Selecting Digital Filtering - Siemens SIMATIC 505 Installation And Operation Manual

Selecting Digital
Filtering
SIMATIC 505–2556 Installation and Operation Guide
Locate the Digital Filtering Jumper JP67. To enable digital filtering, set the
jumper in the "ENABLED" position. Since many analog input signals
contain noise, Siemens recommends using digital filtering unless maximum
response time is required. Digital filtering applies to both thermocouple or
millivolt inputs.
The time step for digital filtering is .080 seconds. The filtering technique
used provides that the full range of a voltage change reported to the PLC
will be accomplished in 5 time steps or .40 seconds. The voltage change will
be reported as a continuous exponential function over this time period with
values at each time step as indicated
at .08 seconds, the value is 63% of full range
at .16 seconds, the value is 86% of full range
at .24 seconds, the value is 95% of full range, and
at .40 seconds, the value is 99% of full range.
Installation 2-5