18 Rockwell Automation Publication ICSTT-RM448M-EN-P - February 2021
Chapter 2 The AADvance Safety Controller
The scan time is:
Scan time = 39.3 ms (minimum cycle time overhead)
+ Sync time
+ Total number of modules * 0.04 ms
+ (Number of module groups x scan time shown above)
Where:
Sync time is a function of the total number of modules defined according
to the following table:
Though the average scan time will be within 1 ms of the scan time calculated
above the calculation does not take into account the effects of application logic
and network communication, and individual scans can vary by up to +/- 4 ms
around the average scan time.
Throughput time is the time from input change to output action. For
asynchronous inputs the throughput times can be derived from the Scan time
calculated above according to the following formula:
• Minimum throughput time = Scan period + 7 ms
• Maximum throughput time = 2 x Scan time + 13 ms
EXAMPLE: An example configuration scan time:
System configuration includes T9432 Analogue input simplex modules x 30
and T9451 Digital output simplex modules x 18.
Table 2 - Typical Module Scan Times
Module Scan
T9402
Digital input module, 24 Vdc, 16 channel
Simplex
Dual
Triple
0.924 ms
1.676 ms
2.453 ms
T9432
Analogue input module 24 Vdc, 16 channel
Simplex
Dual
Triple
1.170 ms
1.965 ms
2.656 ms
T9451
Digital output module, 24 Vdc, 8 channel
Simplex
Dual
1.174 ms
2.202 ms
T9482
Analogue output module, 24 Vdc, 8 channel
Simplex
Dual
0.981 ms
1.761 ms
Minimum cycle time overhead 39.3 ms
Scan overhead for each module 0.04 ms
0..10 modules 20 ms
11..20 modules 22 ms
21..30 modules 24 ms
31..40 modules 27 ms
41..48 modules 32 ms.
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