Yokogawa Touch Screen GP20 - Manual (Page 355)

5-1
IM 04L51B01-01EN
Maintenance and T
roubleshooting
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5.1 Maintenance
5.1.1 Periodic Inspection
Check the operation periodically to keep the GX/GP in good working order.
Perform the following inspections, and replace worn parts as needed.
• Is the display and storage functioning properly?
If not, see section 5.2, “Troubleshooting.”
• Has the brightness of the LCD backlight deteriorated?
If replacement is necessary, see section 5.1.5, “Recommended Replacement Periods for
Worn Parts.”
5.1.2 Calibrating AI Modules
To maintain measurement accuracy, we recommend that you calibrate AI modules once a
year.
YOKOGAWA dealers can provide calibration servicing.
For details, contact your nearest YOKOGAWA dealer.
Required Instruments
To calibrate the AI modules, you need calibration instruments with the following accuracy
and resolution.
Recommended Instruments
• DC voltage standard : DC Voltage/Current Standard
Must meet the following specifications (M/9100 by FLUKE or
equivalent)
Output range: 20 mV to 100 V
Output accuracy of output range: ±(0.01%+1 μV) or better
• Resistance standard: Must meet the following specifications (ADR3204 by Alpha
Electronics or equivalent)
Resistance setting range (resolution):
0.2 to 1999 Ω (0.001 Ω), 0.2 to 19999 Ω (0.01 Ω)
Resistance accuracy of the resistance setting range:
± (0.01% of + 2 mΩ ) or better
• 0°C standard temperature device : ZC-114/ZA-10 by Coper Electronics or equivalent
Main specifications
Standard temperature stability accuracy: ±0.05°C
For information on purchasing these calibration instruments, contact your nearest YOKOGAWA dealer.
Calibration Procedure
1
Wire the GX/GP and the calibration instruments as shown in the following figure, and
adequately warm up the instruments (the warm-up time of the GX/GP is at least 30
minutes).
2
Check that the operating environment such as ambient temperature and humidity is
within the standard operating conditions (see “General Specifications”).
3
Apply appropriate input signals corresponding to 0, 50, and 100% of the input range
and calculate the errors from the readings. If the error does not fall within the accuracy
range of the specifications, servicing is required. Contact your nearest YOKOGAWA
dealer.
You can also perform the A/D calibration and adjust the GX/GP within the accuracy
specifications. Follow the instructions in section 5.1.3, “Performing A/D Calibration and
Adjusting the Input Accuracy.”
Note
For thermocouple inputs, you must measure the temperature of the input terminal and apply a
voltage taking into account the reference junction temperature.
Chapter 5 Maintenance and Troubleshooting