4.3 Analog Output Unit (FP0R-DA4)
4-9
When data is regarded as an error
• Digital data from the control unit is written in the analog output unit.
When more than the specified amount of data (-2000 to 2000 for voltage type Unit, 0 to 4000
for current type Unit) is written in the Unit, the Unit regards the data as an error and writes
the error flag in WX2. As a result, the D/A conversion is not performed. (For analog output,
the previous data remains unchanged. When the correct data is written, the error flag is
cleared and D/A conversion is executed.)
• Output data and output switching flag are allocated to the same I/O number. Data error can
be detected successfully with the flags when the digital input value is within the range of K-
4096 to K4095. Even when the digital input value is out of the range, however, data
conversion may be mistakenly conducted as shown below. To prevent this problem, be sure
to set up the program to check the upper and lower limits of the digital value.
(Example): When writing K4096 in WY2
K4096= 0001 0000 0000 0000
Analog Output Unit regards Y2D and Y2C as output switching flags:
Y2D, Y2C = 01 <- CH0
Data =0000 0000 0000 <- 0
Consequently, the analog value that is equivalent to the digital value “0” is output from CH0.
Negative data
• When the negative data (minus data) is written, set the output switching flag to two's
complement data. When specifying the minus data in the decimal data, the data
automatically becomes two's complement data. Then, set the output switching flag to two's
complement data in the same way as the plus data.
(Example): When writing -1 in CH0
-1＝1111 1111 1111 1111 <- Two’s complement
Setting the output switching flag: 1101 1111 1111 1111 (Bit C=1, Bit D=0 for CH0)
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