Process historian function block execution – Rockwell Automation T3832 ICS Regent Historian Package for Winterpret User Manual
Page 41

Historian Package for
W
INTERPRET
(T3832)
P D - 6 0 4 2 M a r c h , 0 6
41
3. The sequence of events event buffer is being uploaded to
the PC running W
INTERPRET
.
Using a sequence of events function block containing 100
entries, the scan times shown in Table 3 were observed.
Table 3. Sequence of Events: Characteristic Scan Times.
MODE
SCAN TIME (msec)
Running but no events recorded
Negligible
100 events per scan recorded
1
2000 word buffer uploaded
1
Process Historian Function Block Execution
The Regent executes a process historian function block using
the sequence described below.
Start Contact Is On
If the start contact is on and the clear contact is off, the
following occurs:
1. The process historian time accumulate is incremented.
2. If the time accumulate has reached or exceeded the sample
time, the current time stamp and state of all variable
entries are recorded in the process historian buffer and the
time accumulate is reset.
3. If the time accumulate has not reached the sample time,
no recording occurs on this scan.
Clear Contact Is On
If the Clear Contact is on (regardless of the state of the start
contact and time accumulate), the following occurs:
1. The process historian buffer is cleared (by resetting
internal buffer pointers).
2. The time accumulate is reset to zero.
3. No variable entries are recorded this scan.
Execution Speed
The execution speed of a process historian function block can
be measured in three modes: