When designing a position/pressure application, is the pressure loop better regulated by a proportional valve that has a smaller maximum flow rate, so long as its full-open flow rate satisfies the application’s requirement for positioning speed? It is sometimes tempting to employ valves that are common to existing inventory stock and in general use, if they loosely fit the application. A Bosch 4WRPEH10C4B50L-2X/G24K0/A1M will provide nominally 50 liter/min. For my small diameter cylinder, running fairly slow positioning speeds, 50 l/m is more than adequate. My most commonly stocked valve, however, is a Bosch 4WRPEH10C4B100L-2X/G24K0/A1M (0 811 404 803), which is 100 liter/min. Do I risk losing control granularity when I switch to pressure/force control if I employ the higher flow rate valve? -thanks
Yes, a valve that is too large can cause problems, but it depends on your application specs. And direct drive (single stage) valves are generally more forgiving. We have a zerolap linear single stage 100 L bosch valve on a 2 in. bore cylinder and it controls position and pressure very well.