The 8170+ single loop controller is part of the Plus series range and has 3-point stepping control designed specifically for open loop, valve motor drive (VMD) applications.
The 8170+ incorporates advanced tuning algorithms, with selectable pre-tune and self-tuning for easier setup. The self-tune also reduces output activity to an absolute minimum without compromising control quality, thereby reducing wear and tear on mechanical components such as valves, contactors, and relays. For example, these controls have cut down valve oscillation from 30 to 40 times a minute to just a few in the test. Pre-tune plus self-tuning has also been shown to get on control up to 3 times faster.
In addition to the VMD outputs, which can be designated as outputs for alarms, 24 VDC transmitter power supply, retransmit process value, or setpoint.