The SI coughed up a big penalty and was blacklisted from the plant for ever. Luckily nobody was underneath and no loss of life. One day the SCADA station froze, the crane grab suddenly opened up and dropped a heavy block weighing 600kg from a height of 15ft. I would like to mention an incident where a senseless SI implemented certain command control interlocks for a huge crane system on the SCADA station. 'What if the HMI/SCADA crashes or communication with PLC fails?'.Ībove all, there must be an emergency stop button near the operator control panel. The first question to be answered in any HMI/SCADA command control design is:
For the clamp to make it to WORK position from HOME, the button must be HELD. This is why having a command that unlocks the bit as soon as the action is finished on the HMI would end up Jigging the clamp back and forth. they require a momentarily energized bit to complete their Home/Work motions.
To my understanding the cylinders we’re actuating are not automatic.
