in reply to: Re: Re: Re: Command 13 Read Tag, Descriptor, Date posted by Jens on 05 September 2011 at 09:29:12.
No indeed, the PV Damping Value can be set to non-zero values by command 34 in any device which supports it. (There may be device-specific limitations on what the value can be set to.) I imagine 0 seconds would be the normal ex-factory value.
This value is a time-constant applied to smooth the measurement transducer samples, generating the digital PV, and thus it also applies to the analogue output, and the digital Loop Current and Percent-of-Range. It can be used to remove any process noise, which you wouldn't want to reach a controller. It's a single time constant, equivalent to a single R-C filter section, hence the 63% definition.
Command 64 allows an *additional* damping time constant for any analogue output, not just the PV analogue output. What the spec says is that if you do this for the PV of a transmitter (by specifying AO number code 0), it will affect the analogue output and the digital Loop Current, but *not* the digital PV itself. But for an actuator, it will also affect the digital PV.
Sorry about the Board's rejection of your first message (which I've deleted as confusing). It doesn't like quotes! Something in the Perl script thinks it's the end of the string ...