When agitated without HIAMP (i.e. with a sense resistor of 1.5Ω) current voltage at ISEN rises to 80mV (55mV at D18) within 1ms, and to 140mV (115mV at D18) within 2ms. After 3.25ms current voltage at ISEN reaches 200mV (180mA at D18) and PWM current limitation kicks in.
With HIAMP (i.e. with 0.5Ω plus 16mΩ Rdson in parallel to the 1.5Ω) voltage rises to 35mV (30mV at D18) after 2ms, to 105mV after 10ms (also on D18), and when reaching 115mV after 14ms the valve switches ON (which takes 3ms and reduces current voltage back to 80mV), then voltage rises again another 30ms to peak off at 135mV.
When switching off HIAMP and holding ON, PWM kicks in immediately on ISEN. On D18 current voltage drops from 135mV to 75mV after 2ms, and then to 35mV after 13ms, then rises again to and stabilises at 80mV within 3ms.
When switching shortly (500uS) to SLOW DECAY (IN1 H and IN2 H) during valve holding ON without HIAM, current of 130mA continues to circulate through the coil, dropping only by ~5mA. However, ISEN is detached from that current and drops to zero, and current voltage at D18 drops from 75mV to 25mV as the 100nF discharge through 2k7. Back to holding mode, current voltage recovers within 125us to 75mV as the cap charges again from ISEN which recovers within 150us from ~195mV to 200mV when PWM sets back in.
When switching shortly (480uS) to BRAKE (IN1 L and in2 L) during valve holding ON without HIAMP, D18 voltage drops within 110us to zero due to ISEN becoming negative -170mV recovering to -160mV. As ISEN recovers to -145mV in the remainder of the time, D18 drops to -110mV. Back to holding mode, ISEN rises back to 160mV and then recovers to 200mV entering PWM mode again in 660us. At that time D18 has recovered from -110mV to 170mV (crossing the zero line after 140us). Another 2ms later D18 has dropped again back to the regular 80mV.
Refer file OFF-PENG-ON-PING-PONG.sal.