Double Input Discrepancy Detection Function - Mitsubishi Electric R60AD8-G User Manual

Double input discrepancy detection function

This function detects an error by mutually referencing digital operation values of two R60AD8-G modules.
The verification result is sent to the SIL2 diagnostic FB library.
• If the verification result is abnormal, the SIL2 diagnostic FB library counts the number of errors that continuously occur from
the first error, and generates a double input discrepancy detection error (error code: 1EDH) when the number of errors
reaches a specified value.
• If the verification result is normal, the mean value from the A/D conversion by the R60AD8-G (Main) and R60AD8-G (Sub)
is stored as a digital operation value in the safety device specified by the SIL2 diagnostic FB library, and the number of
errors counted by the SIL2 diagnostic FB library is cleared at this point.
This function uses the SIL2 safety program FB (M+SIL2ADG_ADConv_R) to operate.
Setting procedure
To use the double input discrepancy detection function, the following parameter settings and a program by the SIL2 diagnostic
FB library are required.
• "Duplex input error range setting"
• "Duplicated input mismatch detection count"
• "Duplicated input mismatch automatic recovery setting"
• "Duplicated input mismatch automatic return count"
■"Duplex input error range setting"
For the R60AD8-G (Main) and R60AD8-G (Sub), set for each channel the allowable error range for verifying digital operation
values obtained from each module.
[Navigation window]  [Parameter]  [Module Information]  [R60AD8-G(S2M)]  [Module Parameter]  [Application
setting]  [Duplex input error range setting]
Item
Duplex input error range setting
Note that the allowable digit value varies depending on the "Scaling enable/disable setting" and range setting.
"Scaling enable/disable Range setting
setting"

"Disable"
"Enable" 0 to 10V, 0 to 5V, 1 to 5V, 0 to
20mA, 4 to 20mA, 1 to 5V
(extended mode), 4 to 20mA
(extended mode)
-10 to 10V, user range setting
(voltage), user range setting
(current)
• Adjust this setting if a double input discrepancy detection error (error code: 1EDH) occurs frequently due
to a noise affecting the digital operation value in noisy electrical environment.
• The setting of "Duplex input error range setting" is also applied to the error range of A/D conversion circuit
diagnostics. ( Page 286 A/D conversion circuit diagnostic function)
Setting range
0.5 to 5.0%
Allowable digit value
Maximum digital output value  "Duplex input error range setting"
Example) When "Duplex input error range setting" = 1.0%, the value is as follows.
32000  0.010 = 320 digit
|("Scaling upper limit value" - "Scaling lower limit value")|  "Duplex input error range setting"
Example) When "Scaling upper limit value" = 8000, "Scaling lower limit value" = -4000,
"Duplex input error range setting" = 1.0%, the value is as follows.
|(8000 - (-4000))|  0.010 = 120 digit
(|("Scaling upper limit value" - "Scaling lower limit value")|  "Duplex input error range setting")
 2
Example) When "Scaling upper limit value" = 8000, "Scaling lower limit value" = -4000,
"Duplex input error range setting" = 1.0%, the value is as follows.
(|(8000 - (-4000))|  0.010)  2 = 60 digit
10 FUNCTIONS
10.8 SIL2 A/D Conversion Function
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