Here are my parameters:
-#17: SoftStart
-#18: 30s
-#19: 70%
-#20: 350 %FLC
@jraef: yeah, it seems to be across-the-line start...
OK, so here is what might be going on. robertmee is right, it may be related to the initial voltage setting, #19. A soft starter only controls voltage, not speed (contrary to popular belief). It can control current, and thereby torque, but it does that by controlling voltage. What
affect that has on the motor
acceleration is wholly dependent upon LOAD on the motor. So if the load is very light, even a fraction of the available torque from the motor may be enough to accelerate it faster than you want it to. This can sometimes be the case on mixers, if the mixing process involves a large change in viscosity. The motor torque capacity is selected based on the MAXIMUM viscosity that will be present at the END of the mixing process. When you first turn it on with only the base liquid in the vat, the motor is doing no real work compared to that final necessity. With the initial voltage set to 70% and the Current Limit (#20) set to 350%, it could be that because there is very little load on the motor at first, that motor torque is still much higher than the load needs to accelerate, so it accelerates immediately.
If you really think it is accelerating too fast, you can try turning the Initial Voltage down to a very low value, say 10%. All you want the Initial Voltage setting to do is to BEGIN rotating the shaft, even a tiny amount. Then as the ramp profile begins, it will accelerate it more slowly. If it still accelerates too fast for you, lower the Current Limit setting to slow it down. Just be aware that if you have a power loss when at the higher viscosity, the lower limits may cause it to stall. That starter has Dual Ramp profiles available, you could set up a "Start-Loaded" Start-Unloaded" condition response if it's a problem, but that means having some way to sense that condition. But before you go there, check with the machine designer. It might be that nobody worried about how fast it starts unloaded, they only have the soft starter there for what might happen if it has to RESTART when at higher viscosity.
PS: and yes, if Kick Start is enabled (#22-23), then turn it off, there is no need for it on this. The factory default is Disabled.
