ICP DAS USA CAN-8823, User Manual

Page: 179 / 198

CAN-8x23 user’s manual (Revision 3.20, Ma r/08/2012) ------ 179
Note: 1. Because the CAN-8x23 only supports the hex format, all AI channels have to transfer to
the hex format when storing into this object. The trans formation equation is shown below.
 
min min max
min max
min
F F F
H H
H HexValue
FloatValue
  









The Float Value is the result aft er 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. Us er 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 t he A I channel of the I-87017 is
4660), the A I 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 aut omatically set to the minimum value
of the input range.
Analog Output Devices Entries
Idx Sidx Description Ty pe Attr Default
6411h 0h largest sub-index supported for
“write analog output 16-bit”
UNS IGNED 8 RO ---
1h write analog out put 1h UNS IGNED 16 RW ---
... ... ... ... ...
6443 0h largest sub-index supported for
“error mode analog output
16-
bit”
UNS IGNED 8 RW ---
1h error mode analog output 1h UNS IGNED 16 RW 0
... ... ... ... ---
6444 0h largest sub-index supported for
“error value analog output
16-
bit”
UNS IGNED 8 RW ---