Posted 30 Jan 2019 (edited) I am having trouble with a HC900 C50 CPU. It’s connected to a hakki HMI and on certain instruction performed on the screen it faults out the CPU. I have 3 strobes on the led which in the manual indicates a CPU prefetch abort error. It says to replace the CPU which I have done but the fault occurs on the new one too. I have replaced the HMI and comms cable between them but nothing has helped stop the fault occurring. Any ideas on next actions welcome Edited 30 Jan 2019 by Cryan9954 PLC hep Share this post Link to post Share on other sites
Posted 5 Feb 2019 1. Did the HMI ever communicate successfully with the CPU, or is this a commissioning/start-up problem? 2. What HMI instruction faults the HC900 CPU? 3. Which version firmware is the HC900 CPU running? 4. Which hardware comm is for CPU/HMI comm? Ethernet or RS-485? 5. Is the HMI the Modbus Master, HC the Modbus slave? 6. Are the CPU’s genuine Honeywell, or the fake, knock-off made in India models? Share this post Link to post Share on other sites