PCB Functional Test Services

For the Industrial Control and Electromechanical FCT application family, SUGA's FCT for a 24 V control board can emulate logic input signals, 4–20 mA analog signals, interlocks, relays, valves, contactors, motor-equivalent loads, and RS-485, CAN, Ethernet, or product-defined communications. One risk is that a driver may pass a cold, no-load check but become degraded or fall out of specification under its actual coil load and duty cycle. FCT can also capture input-threshold errors, missing flyback protection, improper I/O mapping, and unsafe recovery after interlock or watchdog events. The test records startup sequence, I/O state, loaded output, messaging, alarms, and reset operation.

Vehicle, agricultural, and off-highway boards require evaluation of ignition states, battery voltage levels, crank or dropout conditions, wake and sleep transitions, sensor states, switch states, and actuator states. SUGA's FCT can test CAN and LIN output-driver performance, diagnostic messages, protection behavior under defined load conditions, quiescent current after entry into sleep mode, and recovery after power interruption. A costly failure is typically not a driver fault, but a board that wakes on the wrong CAN frame or does not fully enter sleep mode, continuously depleting the battery over several days rather than a few seconds. This makes wake-source and quiescent-current checks more important than output-load testing in this application.

Most aerospace, defense, and navigation PCBAs require controlled power sequencing, sensor or positioning inputs, data buses, control outputs, alarms, redundant-path checks, and hardware and firmware identification. The sequence captures deterministic timing, bus response, fail-state behavior, stored configuration, and recovery from an interrupted power or communication condition. These products are susceptible to two primary risks: a revision mismatch may produce a valid reading against the wrong configuration, and testing a redundant channel individually does not guarantee that the system will function correctly in failover mode once the primary path is removed.

Medical-monitoring and patient-monitoring PCBAs use calibrated signal or sensor simulators to test acquisition channels, alarm thresholds and latching, displays, keys, communication capabilities, battery changeover, charging states, and fault indications. An alarm that clears itself without required operator acknowledgement is a life-safety failure rather than a cosmetic failure, so the latching function requires a separate verification step instead of relying on a general pass/fail screen check. The records link the tested input conditions to the channel results, alarm response, firmware, and unit identity.

Known calibrated inputs are required to test analog front ends, ADCs, DACs, multiplexers, isolated channels, and digital interfaces. FCT checks gain, offset, range switching, channel-to-channel consistency, calibration-data access, display, and communication. An unstable reference or ungrounded test lead may resemble a defective board at the ADC. Consequently, the station calibration record for reference-source accuracy, settling time, grounding, and thermal drift is tied directly to the measured channel and range rather than assumed to be stable.

SUGA can load production firmware and test Ethernet, USB, UART, storage, indicators, displays, sensor inputs, and wireless links. Under power-save conditions, a board can associate with a Wi-Fi or Bluetooth peer but still fail to transmit a valid payload if the timing is incorrect. The sequence verifies actual data transfer and application response rather than only detecting connectivity. Controlled peers, coupling or RF conditions, sleep-current timing, network reconnection, firmware identity, and wake-source behavior expose issues that a typical connectivity test cannot identify.

Power conversion and lighting controls require controlled operating states for startup, output regulation, current or voltage feedback, load-step response, protection thresholds, shutdown, and restart. FCT tests these states to ensure that the board meets its specifications at the intended operating points. A board may pass under no-load conditions but fail under demand. A board may also have properly regulated output while its dimming or fault-latch circuitry is defective; a protection trip may appear to recover even when the trip threshold was never measured.

Marine and oilfield monitoring PCBAs can accept simulated pressure, temperature, flow, position, 4–20 mA, and switch inputs. FCT checks sensing, isolated I/O, relay or actuator outputs, alarms, data logging, remote communications, power-loss recovery, and watchdog restart. A board may continue operating through a brownout but still corrupt logged data or miss an alarm. Open-sensor, short-sensor, brownout, communication-loss, and latched-alarm states are therefore important for verifying field-fault behavior.