6 Commissioning Promag 53 PROFIBUS-DP/-PA
104 Endress+Hauser
6.4.3 Cycle times
Measurement value processing and data communication is effected by Promag in three
steps:
1st step: Processing measurement values
This involves the calculation of the primary measured variable “volume flow” on the
basis of sensor signals.
The duration of the sampling intervals will depend on the type of sensor that is being
used, the nominal diameter and the energy supply (50 Hz, 60 Hz, DC). The typical
processing times of Promag 53 can be found in the following table:
2nd step: AI block calculation
The default values of the AI block and the totalizers are calculated on the basis of the
measured variable ascertained while processing the measurement values (volume flow
and calculated mass flow) and are then copied to a cyclic data telegram.
The AI block calculation is effected within a period of max. 50 ms per block.
Note:
Each measurement only involves the calculation of the AI blocks or totalizer blocks. This
AI block or totalizer block will only be calculated if it has been activated using the con-
figuration software (see Page 97). The deactivation of parameters which are not
required in the cyclic data telegram will improve the real time performance of the
flowmeter.
Sensor DN Scan interval in [ms]
[mm] 50 Hz 60 Hz DC
Promag W
Promag P
15...50
65
80...100
125...200
250...400
450...500
600
700...750
800...900
1000...1050
1200
1350...1400
1500
1600...1700
1800
2000
60.0
60.0
60.0
100.0
120.0
140.0
160.0
200.0
240.0
300.0
300.0
340.0
380.0
420.0
480.0
500.0
50.0
50.0
66.7
100.0
116.7
150.0
166.7
200.0
250.0
300.0
300.0
350.0
400.0
450.0
500.0
500.0
55.0
72.5
72.5
109.0
126.6
145.0
164.0
200.0
217.0
256.0
294.0
323.0
370.0
400.0
435.0
435.0
Promag H 2...25
40...65
80...100
40.0
60.0
60.0
33.3
50.0
66.7
-
36.0
36.0
AI-Block-
berechnung
..........
.......
First
block
Data telegram
Second
block
Mass flow
Volume flow
Sensor
signals
1. Step
2. Step 3. Step
PROFIBUS
Protocol chip
Inquiry from
Master
AI block
calculation
Totalizer block
calculation
Volume flow
Signal processing
Mass flow
F06-x3PBxxxx-02-xx-xx-en-000
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