I recently had a discussion with a Machine Builder for whom we are building a PLC control. He said that he would be using 24 VDC air valves on the machine as he needed them to be fast acting. I questioned whether 24 VDC was any faster than 120 VAC. He replied that he always used 24 VDC for high speed applications.
I have never used 24 VDC valves. What do others think about AC vs. DC for fast response? I cannot find anything from the valve manufacturer (Mac) indicating one type of solenoid is faster than another.
What type of PLC output would you recommend for the 24 VDC valves, solid state or relay contact? I realize that solid state is faster and more reliable but how do they hold up with the inductive spike when the output is shut off? I would like to put free wheeling diodes across the valve coils but this would really slow down the response. How do others control DC valves?
Thanks for any comments or experiences.
I have never used 24 VDC valves. What do others think about AC vs. DC for fast response? I cannot find anything from the valve manufacturer (Mac) indicating one type of solenoid is faster than another.
What type of PLC output would you recommend for the 24 VDC valves, solid state or relay contact? I realize that solid state is faster and more reliable but how do they hold up with the inductive spike when the output is shut off? I would like to put free wheeling diodes across the valve coils but this would really slow down the response. How do others control DC valves?
Thanks for any comments or experiences.