Mitsubishi Electric R60AD8-G User Manual page 281

Timing chart of the SIL2 A/D conversion function
The function behavior differs between the normal state and when the A/D conversion circuit diagnostic function is executed.
■Normal state
Odd number channel double input discrepancy detection and even number channel double input discrepancy detection are
repeated alternately for each SIL2 A/D conversion cycle.
1st cycle
SIL2 A/D conversion
cycle
Double input
discrepancy
detection
(odd CH) (1)
Digital operation
value for odd channel
Digital operation
value for even channel
■When the A/D conversion circuit diagnostic function is executed
When the A/D conversion circuit diagnostic function is executed, the double input discrepancy detection function and A/D
conversion circuit diagnostic function are repeated alternately for each A/D conversion circuit diagnostic cycle. (The double
input discrepancy detection function is not executed for start-up A/D conversion circuit diagnostics.)
A/D conversion circuit diagnostics consists of two patterns of digital values for diagnostics, and up to six retries are attempted
for each pattern. Each digital value for diagnostics consists of four cycles.
Therefore, the A/D conversion circuit diagnostic function will be executed for 8 (minimum) to 56 (maximum) cycles.
The following figure shows the entire timing chart of the A/D conversion circuit diagnostics.
Digital value for diagnostics (pattern 1)
A/D conversion circuit A/D conversion circuit
diagnostics: Digital diagnostics: Digital
value for diagnostics value for diagnostics
(pattern 1), 1st time (pattern 1), 2nd time
Retries of 6 times at maximum
The following figure shows the timing chart of one digital value for diagnostics.
1st cycle
SIL2 A/D conversion
cycle
Double input
discrepancy
detection
(odd CH) (1)
Digital operation
value for odd channel
Digital operation
value for even channel
2nd cycle
SIL2 A/D conversion SIL2 A/D conversion SIL2 A/D conversion
cycle cycle cycle
Double input Double input Double input
discrepancy discrepancy discrepancy
detection detection detection
(even CH) (2) (odd CH) (3) (even CH) (4)
Value of (1)
Value of (2)
A/D conversion circuit A/D conversion circuit
diagnostics: Digital diagnostics: Digital
value for diagnostics value for diagnostics
(pattern 1), 7th time (pattern 2), 1st time
2nd cycle
SIL2 A/D conversion SIL2 A/D conversion SIL2 A/D conversion
cycle cycle cycle
A/D conversion Double input A/D conversion
circuit diagnostics discrepancy circuit diagnostics
(odd CH of the detection (even CH of the
R60AD8-G (Main)) (even CH) (2) R60AD8-G (Main))
Value of (1)
3rd cycle
SIL2 A/D conversion SIL2 A/D conversion
cycle cycle
Double input Double input
discrepancy discrepancy
detection detection
(odd CH) (5) (even CH) (6)
Value of (3)
Value of (4)
Digital value for diagnostics (pattern 2)
A/D conversion circuit
diagnostics: Digital
value for diagnostics
(pattern 2), 2nd time
Retries of 6 times at maximum
One digital value for diagnostics
3rd cycle
SIL2 A/D conversion SIL2 A/D conversion
cycle cycle
Double input A/D conversion
discrepancy circuit diagnostics
detection (odd CH of the
(odd CH) (3) R60AD8-G (Sub))
Value of (2)
4th cycle
SIL2 A/D conversion SIL2 A/D conversion
cycle cycle
Double input Double input
discrepancy discrepancy
detection detection
(odd CH) (7) (even CH) (8)
Value of (5) Value of (7)
Value of (6)
A/D conversion circuit
diagnostics: Digital
value for diagnostics
(pattern 2), 7th time
4th cycle
SIL2 A/D conversion SIL2 A/D conversion
cycle cycle
Double input A/D conversion
discrepancy circuit diagnostics
detection (even CH of the
(even CH) (4) R60AD8-G (Sub))
Value of (3)
Value of (4)
10 FUNCTIONS
10.8 SIL2 A/D Conversion Function
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