ROHRBACK COSASCO SYSTEMS CORRATER 9020, Руководство пользователя

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11
Chapter 4
Operation
After the initial measurement cycle is completed, the transmitter will update the loop current
at the completion of each measurement cycle. If logging this data, it is not necessary to
sample the loop current more often than once each measurement cycle.
To convert the 4-20 mA. signal into CORROSION RATE in mils per year (MPY), the
conversion formula is as follows:
CORROSION RATE (MPY) = {(I
L
- 4)/16} X CORROSION RANGE (selected)
To convert the 4-20 mA. Signal into IMBALANCE UNITS, the conversion formula is as
follows:
IMBALANCE (2.5
µ
A./unit) = {(I
L
- 4)/16} X IMBALANCE RANGE (selected)
The constant of 2.5
µ
A. per IMBALANCE UNIT is equivalent to a current density of 0.5
µ
A.
per square centimeter of electrode area and has been determined empirically so that the
magnitude of the imbalance measurement can be compared with the corrosion rate in mils
per year. For a more detailed description of the imbalance measurement function, please
refer to Appendix B.