Yokogawa EXA PH202 2-Wire pH/ORP Analyzer - Manual (Page 121)

IM 12B07D02-01E
Appendix 12-9
12-3. PH202G, PH202S 2-Wire pH/ORP Transmitter (Fieldbus Communication)
Quality
Inspection
Standards PH202G, PH202S
2-Wire pH/ORP Transmitter
(Fieldbus Communication)
QIS 12B07D02-61E
1st Edition: Apr. 2007（YK）
1. Scope
This inspection standard applies to the PH202G and PH202S 2-Wire pH/ORP Transmitters
(Fieldbus specification ) .
2. Inspection Items
2.1 Insulation resistance test
* 2.2 Dielectric strength test
2.3 Temperature indication check
2.4 pH indication check
* 2.5 ORP indication check
* 2.6 Fieldbus communication functional check
Note: Items marked with an asterisk (*) may only be confirmed by a test certificate.
3. Inspection Methods, Standards and Conditions
z
Connect the testing circuit as shown in Figure 1. Allow the instrument to warm up for at least
5 minutes before conducting the tests. For the connections for the insulation resistance test,
follow the instructions in Section 3.1 and for the connections for the dielectric strength test,
follow the instructions in Section 3.2.
z
Use test equipment shown in Figure 1, or equivalent, for the tests.
3.1 Insulation Resistance Test
(1) Apply 500 V DC between the power supply terminals shorted together (+ and –) and the
earth terminal (G). The insulation resistance must be 100 MΩ or greater.
(2) Apply 500 V DC between the input terminals shorted together (11 to 17) and the earth
terminal (G). The insulation resistance must be 100 MΩ or greater.
3.2 Dielectric Strength Test (Required Only for PH202S)
Apply 600 V AC, an AC voltage of substantially sinusoidal waveform with a frequency of 50 Hz
or 60 Hz, between the terminals shown below, for at least 2 seconds. The insulation must
withstand this voltage. (The sensed current should be 10 mA.)
(1) Between the power supply terminals shorted together (+ and –) and the earth terminal (G)
(2) Between the input terminals shorted together (11 to 17) and the earth terminal (G)
(3) Between the input terminals shorted together (11 to 17) and the power supply terminals
shorted together (+ and –)
3.3 Temperature Indication Check
Connect the instruments as shown in Figure 1, and set them as follows.
Connect a shorting bar between terminals LOW and IMP.
Decade resistance box: 921.6 Ω
Standard voltage source: 0 mV
DC source: 24 V DC
change the resistance value of the decade resistance box as shown in Table 1. The
corresponding temperature indication must be within the range.