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10 FUNCTIONS
10.8 SIL2 A/D Conversion Function
Cycle with which the digital operation value (safety device) is updated
The cycle with which the digital operation value (safety device specified by the SIL2 diagnostic FB library) is updated is
determined by the following formula.
• SIL2 A/D conversion cycle setting N
N is determined by the following rules.
If change of the cycle with which the digital operation value (safety device specified by the SIL2 diagnostic FB
library) is updated needs to be considered, build a system with the cycle calculated with N = 4.
Digital operation value at the time of error detection
If an error is detected with the double input discrepancy detection function or A/D conversion circuit diagnostic function, the
digital operation value of the error-detected channel will be the OFF value (equivalent to 0V/0mA).
When "Scaling enable/disable setting" is "Enable", scale conversion is also applied to the digital operation value of the OFF
value above (equivalent to 0V/0mA).
Relay switching behavior
The SIL2 standard program FB controls the RY40PT5B to switch the connected relay.
• While the double input discrepancy detection function is being executed, the voltage or current from the sensor is input to
the R60AD8-G by switching the relay.
• While the A/D conversion circuit diagnostic function is being executed, the voltage or current from the sensor is cut off by
switching the relay.
A/D conversion enabled channels N
Normal state When the A/D conversion circuit
diagnostic function is executed
Odd number channel only, or even number channel
only
12
Enabled on odd and even number channels 2 4
Input range Digital operation value at the time of error detection
Voltage 0 to 10V 0
0 to 5V 0
1 to 5V -768
1 to 5V (extended mode) -8000
-10 to 10V 0
User range setting (voltage) 0
Current 0 to 20mA 0
4 to 20mA -768
4 to 20mA (extended mode) -8000
User range setting (current) 0
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