20
Programming Notes:
If the Degrees Per Tap value is not known, the 1250B can be used to determine this
value. Follow these steps to determine the Degrees Per Tap value:
1) Program the 1250B for Linear Scaled Mode as follows:
OP 2 Operating mode = 1 OP 3 Counts Per Turn = 360
OP 4 Left Digits = 3
2) Return to the “run” mode. The 1250B should read a number with 1 decimal place.
3)
Create a table with three columns, Tap Number, Degrees, and Difference, on a piece of
paper.
4)
Move the LTC to as many taps as possible. Record each tap number and the
corresponding degree reading displayed on the 1250B in the table.
5) Subtract one degree reading from the next, for each tap, and write it in the Difference
column in the table.
6) The differences should all be approximately the same. Take an average of the numbers in
the Difference column. The result is the Degrees Per Tap number that the 1250B needs
for the OP 21,
D SEG, or DEGSEG
command.
7) If there are differences that appear to be two, three or more times the normal difference
between taps, these are “Double Taps” or “Multiple Taps”. Do not average these numbers
with the rest when calculating the degrees per tap. If they occur at only one position, such
as Neutral, then use the OP 22, NEu, NEUTRALS command to program the 1250B for
more than one neutral.
8) If the multiple taps occur at more than one position, the Non-Linear mode must be used.
Use the
OP 60, Add, TADD
or
OP 64, LEArn, TLEARN
commands to add the degree
reading and tap number to the Non-Linear Conversion Table, as described on page 15.
A
data point pair must be entered for EVERY tap.
Programming for the Analog Output option is covered in Section 3.1.
Programming for the High/Low Relays option is covered in Section 3.2.
Programming for the Serial RS-232 Communication option is covered in Section 3.3.
Programming for the Serial RS-485 Communication option is covered in Section 3.4.