The same controller needs to work with different mold types. Some older molds use J-type thermocouples. Some newer molds use K-type. If the controller supports only one type, changing molds requires changing control cards. This adds cost and downtime.
Mold-Masters' TempMaster M3 and M4 support J-type and K-type software switching. Domestic controllers like HOTTIP and TEMCO also offer J/K conversion.
Beyond J and K, some controllers support E-type and N-type. E-type offers higher accuracy at low temperatures. N-type offers better stability at high temperatures. The more types supported, the more versatile the controller.
But note: software switching only makes the controller read the correct polynomial. The physical characteristics of the thermocouple do not change. A J-type connected to a K-type channel will still produce errors if the compensation wire in the junction box is still K-type, even if the software is set to J. When switching types, verify the entire signal chain matches.
The practical benefit is inventory reduction. A shop with mixed molds does not need to stock separate controllers for each type. One controller handles all molds. The spare parts inventory is simpler. The maintenance team needs only one type of controller card.
The risk is human error. If the operator forgets to switch the type when changing molds, the temperature reading is wrong. The error may be small at low temperatures and large at high temperatures. The parts may fail inspection before the operator notices. Some controllers have automatic detection that reads the thermocouple type from a chip in the connector. This eliminates the risk. But not all controllers have this feature.
For shops with mixed molds, J/K switching is a valuable feature. It saves money and time. But it requires discipline. The operator must verify the type setting before starting production. A checklist helps. Training helps. The controller itself may provide a warning if the temperature response does not match the expected type.
