drbitboy
Lifetime Supporting Member
It does appear the the pressure sensor (IFM PN7671) that the OP mentions can send pressure via the "IO-Link" open standard. Also there are A-B AOIs for reading data (via fieldbus - is that the right term?) from a Master IO-Link device. I don't know if that is enough to get a pressure value from the sensor into the PLC; perhaps someone with better skills querying The Google can figure that out. [Update: this was the same info @Snyd1 found]
It does not solve the problem of the solenoid valve being digital.
Why not set the source hydraulic pressure at or slightly above the target value (2150PSI)? So when the valve is opened the axle would start to move toward the bushing, but the IFM PN7671 sensor-measured pressure would not rise much until the axle reached the bushing. Once it reached the bushing, then the pressure would rise until the bushing or whatever was seated and the measured pressure equalized with the system pressure, the pressure sensor switch would change state to indicate that was the case (or close, say 2145PSI to allow for noise). That switch state change would start a 10s timer, and when the timer expires the PLC toggles the valve to release the pressure.
It seems to me that without the PLC this might be designed as a manual process that operates in essentially the same way: an operator presses a momentary push button to open the valve, waits for the sensor to change state, counts to 10 when it does, and then releases the button.
I am only guessing, we don't have a complete description of the process (typical thread), and this still does not address any safety issues.
It does not solve the problem of the solenoid valve being digital.
Why not set the source hydraulic pressure at or slightly above the target value (2150PSI)? So when the valve is opened the axle would start to move toward the bushing, but the IFM PN7671 sensor-measured pressure would not rise much until the axle reached the bushing. Once it reached the bushing, then the pressure would rise until the bushing or whatever was seated and the measured pressure equalized with the system pressure, the pressure sensor switch would change state to indicate that was the case (or close, say 2145PSI to allow for noise). That switch state change would start a 10s timer, and when the timer expires the PLC toggles the valve to release the pressure.
It seems to me that without the PLC this might be designed as a manual process that operates in essentially the same way: an operator presses a momentary push button to open the valve, waits for the sensor to change state, counts to 10 when it does, and then releases the button.
I am only guessing, we don't have a complete description of the process (typical thread), and this still does not address any safety issues.
