Section 5 | Operation
Page | 16
©
2021
– Valeport Ltd
5.9.3.1 Straight Line Fits.
In a terminal emulation program (for example TERMINAL in Windows), set the communications to
4800 baud, 8 data bits, 1 stop bit, 0 parity bits. Also, check that the correct comms port on the PC
is being used. If necessary, check that the Local Echo is On, or you will not be able to see what
you are typing appear on the screen.
With the 0012B CDU connected to the PC via the interface lead provided, select USER CAL from
the OPTIONS MENU and then SET USER CAL. Check the PC connection.
In the terminal emulation program, the message 'Enter Calibration Data' appears.
The calibration data should then be entered as follows:-
#CODE Ident_number Coefficient1 Offset1 Max_lt1 Coefficient2 Offset2 Max_lt2 Coefficient3
Offset3 Max_lt3 Coefficient4 Offset4 Max_lt4<cr>
where
#CODE
=
the set calibration function code (from Section:
Ident_number
=
Calibration Function No. For a line fit, this will be 1. (See Table 1
above).
Coefficient
=
slope of the line.
Offset
=
the line constant
Max_lt
=
the end point beyond which the present straight line parameters no
longer operate
All straight line fits are considered to be four line fits, and therefore sufficient coefficients must
always be entered to ensure correct calculation of the calibration factor. For line fits less than four
line fits the unused parameters should be filled in with zeros.
For example, the calibration for the BFM001 is a two straight line fit, with equations:
V = 0.013 + 0.2512n (up to 0.32 revs/sec)
V = 0.008 + 0.2667n (from 0.32 up to 11.28 revs/sec)
where V is velocity in m/s and n is revolutions per second.
To enter this calibration in OTHER3, the following would be typed. Note the space after each
number:
#003 1 0.2512 0.013 0.32 0.2667 0.008 11.28 0 0 0 0 0 0
To change the name of the meter, type the correct #CODE followed by the new name (upper and
lower cases are recognised). For example, to change the name from OTHER3 to BFM001, enter:
#013 BFM001
When all required data has been input, enter #000, and the 0012B will automatically return to the
Options Menu.