BECKHOFF EP1908 - Manual (Page 37)

Operation
EP1908-0002 35
4.5.3.5 Configuration of the EP1908 for mode Two Channel Encoder Velocity Control
The TwinSAFE EtherCAT Box also supports direct connection of initiators and encoders for speed
measurement or frequency (24V DC).
The set mode Two Channel Encoder Velocity Control Channel x/y is used to determine a frequency from
the signals of an input pair of the EP1908-0002. The upper limit frequencies are specified separately, but
should but the same. The same frequencies have to be supplied, whereby all states are permitted that
may occur at the encoder interface.
If the current frequency is below the limit frequency set for both channels (Velocity limit channel x/y), the
corresponding input pair returns a logical 1. If the frequency is above the set limit frequency, the
corresponding input pair returns a logical 0.
The minimum supported frequency is 2 Hz. Values below this are shown as 0. The maximum supported
frequency is 500 Hz. Values above this result in a diagnostic message of the EP1908-0002. This
message can be reset through a rising edge of the safe output signal ErrAck of the EP1908-0002.
Parameter:
•
Connect the signals of the used sensors/encoders to input pairs 1 and 2, 3 and 4, 5 and 6 or 7
and 8
•
Switch off the sensor test for the inputs used (Sensor test Channel x active = FALSE)
•
Set the parameter "Logic of Channel x and y" to
"Two Channel SyncVelocity Control Channel x/y"
•
Set the parameters Velocity limit channel x and Velocity limit channel y of the used channels to
the required value. The entered value has the unit 1/10 Hz.
Example for a signal curve of the input signals: