Autorange Function; Filter - Beckhoff EL3692 Manual

Commissioning
Mixed mode
One channel measures continuously, the other only on request. This mode is a combination of the two
previous modes. Once channel measures continuously and interrupts its measurement only if a
measurement is requested on the other channel.
This mode is suitable for measuring high-resistance test specimens. Constant current flow (provided the
other channel is never activated) means that all charging processes are complete. A delay after CoE
0x80n0:31 [} 166] is therefore not required.
In single-channel mode measurement of the second channel can be triggered by writing 1 or 3 in the entry
0x80n0:0D [} 166] (mode).
Broken wire
The only way in which the EL3692 can detect a "broken wire" is therefore by registering sustained
exceedance of the measuring range ("Overrange").
In 4-wire mode, there may be combinations of wire breakage that may not result in an unambiguous
"Overrange" error and can only be detected based on sustained measured value variations in an implausible
range.
5.6.7

Autorange function

If active, the Autorange function always selects a measuring range in which a value can be displayed.
Measurements
In 2-wire mode the Autorange function does not assume values below range 2 (10-100 ohm), since
the three lower measuring ranges are not calibrated by the manufacturer. See also 4/2-wire mode.
5.6.8

Filter

In the COE (object 0x80n0:21 [} 168]) the EL3692 has a filter setting option for each channel. The principle is
as follows:
• the raw resistance value is determined in rapid sequence
• the values are averaged over time x
• the time x is determined through inversion of the set filter frequency. Example: 10 Hz --> 100 ms
averaging period
• Once the filter"time" has elapsed the determined resistance is forwarded for processing (diagrams etc.)
This process results in a notch characteristic as shown Fig. Filter characteristic. The filter frequency entered
corresponds to the smallest blocked frequency. All multiples of the specified frequency are also blocked. The
default setting "10 Hz" blocks 50 Hz and 60 Hz interference.
The filter setting has therefore direct influence on the conversion time of the respective channel.
146 Version: 3.1 EL3692