Product Description:

The 7DI138.70 is a discrete input module produced by B&R Automation for the System 2003 Controllers series. It brings ten sink-type inputs to a control rack, allowing field devices to report status or high-speed events directly to the CPU. Used in industrial automation, the unit converts control-voltage signals from sensors, proximity switches, or encoders into logic levels that the controller can evaluate for sequencing, counting, or monitoring tasks. This mix of standard and high-speed inputs suits equipment that combines simple on/off sensing with pulse-based feedback.

The card accepts a rated supply of 24 VDC and supports input activity up to 40 kHz on its first two channels, enabling pulse counting from fast rotating machinery. Each count is stored in a 16-bit register, so a single channel can accumulate up to 65,535 transitions before rollover. All ten terminals share a common sink circuit, so the module expects the switching device to pull the line to ground. The unit provides 10 logical points, and channels 5 and 6 support frequency capture at 20 kHz. These two channels draw 8 mA @ 24 VDC, while the remaining inputs load the source at 5 mA, which helps reduce sensor loading in typical wiring layouts.

Signal integrity is maintained within an 18 to 30 VDC range, and the module recognizes a valid high signal at 18 VDC, which helps reduce noise-related miscounts. Channels 5 and 6 react quickly with an input delay limited to 3 µs maximum, while the other inputs use a 1.3 ms delay to help filter contact bounce. That short response time helps the module detect brief pulses without applying the slower filter used on standard inputs. Total internal losses remain under 0.4 W maximum, so the module adds little heat inside a crowded control panel.