Yokogawa 2-Wire Dual Channel Transmitter/Analyzer FLXA21 - Manual (Page 66)

<4. COMMISSIONING OF pH/ORP>
4-12
IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
Table 4.2 Error configuration
Display item Description Default
pH too high The pH value exceeds 16.00. Warn.
pH too low The pH value is lower than –2.00. Warn.
Temperature too high Measured process temperature is higher than the
maximum limit.
Warn.
Temperature too low Measured process temperature is lower than the
minimum limit.
Warn.
ORP too high The ORP value is higher than 1500 mV. Off
ORP too low The ORP value is lower than –1500 mV. Off
rH too high The rH value is higher than 100. Off
rH too low The rH value is lower than 0. Off
Matrix config. error The temperature compensation matrix is not set
properly (see Section 4.2.3).
Fault
Calib. time exceeded Calibration time exceeds the calibration interval
(see Section 4.2.4).
Off
Wash half-time error The response to wash is abnormal. Off
Impedance 1 too high The sensor must be checked. Off
Impedance 1 too low
Impedance 2 too high
Impedance 2 too low
CAUTION
If canceling an error configuration could be risky, do not cancel it as a dangerous situation may
result.
NOTE
The “Impedance 1 too high/too low” and “Impedance 2 too high/too low” error items are displayed
in the Error configuration screen. In general, for a pH sensor, “Impedance 1” means “glass
electrode,” and for an ORP sensor, it means “metal electrode.” “Impedance 2” represents the
reference electrode in all cases. The “Impedance 1 too high/too low” and “Impedance 2 too high/
too low” errors are applied to sensors with a liquid earth. Sensors with a liquid earth include
PH8EFP, PH8ERP, PH8EHP, OR8ERG, OR8EFG, etc. For sensors not equipped with a liquid
earth, these errors should all be set to Off; these sensors include HA405, HA406, DPA406,
DPA405, DPAS405, HF405, HA485, DPA485, etc. Moreover, for measuring a solution with low
conductivity such as when using a pH meter for pure water, set the “Impedance 2 too high” error
to Off. Otherwise, no impedance can be detected.
NOTE
When ORP is specified as a sensor type in “Sensor setup”, and when an ORP sensor, such as
OR8ERG and OR8EFG, doesn’t have any temperature element, set both of “Temperature too
high/low” in “Error ” to Off so that no related error is caused. Due to the open input of temperature
signal, a false error may happen as if temperature goes over a high limit or a low limit.