Vaisala MMT330 - Manual (Page 142)

User's Guide _______________________________________________________________________
140 __________________________________________________________________ M210733EN-G
Conversion Model with Oil-specific Coefficients
For additional accuracy, oil-specific conversion model can be used both
for mineral and silicon based oils. An oil sample has to be sent to Vaisala
for modelling. As a result, the specific coefficients (A and B, see formula
1) for the transformer oil are determined by Vaisala. For additional
information, please contact Vaisala.
The determined coefficients of the transformer oil can be programmed to
the MMT330 by Vaisala or by a user according to the instructions
presented in this chapter.
NOTE Conversion Model With Oil-specific Coefficients is always needed for
silicone based oils.
Setting Oil Coefficients Using Serial Line
If the ppm conversion and oil-specific coefficients have been
programmed at Vaisala, the user does not have to set the conversion co-
efficients.
If a user has defined the coefficients or separately received from Vaisala
the oil-specific coefficients A and B, related to his own oil type, the
coefficients can be set to the software of MMT330 by using a serial bus
or through an RS 485/422 serial module or through keypad/display.
OIL
Use the serial line command OIL to set oil-specific parameters for ppm
conversion.
Example:
>oil
Oil[0] : -1662.6999 ?
Oil[1] : 7.3694 ?
>
where
Oil [0] corresponds to parameter A
Oil [1] corresponds to parameter B