Rexdale, Ontario, Canada —Series 502 suspended solids meters use ultrasonic attenuation to measure the concentration of sludges and slurries that are too thick for optical methods. According to Markland, the new higher power microprocessor-based instrument features automatic pushbutton calibration, automatic dynamic damping, and self diagnosis, and is insensitive to color. Its enclosure is NEMA-4X (IP67). Other features include liquid crystal display readout, 4-20 mA output, two set-point relays, and a serial port. Two styles of pickup heads are available. Markland Specialty Engineering Ltd.