The PT321MB by PT Limited is a compact weigh filling controller designed for automated filling machines in industrial packaging applications. OIML R76 Class III certified to 10,000 scale intervals, it combines high-speed conversion (up to 1,600 conv/s) with Modbus RTU communication for direct PLC and SCADA integration.

What filling modes does the PT321MB support?

Seven configurable filling modes cover common dispensing scenarios: coarse/fine dual-speed fill, single-speed fill, and combinations suited to liquid, powder, granule, and bagging applications. Adaptive filtering provides fast settling after material impact, maintaining high display resolution during dynamic filling and precise cut-off at target weight.

How does Modbus RTU integration work?

The PT321MB variant includes Modbus RTU protocol over RS-485 (in addition to standard RS-232C), enabling direct register-based communication with PLCs, HMIs, and SCADA systems. Setpoint values, fill parameters, and tare commands can be read and written remotely — allowing recipe management and production data logging from the control system without operator intervention at the panel.

How is the PT321MB calibrated?

The controller supports vCal — electronic calibration without physical test weights — using the known load cell sensitivity (mV/V) and capacity. This is particularly useful for large hopper and silo installations where placing test weights is impractical. Traditional span calibration with certified weights is also supported for legal-for-trade verification.

How is the PT321MB installed?

The compact aluminium body with stainless steel front panel is designed for panel-mount installation in control cabinets. The front panel provides a clear weight display and tactile keypad for local operation. IP65-rated front protection allows use in washdown environments common in food, beverage, and chemical filling operations.