Primes PROFINET - Minimum and Maximum Energy Input Per Measurement

PowerMeasuringModule PMM
35,0(6
39
Revision 13 EN - 02/2023
8.3 Minimum and maximum energy input per measurement
The measured temperature rise in the absorber is decisive for an accurate and reproducible measurement.
Regardless of the starting temperature, an energy input of approximately 400J to 1000J per measurement
is recommended.
Example: At 1kW laser power the recommended pulse length is 400ms.
E = P·t = 1000W · 0.4s = 400J
Fig. 8.5 on page39 shows the permissible energy input for a measurement as a function of the absorber
temperature.
25 35 45 55 65 75
Absorber temperature in°C
Permissible measuring energy in J
2000
1000
3000
100
400
25°C Ambient temperature
Max. energy input
Min. energy input
The measuring range varies with the ambient tem-
perature. Especially when measuring small energies
(<400J), the absorber temperature should be close to
the ambient temperature in order to achieve the highest
possible measuring accuracy.
Fig. 8.5: Measuring range as a function of the absorber temperature
The minimum energy input indicates the lower limit values with which measurements can still be performed
within the specified accuracy. The maximum energy application value specifies the limit at which the absorb-
er reaches its permissible limit temperature. The energy, e.g. for multiple measurements (repetitive measure-
ments) can be distributed across the range shown in green.
If the absorber temperature is higher than 80°C, it won’t be possible to take any further measurements.
In this case, please wait until the absorber temperature has fallen below 50°C (depending on the selected
energy input).
If a high repetition rate is prioritized over the uncertainty of measurement, a lower energy per measurement
may be used, e.g. down to 200J.
Please take the thresholds from Fig. 8.5 on page39, Tab. 8.1 on page40 and Tab. 8.3 on page41.