There are 2 Duty/Standby pump motor driven by 2 AB PowerFlex 40 VFDs, the operation conditions shall be same as similar propose for these. But, it is found that "Digital In1~4 Sel A051~A054" in both VFD are set with different value by supplier, I assumed that it is incorrect, am I right?

I tried to study the Manual of PowerFlex 40, but it is hard to understand the description of these Digital In 1~4, if any one can help me to understand it?

The setting of A051~A054 in VFD A are: 4, 4, 5, 11;
The setting of A051~A054 in VFD B are: 6, 0, 5, 11;

Tks.

Yes I can understand the settings

The two VFDs as described are setup differently. Without very detailed information its hard to see why. I wouldnt expect to se them that different without a very good reason.

anyway here goes. Both VSDs have DI3 set so that when this has a 1 on it the key pad becomes the local control IE the speed and start/stop are controlled by the ketpad.

Also both VSDs are set up for DI4 to be a jog forward button and the drive will ramp up to a frequency set by A078 at a ramp set by AO79 when DI4 is 1. When DI4 becomes zero the drive will ramp back to zero frequency.


For Drive A Digital inputs 1 and 2 both set to preset frequency input.
If either of these inputs are raised to 1 the the drive will run at a preset frequency.

For Drive B Digital 1 will will enabvle the start sto and frequency to be controlled via the serial port and digital 2 is diabled (not used).

So I suspect that if you look at your drawings then the application you have will use 4 on both drives to control which pump runs. I would expect digital input 3 to be connnected in both cases to be connected to remote/local control switches.

Good practice would be for both drives identically proggramed and unused inputs to be disabled.



I hope this is helpful.

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Andrew Burgar BSc CEng MIET