CAN-8123/CAN-8223/CAN-8423 user’s manual (Revision 3.00, May/22/2009) ------
176
Note: 1. Because the CAN-8123/CAN-8223/CAN-8423 only supports the hex format, all AI
channels have to transfer to the hex format when storing into this object. The
transformation equation is shown below.
(
)
min
min
max
min
max
min
F
F
F
H
H
H
HexValue
FloatValue
+
−
∗
⎟
⎠
⎞
⎜
⎝
⎛
−
−
=
The Float Value is the result after transformation. The Hex Value is the value which wants
to be transferred. The Hmax and Hmin is the maximum and minimum values of the 2's
complement hex range. The Fmax and Fmin is the maximum and minimum value of the
float range. User can find out the Hmax, Hmin, Fmax, and Fmin in the appendix B. For
example, The input range of the module I-87017 is set to -10V ~ +10V. According to the
table in the appendix B, we can find out the range for hex format is from 0x7FFF (+36767)
to 0x8000 (-32768). Therefore, if the value got from the AI channel of the I-87017 is
4660), the AI value with float format will be calculated as follows.
(
)
(
)
(
)
(
) (
)
V
V
V
V
1.422
10
10
10
32768
32767
32768
4660
≈
−
+
−
−
∗
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
−
−
−
−
By the way, any AI value which is great than the maximum value of the input range will be
automatically set to the maximum value of the input range. And, the AI value which is less
than the minimum value of the input range will be automatically set to the minimum value
of the input range.
Analog Output Devices Entries
Idx Sidx
Description
Type
Attr
Default
6411h
0h largest sub-index supported for
“write analog output 16-bit”
UNSIGNED 8
RO
---
1h
write analog output 1h
UNSIGNED 16
RW
---
...
...
...
...
...
6443
0h largest sub-index supported for
“error mode analog output
16-bit”
UNSIGNED 8
RW
---
1h
error mode analog output 1h
UNSIGNED 16
RW
0
...
...
...
...
---
6444
0h largest sub-index supported for
“error value analog output
UNSIGNED 8
RW
---
