BECKHOFF EK1914 - Manual (Page 28)

Operation
26 EK1914
Permitted cable length - outputs
When connecting a single actuator via its own continuous cabling (or via a sheathed cable), the maximum
permitted cable length is 100 m.
Attention
Route the signal cable separately
The signal cable must be routed separately from potential sources of interference, such
as motor supply cables, 230 V
AC
power cables etc.!
Interference caused by cables routed in parallel can influence the signal form of the
test pulses and thus cause diagnostic messages (e.g. Open Load errors).
The common routing of signals together with other clocked signals in a common cable also reduces the
maximum propagation, since crosstalk of the signals can occur over long cable lengths and cause
diagnostic messages. If connection via a common cable cannot be avoided, the test pulses can be
switched off (parameter: “Testing of outputs active”). However, this then leads to a reduction in the
degree of diagnostic cover when calculating the performance level.
The use of contact points or plug connectors in the cabling similarly reduces the maximum expansion.
The typical length of a test pulse (switching from 24 V to 0 V and back to 24 V) is 300 µs to 800 µs, but
can also be longer in individual cases. Testing usually takes place 3 to 6 times per second.