gary.houston
Member
Hi All !
I am having a problem with a pressure/vfd controlled water irrigation system.
The basic set-up is a danfoss 2 wire pressure tx 4-20mA
linked directly to an abb acs350 vfd onto AI2.
AI1 has a fixed reference 7.6mA
2x digital inputs are connected to DI2 and DI5 (pid)
The problem is that when the external controller which controls the vfd start/stop function ALL of the vfd digital inputs have 24v present.
When the input to DI2 and DI5 is OFF (0v) ALL the DI's return to 0v.
Obviously, if all the DI's are receiving an input then the drive logic will hang.
I suspect a faulty vfd, but all the DI's should be internally protected from short circuit etc.
Is there a PNP/NPN switching function I have missed ?
Any help appreciated
Many regerds
Gary
I am having a problem with a pressure/vfd controlled water irrigation system.
The basic set-up is a danfoss 2 wire pressure tx 4-20mA
linked directly to an abb acs350 vfd onto AI2.
AI1 has a fixed reference 7.6mA
2x digital inputs are connected to DI2 and DI5 (pid)
The problem is that when the external controller which controls the vfd start/stop function ALL of the vfd digital inputs have 24v present.
When the input to DI2 and DI5 is OFF (0v) ALL the DI's return to 0v.
Obviously, if all the DI's are receiving an input then the drive logic will hang.
I suspect a faulty vfd, but all the DI's should be internally protected from short circuit etc.
Is there a PNP/NPN switching function I have missed ?
Any help appreciated
Many regerds
Gary