Appendix
A.4 Response times
ET 200pro distributed I/O system
Operating Instructions, 03/2013, A5E00335544-08
509
A.4.6
Response times for analog input modules
Conversion time
The basic conversion time depends directly on the conversion method of the analog input
channel (integrating method, actual value conversion). The integration time of integrating
conversions has a direct influence on conversion times. The integration time depends on the
interference frequency suppression.
For information on the basic conversion times and additional processing times of the
individual analog modules, refer to the technical specifications of the corresponding analog
electronic modules.
Cycle time
The analog/digital conversion and the transfer of the digitized measured values to memory or
to the backplane bus take place sequentially. In other words, the analog input channels are
converted one after the other. The cycle time, i.e. the time until an analog input value is
converted again, is equivalent to the sum of the conversion times of all active analog input
channels of the analog input modules. Unused analog input channels should be disabled in
the parameter settings in order to reduce the cycle time. The conversion and integration time
of disabled channels is 0.
Note
With the 4 AI TC High Feature electronic module, the cycle time increases by 1× conversion
time in the case of temperature compensation involving RTD (0).
The figure below provides an overview of the cycle time elements of an n-channel analog
module.
Figure A-32 Cycle time of analog input modules
Settling time
See
Smoothing
.
