Siemens Simatic S7-400 - Manual (Page 352)

Analog Modules
5-136
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Table 5-74 Parameters of the SM 431; AI 8 16 Bit, continued
Parameter Scope Parameter
Type
Default 2) Value Range
•
Smoothing None
Low
Average
High None
•
Reference junction
(reference to the cold
junction) None
Internal
Reference temperature value dynamic Internal Static Module
1) If you use the module in ER-1/ER-2, you must set this parameter to “No” because the interrupt lines are
not available in ER-1/ER-2.
2) Only in the CC (central controller) is it possible to start up the analog modules with the default settings.
3) The limit values must be within the temperature range of the connected sensor.
4) Valid for the format of the output temperature and the dynamic reference temperature
Smoothing of the Measured Values
You fill find information that is generally applicable to the smoothing of analog
values in Section 5.6.
The cycle time of the module is a constant in the SM 431; AI 8 16 Bit that is not
dependent on the number of channels that are enabled. It therefore has no effect
on the step response, which is defined by the parameter assignment of
interference frequency suppression and smoothing.
Step Response
Table 5-75 How Response Times Depend on the Parameterized Interference Frequency Suppression
and Smoothing of the SM 431; AI 8 16 Bit
Interference Frequency
S pp essio i H
Response Time in ms with Parameterized Smoothing:
Suppression in Hz
None Low Average High
10 100 200 1600 3200
50 20 40 320 640
60 16.7 33.3 267 533
400 10 20 160 320
The following figures illustrate the contents of Table 5-75. They show the response
time required for a step response before the smoothed analog value is almost
applied to 100%. The figures apply to every change of signal at an analog input.