KEYENCE Visual KV Series - Manual (Page 375)

9.4 Programming KV-10/80 Series Only
KV
-300
KV-10/80
Chapter 9 KV-AD4/DA4 Analog I/O Unit
1-351
1
9
About Digital Data after A/D Conversion
Data Memory to which digital data is written
The KV-AD4 converts analog signals that have been input from external instruments
to digital data, and writes this digital data to data memory for A/D conversion on the
CPU.
Data memory for A/D conversion on the CPU is used only when the KV-AD4 is
connected to the CPU. This memory can be used as regular data memory when the
KV-AD4 is not connected to the CPU. When the KV-AD4 is connected to the CPU,
this memory can be used only for A/D conversion and not for other applications.
Note: When the KV-AD4 is connected to the CPU, the conversion data is written at
each scan even if the channels on the KV-AD4 are not in use.
The address of the data memory to which digital data is written varies according to
the channel (terminal) to which the instrument for analog input is connected. The
following table shows the correspondence between channel and data memory.
Channel Data Memory
CH0
CH1
CH2
CH3
DM0992
DM0993
DM0994
DM0995
Digital data content
The numerical values of the digital data that is written to data memory for A/D
conversion are not obtained by simply converting actual voltage or current to binary
format. During conversion they are influenced by the input characteristics preset by
the user. The KV-AD4 voltage and input characteristics are as follows.
For example, when analog input is +5 V, 3000 will be written to the data memory
for A/D conversion. If the analog input is outside of the input range, 0 and 4095 are
written as the minimum and maximum values.
Digital data
+4000
+3000
+2000
+1000
-10 +10 -8 -6 -4 -2 0 +2 +4 +6 +8
Voltage
(V)
Range: ±10 V
Voltage input characteristics
Digital data
+4000
+3000
+2000
+1000
0 2 4 6 8 10 12 14 16 18 20
Range: 4 to 20 mA
Current
(mA)
Current input characteristics
KVHKA Chap 09.p65 08.3.11, 11:20 AM 351