Installing/Mounting
4.1 Fitting the CU to the PM
Control Units CU240S
30
Operating Instructions, 07/2008 - FW 3.2, A5E00766042B AD
Figure 4-1
Fitting the control unit to the power module
24 V power supply
Normally the CU is supplied with 24 V from Power Module. But it is also possible to use an
external DC 24 V supply (20.4 V … 28.8 V, 0.5 A). It must be connected to the Control Unit
terminals 31 (+ 24 V I
n
) and 32 (0 V I
n
). Some reasons for using an external 24 V power
supply are:
● The PROFIBUS DP interface is required to communicate with the Control Unit when the
Power Module line power is not present
● Supply for 24 V encoder.
CAUTION
Care must be taken to ensure that the 24 V DC power is connected correctly or damage
to the Control Unit may occur.
Max. cable length on 24 V DC power supply and I/O cables connected to CU must not
exceed 10 m.
Use of unscreened cables is possible, however we recommend the use of screened
cables, in order to fulfill the EMC requirements for the CE marking and fail-safe products
(CU240S DP-F).
Note
If the CU is externally powered with 24 V DC but the power module is disconnected from
the mains supply, the faults F00001 … F00028 are not generated.
