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Analog Input Units Section 5-4
Off-wire Detection When a disconnection occurs in an analog input line (voltage input or current
input), the Off-wire Detection Flag turns ON for each input that is enabled in
the number of AD conversion points. The Off-wire Detection Flags are
included in the Analog Status Flags.
When Off-wire Detection is enabled, the value of AD conversion data is set to
7FFF hex. When the input returns to a value within the range that can be con-
verted, the Off-wire Detection function will automatically be turned OFF, and
normal data conversion will occur.
Off-wire Detection functions with input ranges of 1 to 5 V or 4 to 20 mA only.
With the 1 to 5 V input range, an off-wire condition is detected when the input
voltage is below 0.76 V (less than 6%). With the 4 to 20 mA input range, an
off-wire condition is detected when the input current is below 3.04 mA.
User Adjustment Depending on factors such as the characteristics and connection methods of
the input device, the input can be adjusted to compensate for error in the input
voltage or current. The following diagram shows when compensation is
applied to the conversion line at the two points for 0% and 100%.
The following table shows the input ranges that support user adjustment.
Setting Procedure (Example: DeviceNet Configurator)
1,2,3... 1. In the Network Configuration Window for the Slice I/O Terminal, double-
click the icon of the Slice I/O Terminal that is to be set. Alternatively, right-
click the icon and select Parameters - Edit. The Edit Device Parameters
Window will be displayed.
2. Click the I/O Module Tab.
3. Click the Edit Button on the I/O Module Tab Page. The Edit Unit Parame-
ters Window will be displayed.
Input range Low Limit High Limit
0 to 5 V –0.25 to 0.25 V 4.75 to 5.25 V
1 to 5 V 0.8 to 1.2 V 4.8 to 5.2 V
0 to 10 V –0.5 to 0.5 V 9.5 to 10.5 V
–10 to 10 V –11 to –9.0 V 9.0 to 11 V
4 to 20 mA 3.2 to 4.8 mA 19.2 to 20.8 mA
0 to 20 mA –1.0 to 1.0 mA 19 to 21 mA
100%
0%
Conversion data
After adjustment
Before adjustment
Voltage/current
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