The client brought DMC on board early after a staff member identified issues with past machine performance and wanted help specifying National Instruments control and Data Acquisition hardware. Our unique skill set allowed us to help bring online a complicated system with many moving parts.
Specification
DMC engineers provided platform and device options after reviewing the tight timing considerations, IO list, and system needs. We determined that an NI FPGA was the best option after ruling out the response time of leading PLC modules and estimating the number of FPGA cycles and the timing of analog output assert based on card types.
After selecting hardware, DMC also mapped out a full software design for the three separate but interconnected applications. Messaging, data exchange, and network and state diagrams were provided for programs running on the real-time target, FPGA target, and logging HMI PC.
Development & Outcome
After specification, DMC began to develop each software piece. We wrote and tested custom LabVIEW FPGA software responsible for protecting expensive high-voltage equipment before the final assembly of the RF system. Digital inputs were queried at a rate of roughly 300ns, with response times (debounce and trigger assert) hovering around 23us.
This custom FPGA software successfully replaced the client’s old detection circuitry, providing circuit changes with a few code modifications plus compile. We leveraged this flexibility by adding redundant sense lines to the routine throughout the project along with state-based reset masks and varying debounce modes.
Alongside the discrete trigger lines and rapid response, the FPGA supplies analog values to the real-time application. The real-time application, after launching the FPGA portion at boot, collects and scales a wide range of sensor data from the FPGA.
PID control, lower-speed limit alarms, and process logic are all handled by the real-time LabVIEW application. Data is sent from the cRIO chassis by the real-time program to the disk-heavy HMI PC with ample storage. Client engineers can configure slew rates, alarm limits, and power outputs on the HMI application. The HMI LabVIEW software, along with supplying a handy manual mode for local operation, can command warmup and ramp sequences.
Adding to the complexity of this solution, the cRIO program also responds to network commands from a remote line PLC. Although DMC didn’t program the PLC software in this instance, the client appreciated that we leveraged our cross-training when debugging a National Instruments and Allen-Bradley system.
Learn more about DMC’s LabVIEW programming services and contact us for your next project.