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68
HP E1328A Register-Based Programming
where:
w =
3.65
ym = measured value in step 4
yo =
measured value in step 5
yp =
measured value in step 6
a= (ym) + (w)(yo) + (2
p= w+2
15
c=q=
(2
)(w) + 2
30
32
d= (2
)(w) + 2
Calculate J and K as follows:
32
k = 2
1 −
15
(2
− bo
k
J =
b 1 +
− 2
17
2
where: R= 10.92233 for volts
0.02184467 for current
K should be rounded to a 32 bit unsigned integer. Use the rounded
value of K to compute J. Round J to the nearest integer and express
in 8-bit two's complement form.
NOTE: For maximum speed, precompute the actual output data
using the following equation, and operate the HP E1328A in
uncalibrated mode:
k × x
y = J + x −
32
2
where: x = desired output code (calculated as shown under " Channel
Output Registers" on page 63) and y = value actually sent to the
HP E1328A.
8. Compute a checksum by adding the 6 bytes representing J and K (on
an 8-bit wide basis) and taking the two's complement of the result.
(Checksum is defined to be that number which causes all seven bytes
to sum to zero in byte-wide arithmetic.)
For example (in hex), if offset (J) is 0B 7C and gain (K) is 16 F8 F2
1A (as calculated in step 6), then checksum would be 5F.
9. Use the CALIBRATE command and parameter to load J, K and the
checksum into the D/A Converter's memory.
For example (using hex example values in step 8), entering the
following calculated offset (J), gain (K), and checksum for channel 4
16
- 1)(yp)
16
- 1
17
- 2
+ 1
R
−1)(b
)
1
15
Appendix B
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