The Foxcroft FX-8500 controllers provide PID set point control of chlorine, pH or any other chemical being fed into a process stream.
Use the FX-8500-S single loop controller for set point control in a closed loop process with consistent flow rate.
Use the FX-8500-C compound loop controller for set point control in a process with variable flow rates.
Either model includes a digital two line display of the process variable or set point and output as well as a single 4-20mA output. It comes in a heavy duty fiberglass NEMA 4X wall mount enclosure.
To minimize overshooting the target residual, time compensation is set to match the process time interval between chemical injection and the downstream sample result displayed at the residual analyzer. For the most responsive control the process time should not exceed 10 minutes.
The digital module includes programmable reverse or forward control mode typically used for chlorine and dechlorination systems.A variety of options are available including additional 4-20mA output, auxiliary inputs and outputs, as well as remote control (of the digital module only) of data parameters.
The FX-8500-C compound loop controller consists of a microprocessor based controller and an analog summator circuit board. This board accepts two 4-20mA signal inputs from a residual analyzer and flow meter, and combines them into a single output to control a pump or valve.
There is a ratio adjustment of the strength of the two inputs, such as 50/50, 80/20 or 75/25. For example, 75% of the output signal control can be based on the residual while 25% is based on flow rate.
The summator board includes a "no flow cutoff" that will set output to 4mA in a no flow condition. You can also select between residual control only, flow control only or compound loop flow and residual control.