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Understanding the Features
3--11
When placing a BCD double number in
the display registers, the first register
numerically in the sequence of two
registers (M+4, M+6, M+8 or M+10) will
contain the four least significant digits of
the number. The second register in the
sequence (M+5, M+7, M+9 or M+11)
contains the data for the four most
significant digits of the BCD double
number.
For example, to display the number
92345678 on the top line of the display,
the top line data registers, M+4 and M+5,
must
contain
5678
and
9234
respectively.
Example: BCD Double
92345678
9234 must be in register M+5
5678 must be in register M+4.
The OP--440 has the capability to display Floating Point (or Real) numbers if you
select the option
Float
when the display message is being defined in the
OP--WINEDIT software.
Floating point numbers can only be used with the D2--250, D3--350, and D4--450
CPUs since they are the only compatible CPUs that support the IEEE 32-bit floating
point number format, which is where the floating point numbers are stored. They
always occupy two 16-bit register locations regardless of the size of the number. See
the PLC User Manual for more information on the IEEE 32-bit floating point number
format.
An IEEE 32-bit floating point number has a range of --3.38 to
+3.38. The OP--440 will be able to display any number within that range.
The panel always uses the format
¦
X.XXE
¦
XX to display the numbers.
The panel does not have the ability to display all the significant digits of a floating
point number, it only displays the first three significant digits. The OP--440 truncates
the remaining digits so you always see the true number. The two examples below
show the data contained in the PLC registers and the corresponding value displayed
on the panel in its format. Notice how the data is truncated.
The configuration of a floating point
number message is similar to any other
message. First, you select the message
number, then you type in the text using
nine caret symbols (^) as a place holder
for each of the nine floating point number
symbols. Next, select the
Float
option for
the data format.
Example: Floating Point Numbers
12301.789
PLC Registers
OP--440 Display
123.96783
+123E+04
+123E+02
Let’s say you wanted to configure message #58 to display a floating point number.
In the OP--WINEDIT software, select OP--440 as the module type, and then select
message #58 with the mouse. Type in the following message: “Float Pt ^^^^^^^^^”
and select floating point as the message format.
To display a number , simply move it into the desired display line data registers and
load the appropriate message number into the corresponding line message
selection register. For example, if you display the number 632.15 in message #58,
it will be displayed as “Float Pt # +632E+02”.
Displaying Floating
Point Numbers
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