YOKOGAWA FC500G, User Manual, Page: 32 / 41

<6. INSPECTION AND MAINTENANCE>
6-5
IM 12F5A2-01E
6.2 Electrical System
6.2.1 Span Calibration
Perform span calibration at the rate of once every one or two weeks during the initial operation
start period and check the sensitivity changes owing to indicator electrode contamination or the
like to establish a reference for determining the calibration period. After the calibration period
is determined, perform span calibration in an appropriate interval using the above period as a
guide. When the indicator electrode is polished, perform span calibration without fail.
6.2.2 Converter Checking
Check the converter periodically.
The converter check function means to check the converter circuit operation.
Converter checks can be performed using switch operations. Placing the MEAS./CHECK
selector switch in the “CHECK” position transfers the converter input (current input and
temperature input) from connection to the detector to connection to the simulated input. When
the converter is normal, the free available chlorine concentration display indicates 0.90 to 1.10
mg/l regardless of the measuring range. In this case, the analog output is sent out in the range
shown in Table 6.2 corresponding to the measuring range setting.
Table 6.2 Analog Output in Checking
Measuring range Output current Approximate position
0 to 1 mg/l 18.4 to 21.6 mA Approx. 100 % point of full scale
0 to 2 mg/l 11.2 to 12.8 mA Approx. 50 % point of full scale
0 to 3 mg/l 8.8 to 9.9 mA Approx. 33 % point of full scale
6.2.3 Fuse Replacement
For preventive maintenance, it is recommended to replace the power supply fuse once a year.
The fuse rating is 250 V, 1 A.
FUSE
Cap
Power Supply Fuse
Remove the cap by
turning it in the
direction of the arrow.
Figure 6.3 Power Supply Fuse