Appendix C Notes on Applying the I/O Modules
6F8C1575
118
C.3 DC Output Modules
(1) The DC output modules require that power to drive the output transistor be
supplied externally. Connect the voltage within the rated load voltage criterion to
the predefined terminals for each of the common terminals.
(Refer to the TC-net I/O Instruction Manual: Module Individual Specification.)
If connection made with the polarity of the power supply inverted, the module may
fail. Never invert the polarity during connection.
(2) Table C.3-1 summaries the concepts of overcurrent protection coordinations of the
DC output modules.
Table C-1 DC output protection coordination
Module type
Protection coordination
DO934/DO935 Contains a 2 A fuse per common terminal. When overload or a load short
circuit has occurred, the transistor cannot be protected; however, burning
of the module or external cable is protected.
(3) On any load through which a transient overvoltage flows, the diode is installed as
shown in Figure C-10 in order to protect the transistor.
D: Bypasses the transient overvoltage to the power supply to suppress the voltage between
transistor's collector and emitter.
D
Figure C-10 DC output transistor protection
(4) Below are notes concerning the transistor protection diode and fuse blowout
detection circuit, mentioned above. Pay special attention when applying them.
<Note 1>
If connection is made to equipment that uses the internal power feeding input
method, the load current may flow through Diode D when the voltage of P1 in
Figure C.3-2 is higher than the voltage or P2 goes OFF with P1 ON. If this
occurs, the external equipment signal is input as ON regardless of the output
state of the module.
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