Dear sir ,

Here we use three PH-Gen-IV to take load of a conveyor system.

Load sharing logic was written in AB-PLC system .

I changed one spare DCR box for testing purpose.

When I test it in Noload in a single motor ,there was no fault .

1. but when I used it in load with conveyor , this drive couldn't share load , means the Iqs was high . it took high torque . and other 2 drive took low load so system was tripped by PLC logic "torque difference " .

After that I checked that and found, The Speed demand was 0.4 instead of 0.0 . I changed only the Hardware span of Analog In1 (2818) 1.0960 to 1.0830 . As same result the input current 4.8mA was changed to 4.09mA .

Then the Torque difference problem was eliminated .

2. After then , we gave command to decrease the belt speed at scada, the all three VFD got speed increase command and their speed demand was increasing automatically .

Then we checked the Speed feedback parameter and changed the Hardware Span(2844) of Int Analog Out1 (2845) from 0.9800 to 1.0150 for 3.88 mA to 3.99 mA.

After that we again download the PLC backup .

Then the speed increasing instead of decreasing problem was solved .

3. Then when we reached the speed of 75% again same problem happened. VFD- 2 took low torque and VFD-1 and 3 took high torque .

Then I changed all five OLD card of DCR box except back panel and SMPS and set the old harware span of both AI and AO. then I checked the system in full speed 4.8m/s means 90% speed demand . there was no error .

Then I again checked the new cards of DCR box one by one . At last I found when I connect the System I/o board and changed the Hardware span then same problem was happened.

4.Then it was decided that we used the OLD System I/O board with NEW DCR box and checked it again. means we only swapped the System I/O board from New DCR box .

After that we run the system in full load and full speed . there was no torque difference and no fault .

But question was arise "Is there Any problem in new System I/o board ?"

Also the firmware .REV of NEW System I/O different from OLD System I/O board .
NEW System I/O board Firmware:- A1A10000423.00M REV BM
OLD System I/O board Firmware:- A1A10000423.00M REV BL

How to calibrate AI an AO by using hardware span and min input (ID :- 2818 and 4120)

Please suggest me how to fix the issue . I think there is no problem in new System I/o board . There was some point , missed by me So need your help .

Please do the needful regarding above matter .

Thanks and Regards
SWA1989