The ABB positioner cannot reach zero after self-tuning
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Recently, several ABB - TZIDC intelligent positioners were adjusted; the equipment operates normally, and the positioners (for linear displacement) can also be self-tuned successfully. However, after the tuning is complete, the 4mA model only reaches around 0.3~1.5% of its full range. It can’t reach 0; even when fully open, it’s around 99.6%. I’m seeking guidance from experts; I suspect it’s caused by a gap between the locator feedback rod and the follow-up pin. I’m not sure if this counts as successful debugging
Acceptable! It won’t affect usage; check whether the other valve positions are accurate.
For process testing, an error of 2% for the self-regulating valve is acceptable, provided that it can be closed completely, the valve seat returns to its proper position, and there is no excessive leakage
Thank you, that puts my mind at ease. I’ll prepare to make a few more spring clips to eliminate the gap between the follower pin and the feedback arm, and see if that can bring it to zero.
Should it be determined whether the valve position is accurate based on the leakage amount from the sealing test? After all, it cannot be seen with the naked eye either.
Go to menu P7.7 to set the dead zone; it ranges from 0.1% to 10%, with 0.1% as the default value. Complete supporting documents are available.
I consulted the manufacturer’s technical staff, and they indeed mentioned this method as well. I gave it a try; the self-tuning process just wouldn’t finish, but no error was reported. The normal adjustment takes about 5 minutes to complete, but after setting the dead zone it takes 30–40 minutes yet to finish; I’m not sure if it’s because of my incorrect settings.
So how can I determine whether the valve position is accurate? Please give some guidance
Hehehe, this smart locator – from what I can see, it looks like some kind of silly gadget, doesn’t it? I guess maybe ABB isn’t good enough by nature; it’s just a smart idiot. Identification completed.