement for H
2
in CO
2
.
Contact Output Specifications
Indication Specification
MAINT Contact Type: Voltage free, dry contact (mechanical relay contact output)
Contact rating: 250 V AC 3 A or 30 V DC 3 A
Contact arrangement: NO/NC, selectable
ALM
FAIL Contact Type: Voltage free, dry contact (mechanical relay contact output)
Contact rating: 250 V AC 3 A or 30 V DC 3 A
Contact arrangement: NC, fixed
SPAN/FUNC Function contact: Use distinguish between the Hydrogen purity meter and
the Replacement meter.
Select gas contact: Use distinguish measuring ranges in the Replacement meter.
Contact Type: Voltage free, dry contact (mechanical relay contact output)
Contact rating: 250 V AC 3 A or 30 V DC 3 A
Contact arrangement: NO/NC, selectable
ZERO/SEL GAS