For all Irinos systems, the real-time capability is independent of the number of probes (measurement channels), since each Irinos box has its own measurement value buffer. With the
•Irinos IR, most boxes are able to acquire 20000 samples/s, and with the
•Irinos EC, most boxes are able to acquire 4000 samples/s.
Two quick rules of thumb for 99% of applications are:
•If you limit the sampling speed to 1000 samples/s, there is no need to think about any details. Or:
•If you limit the sampling speed to 10000 samples/s and if you have a maximum of 4 Boxes, there is no need to think about any details.
(With the Irinos EC, the max. speed still is 4000 samples/s.)
The sampling period used with the NMX DLL must be an integer multiple of the minimum sampling period of the system. The following table lists typical sampling speeds:
Sampling Speed [samples/s] |
Sampling Period |
Irinos IR |
Irinos EC |
20.000 |
50 µs |
OK |
not supported |
10.000 |
100 µs |
OK |
not supported |
6.666 |
150 µs |
OK |
not supported |
5.000 |
200 µs |
OK |
not supported |
4.000 |
500 µs |
OK |
OK |
2.000 |
500 µs |
OK |
OK |
1.000 |
1000 µs = 1 ms |
OK |
OK |
500 |
2000 µs = 2 ms |
OK |
OK |
200 |
5000 µs = 5 ms |
OK |
OK |
100 |
10000 µs = 10 ms |
OK |
OK |
The memory is dimensioned so that the measured values can be buffered for at least 10 seconds at the maximum sampling rate. If the sampling rate is lower, this time increases accordingly.
Only the transmission time to the PC depends on the number of channels and the measuring rate. Since the data transmission to the PC and the PC itself do not have realtime capabilities, no guaranteed transmission time can be guaranteed. However, typically a transmission rate can be achieved, which is almost constant and thus close to realtime.
For time-limited real-time measurement, the transmission rate is relevant for calculating the typical time between "start of sampling" and "all measurement data available on the PC". This time is called "transfer time".
For endless measurement, the transmission rate is relevant for determining the maximum possible sampling speed.
Typically achievable transmission rates are listed in the following table:
Irinos System |
Typical transmission rate RTR-32 with 32 Bit measurement channels, e.g. Incremental probes |
Typical transmission rate RTR-16 with 16 Bit measurement channels e.g. Inductive probes |
Irinos IR |
approx. 200.000 values/s |
approx. 400.000 values/s |
Irinos EC |
approx. 80.000 values/s |
approx. 160.000 values/s |
As shown in the table, the transmission rate also depends on the native data type(s) of the measurement channels used. If mixed types of measurement channels are used, then the typical transmission rate will be in between the given values.
Some examples are provided here to give a quick guidance. For a detailed examination, calculation formulas are given below.
Examples for Transfer Time for a time-limited sampling with a duration (Start -> Stop) of 10 seconds:
Configuration |
Irinos IR |
Irinos EC |
32 Inductive Probes |
10000 samples/s: 10s + 0s = 10s -> Similar to realtime |
4000 samples/s: 10s + 0s = 10s -> Similar to realtime |
32 Incremental Probes |
10000 samples/s: 10s + 6s = 16s -> approximately 6 seconds after stop, the transfer is finished |
4000 samples/s: 16s + 6s = 16s -> approximately 6 seconds after stop, the transfer is finished |
32 Inductive Probes (16 Bit) + 4 Incremental Probes (32 Bit) |
10000 samples/s: 10s + 0s = 10s -> Similar to realtime |
4000 samples/s: 10s + 0s = 10s -> Similar to realtime |
16 Inductive Probes (16 Bit) + 16 Incremental Probes (32 Bit) |
10000 samples/s: 10s + 2s = 12s -> approximately 2 seconds after stop, the transfer is finished |
4000 samples/s: 10s + 2s = 12s -> approximately 2 seconds after stop, the transfer is finished |
Examples for maximum sampling speed for endless sampling:
Configuration |
Irinos IR |
Irinos EC |
32 Inductive Probes |
Theoretical maximum: 12500 samples/s Next possible value: 10000 samples/s Recommended: ≤ 6666 samples/s |
Theoretical maximum: 5000 samples/s Next possible value: 4000 samples/s Recommended: ≤ 2000 samples/s |
32 Incremental Probes |
Theoretical maximum: 6250 samples/s Next possible value: 5000 samples/s Recommended: ≤ 4000 samples/s |
Theoretical maximum: 2500 samples/s Next possible value: 2000 samples/s Recommended: ≤ 1000 samples/s |
32 Inductive Probes (16 Bit) + 4 Incremental Probes (32 Bit) |
Theoretical maximum: 10000 samples/s Next possible value: 10000 samples/s Recommended: ≤ 6666 samples/s |
Theoretical maximum: 4000 samples/s Next possible value: 4000 samples/s Recommended: ≤ 2000 samples/s |
16 Inductive Probes (16 Bit) + 16 Incremental Probes (32 Bit) |
Theoretical maximum: 8333 samples/s Next possible value: 6666 samples/s Recommended: ≤ 5000 samples/s |
Theoretical maximum: 3333 samples/s Next possible value: 2000 samples/s Recommended: ≤ 2000 samples/s |
64 Inductive Probes |
Theoretical maximum: 6250 samples/s Next possible value: 5000 samples/s Recommended: ≤ 4000 samples/s |
Theoretical maximum: 2500 samples/s Next possible value: 2000 samples/s Recommended: ≤ 1000 samples/s |
# Formulas
Following a few formulas are provided to get estimations. These formulas use the following variables:
Variable |
Meaning |
Unit |
tTransfer |
Transfer Time: |
s -> seconds |
tSampling |
Sampling Time: |
s -> seconds |
vsMax |
Maximum sampling speed for endless sampling |
values / s / channel --> same as: samples / s |
RTR |
Typical Transmission rate, see table above. |
values / s |
NMCH |
Number of measurement channels used |
channels |
NMCH-16 |
Number of 16 bit measurement channels used |
channels |
NMCH-32 |
Number of 32 bit measurement channels used |
channels |
NSamples |
Total number of samples to be recorded |
values / channel |
Each formula is provided in a simplified form and in a detailed form.
The simplified form is sufficient for most applications as a quick check.
The detailed form is especially used, when very high performance is required.
Required value |
Simplified |
Detailed |
Transfer time for time-limited sampling (Time between "start of sampling" and "all measurement data is available at the PC") |
Formula 1:
Note: tTransfer is always ≥ tSampling |
Formula 2:
Note: tTransfer is always ≥ tSampling |
Max. sampling speed for endless sampling |
Formula 3:
|
Formula 4:
|
Example for Formula 1:
In the measurement application with the Irinos IR, 21 inductive probes, 4 analogue channels and 3 incremental probes/encoders are used. The measurement has a duration of 5 seconds at 10000 samples/s.
NMCH = 21 + 4 + 3 = 28 channels
NSamples = 5s * 10000 values/s/channel = 50000 values/channel.
RTR-32 = 200000 values/s
--> 2 seconds after stop of sampling, all data is available.
Example for Formula 2:
In the measurement application with the Irinos IR, 21 inductive probes, 4 analogue channels and 3 incremental probes/encoders are used. The measurement has a duration of 5 seconds at 10000 samples/s.
NMCH-16 = 21 + 4 = 25 channels
NMCH-32 = 3 channels
NSamples = 5s * 10000 values/s/channel = 50000 values/channel.
RTR-16 = 400000 values/s
--> Since tTransfer < tSampling, all data is available immediately after stop of sampling.
Example for Formula 3:
In the measurement application with the Irinos EC, 11 inductive probes + 1 incremental encoder are used.
NMCH = 11 + 1 = 12 channels
RTR-32 = 80000 values/s
--> The maximum speed of the Irinos EC, which is 4000 samples/s, can be used.
Example for Formula 4:
In the measurement application with the Irinos IR, 31 inductive probes + 6 incremental encoders are used.
NMCH-16 = 31 channels
NMCH-32 = 6 channels
--> 5000 samples/s can be used as maximum sample rate.