How to apply a continuous voltage by PTM

I'm learning the PTM recently, but It's confusing me that how to apply a continuous voltage by PTM. Below is my code but it seems not works as what I want. I just want to apply a gate voltage on SMU1 and continue the voltage for the delay time, then measure the V/I/R.

forcev(SMU1, GateV_stress)
            forcev(SMU2, 0)
            forcev(SMU3, 0)
                        
            delay(int(SweepDelay * 1000))
        
            GateI_tmp = intgi(SMU1)
            GateV_tmp = intgv(SMU1)
            GateV.append(GateV_tmp)
            GateI.append(GateI_tmp)          
            GateR_tmp = GateV_tmp / GateI_tmp
            GateR.append(GateR_tmp)