Cooper Instruments & Systems DFI INFINITY Digital Force Indicator/Controller - Manual (Page 42)

SC=(O2-O1)/(I2-I1)
This value is entered/read with these “08”, 0B” and “17” command suffixes, and also used in calculating the
corresponding Offsets (see Section 10.9).
NOTE: True value for output scale factor is stored in its location in EEPROM. When the program is running, it
combines this value with calibration scale of analog out board and stores new value in output scale’s RAM
location (CALLED MODIFIED OUTPUT). Therefore, “P17” for this scale factor should be used very carefully
(avoid using if possible). But with “G17”, the value of modified output scale factor can be read.
The most significant nibble of the scale factor data sets the decimal point (power of 10 multiplier) for the least-
significant nineteen bits, which give the magnitude using a right-hand decimal point (decimal 499,999 full scale).
The bit in between, #19, is the sign bit, “0” for “+” and “1” for “-“, which is OR’d with the magnitude to get the
HEX value of the second nibble. The decimal-point code is given in Table 10.9. The figure “4” indicates the
maximum value in that position and “x” is any chosen decimal digit.
Bit pattern information is as follows:
1) Bits 0 to 18 belong to the absolute value.
2) Bits 20, 21, 22, 23 belong to the decimal point as shown in Table 10.9.
3) Bit number 19 belongs to the sign and is “0” for positive and “1” for negative.
Table 10.9 Reading Scale (“RD SC”), Input Scale (“IN SC”), and Output Scale (“OUT SC”) Bits 23, 22, 21
and 20
BIT NUMBER
23 22 21 20 DECIMAL NUMBER POWER OF 10
MULTIPLIER
0 0 0 0 4xxxxx0. 1
0 0 0 1 4xxxxx.0 0
1 0 1 0 4xxxx.x0 -1
0 0 1 1 4xxx.xx0 -2
0 1 0 0 4xx.xxx0 -3
0 1 0 1 4x.xxxx0 -4
0 1 1 0 4.xxxxx0 -5
0 1 1 1 .4xxxxx0 -6
1 0 0 0 .04xxxxx0 -7
1 0 0 1 .004xxxxx0 -8
1 0 1 0 .0004xxxxx0 -9
1 0 1 1 .00004xxxxx0 -10
1 1 0 0 .000004xxxxx0 -11
1 1 0 1 .0000004xxxxx0 -12
1 1 1 0 .00000004xxxxx0 -13
1 1 1 1 .000000004xxxxx0 -14
EXAMPLE: Desired reading scale factor is 123.45. The magnitude is 12345, which is the hex 03039. The
polarity is negative, so the 19
th bit is a “1”, giving hex “80000”; when OR’2 with the magnitude, the least-
significant 5 nibbles are hex “83039”.
The decimal point is two places to the left of the right-hand position (e.g., of the 6-digit display). The decimal
point is thus –2, which is MSB of 3 from the Table 10-9.
OR’d with the other 5 nibbles, hex “383039”, write this factor to the EEPROM of meter hex #15 with:
*15W08383039. The meter will echo 15W08 if you have set “BUS.3=1”.
10.5 Reading Offset (“RDG OF”), Input Offset (“INP OF”), or Output Offset (“OUT OF”)
These 3 (“09”, “25” and “26” command suffixes) all use the same 3-byte (6-nibble or 6 character) format. The
most significant bit is the sign bit, “=0” for a positive value, “=1” for a negative value. The other 3 bits of the
CF 125 INFINITY SC GUIDE 38 M1519/N/0605