5
1.0 Introduction
The DC4000 is a microprocessor-based conductivity controller. It is designed for use in a variety of water treatment
applications requiring precise control of total dissolved solids and chemical feed. Among its many uses, the DC4000
will control conductivity and chemical feed in cooling towers, closed loop systems, and boilers.
LMI’s DC4000 Series of conductivity controllers allows the greatest programming flexibility for cooling tower or boiler
system applications. This is accomplished through the use of an options menu that is easy to use.
BLEED or BLOWDOWN of system water by valve control can be based on several setpoint options:
• Conductivity setpoint
• Hysteresis delay (lower than setpoint) to avoid valve operation chattering
• Rising or Falling conductivity trip points
FEED of chemical (inhibitor) can be based on four (4) different methods:
• FEED at the same time system BLEEDS (lockout timer limits maximum FEED time)
• FEED time calculated as a percentage of total BLEED time
• FEED based on a timed cycle (pump is on for a percentage of this timed cycle)
• FEED based on flow meter input
ALARM indicators and relay outputs are energized based on the following conditions:
• HIGH conductivity set point is reached
• LOW conductivity set point is reached
• NO FLOW condition exists (flow switch must be installed)
The display is a 16-character backlit LCD (liquid crystal display) which is visible in all light conditions. A three-key
position membrane is used to enter data and settings (see Figure 1). The conductivity range is 0 - 20,000 µSiemens. The
units can be either µSiemens or PPM/TDS (total disolved solids). If the units displayed are PPM/TDS, the ratio of µS:
to: TDS can be selectively programmed.
All setpoints and parameter settings are retained permanently in a special nonvolatile computer chip memory, preventing
their loss due to a power outage. This nonvolatile memory chip allows the unit to be programmed before installation. No
battery powered backup is required.
Built in test circuits are provided to test each individual relay output wiring and to allow for quick field service isolation
of faulty probe, circuit cards, pumps, or solenoid valves for ease of troubleshooting.
A display for temperature is also provided. The range is 32° F to 212° F [0° C to 100° C]. The display can be either
fahrenheit or centigrade. This reading also provides the basis for temperature compensation which is performed in all
modes except the boiler mode.
A 4-20 mA analog data (or control) output is provided. The conductivity reading that corresponds to minimum and maxi
-
mum analog signals is fully programmable. This signal can be used to power chart recorders or other pumps and devices.
(866) 433-6682 • (281) 359-8538 • [email protected] • www.novatech-usa.com
