Xylem PC320 Process Controller - Manual (Page 3)

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I. PC320 Process Controller Description
The PC320 Process Controller is reliable, accurate and suitable for measuring
any type of 2 and 3 wire sensors with 4-20 mA, 0-1 volt and 0-5 volt outputs.
The controller comes pre-programmed for use with 12 different common
sensor types and appropriate selectable engineering units. In addition, the
PC320 can be programmed by the user to monitor any type of custom sensor
in any user defined units. Custom user defined engineering units are also
programmable for all standard sensor types. Both 2-point and 3-point
calibration methods are supported and an additional 3
rd
order polynomial
equation can be applied to the sensor data to correct for non-linearities in
sensor output. The polynomial mode is useful for calculating other
parameters based on a sensor reading such as calculating water flow rate
from water level.
The PC320 controller is enclosed in a NEMA 4 enclosure and is easily
programmed and calibrated in the field using the water resistant 8 button
keypad and 2-line LCD display, by going through a series of simple menu
options.
The LCD display shows what type of sensor is being monitored, the data
reading averaged over a user programmable time period, and the engineering
units selected. The display also shows the current On or Off state for each of
the 4 relays. Two other display modes are available. One shows the
maximum and minimum sensor readings since last reset. Another mode
displays the current state of any of the 4 relays in real time, the sensor
reading that caused the last triggering event, and the On or Off time
remaining in the control cycle. The LCD display can be backlit for easy
viewing at all times and offers a power saving mode for limiting current
drain in battery powered applications.
Four relays are provided for controlling external devices including samplers,
alarms, mixers, pumps, control valves, floodgates and telemetry systems.
Each relay is independently programmable to trigger on maximum and/or
minimum threshold levels in one of five different control modes.
Relay operation is defined by setting upper and lower sensor threshold levels
and turning relays on when sensor readings exceed a normally defined range.