Product Description:

The 7DM438.72 module is an I/O slice produced by B&R Automation for the System 2003 Controllers series. It occupies a single slot on the system backplane and presents the controller with a mixed bank of digital input and output channels so field devices can be wired directly to the PLC task layer. Within an automation cell, the unit translates 24 V sensor or actuator levels into logic states that the CPU evaluates for sequencing, safety interlocks, or machine status reporting.

This slice provides 8 digital inputs and 8 digital outputs, giving the programmer symmetrical signal capacity for on/off devices such as proximity switches and solenoid valves. Incoming signals are accepted through a 24 VDC input rating and are conditioned by a ≤1 ms input filter that suppresses contact bounce before the values are sampled. The input circuit can be wired as a sink or source input circuit, allowing flexible polarity when connecting PNP or NPN sensors. There is isolation between each channel group and the PLC backplane, but no isolation between individual channels, so common reference points must be planned when mixing supply domains. Reverse-polarity diodes protect the input terminals from accidental power reversal, and sensor excitation must be provided by an external 24 V supply.

The output side draws a modest 0.5 W from the internal bus yet can drive loads up to 0.5 A per channel, as long as the aggregate remains within 4.0 A total output. Each high-side driver sources the field load at the same 24 V level and is guarded by a thermal cutoff that opens when excessive dissipation is detected. Output voltage transients are clipped internally, and the module has an IP20 enclosure rating, so it must be installed inside a switchgear cabinet. The outputs are source-configured, and channel-group isolation separates the field side from the PLC backplane.