BECKHOFF EP1908 - Manual (Page 38)

Operation
36 EP1908-0002
4.5.3.6 Configuration of the EP1908-0002 for mode Two Channel Async 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 AsyncVelocity Control Channel x/y is used to determine a frequency from the
signals of an input pair of the EP1908-0002. In this mode is only the compliance with the limits for the two
channels is monitored. The upper limit frequencies are specified separately.
The two channels return logical 1 if both frequencies are below the frequency set under Velocity limit
channel x/y.
If the current frequency of the two channels is below the set limit frequency (Velocity limit channel x/y) for
the respective channel, the corresponding input pair returns a logical 1. If the current frequency of a
channel is above the set limit frequency for this channel, 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 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 Async Velocity 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: