Can you fit a double acting valve so the fixture needs to get a clamp and unclamp signal ? Once clamped the valve spool will stay in the clamped state until the next unclamp signal, after e-stop is reset. You will need two spare M codes to operate these outputs from within a macro. The spare M codes are PLC outputs. You may need to buy the extra M codes including output driven relays and wiring from the OEM.