Now we have ruled out the use of a counterbalance vale in our system, we need to find a suitable slice valve to lock the leg when the system is switched off. However, with a slice/poppet valve the system could be prone to pressure intensification issues, therefore we would also require and additional dual sandwich relief module per axis, which would be a hefty 3 valve cetop 3 stack!
Fortunately we have found a solution that should incorporate the slice and relief functions into one sandwich valve. This is special manifold from Sun, which uses two T-21 cartridges to control flow through A and B, with a pilot line controlled through a T-9 cartridge. This means we could use counterbalance valves, piloted from P through a solenoid valve. The counterbalance valves will give us our pressure relief function when the system is off, and the solenoid control will allow us to enable one axis at a time, so we can remove the manifold isolation valve.