AEZ 801 / 802
Timing of measurements
General
Normal cycle
The timing of measurements depends on the cycle used, defined at configuration
(See
Modification of the Scanning Cycle, p. 242): normal cycle or fast cycle.
The input scanning cycle is fixed and has a value of 32 ms, independent of the number of inputs used.
Example of a scanning cycle using only channels 0, 1, 6, and 7:
Fast cycle
Channel 0
4 ms
Channel 1 Channel 6
4 ms
Scaning cycle = 32 ms
4 ms
Channel 7
4 ms
Only the channels used are scanned, even if they are not consecutive. This helps to improve the channel scanning cycle time.
The cycle time for scanning the channels is given by the formula:
Cycle time (ms) = 4 ms x N
N = number of channels used
For example, if 4 channels are used, the scanning cycle time will be:
4 x 4 = 16 ms
Illustration:
Channel 1 Channel 3 Channel 5 Channel 7
4 ms 4 ms 4 ms
Scanning cycle = 4 x 4 = 16 ms
4 ms
Note: In fast cycle, the user can assign the channels to FAST task (See
Modification of the Task Assigned to the Module Inputs, p. 243). In this case, it is
recommended that you do not assign too many analog input modules to the FAST task,
TLX DS 37 PL7 xxE
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