Commercial White Good Solutions
Multichannel Temperature Sensors
Dishwashers for residential or commercial use implement a hot-temperature cleaning cycle. The reduction of water consumption, shorter cycle times, increased rack loads and sanitation of cookware are driving factors for increased dishwasher efficiency. The National Sanitization Foundation (NSF) requires a final rinse temperature of 150°F for residential dishwashers (NSF/ANSI 184) and 180°F for commercial dishwashers (NSF/ANSI 3), pulling in water from the hot water line.
A temperature sensor monitors the temperature of the dishwasher and if it is not maintained at a necessary temperature, the heating element turns on.
The EMC1812 provides ±1°C maximum error over the temperature range of interest. Programmable temperature limits provide a level of notification that may be used to trigger the heating element during the pre-wash and main wash cycles of the dishwasher to maintain a level temperature.
Other features of the EMC1812 are:
- Maximum error of ±1°C from –20°C to 105°C
- Automatic beta detection
- Anti-Parallel Diode (APD) functionality
- Resistance Error Correction (REC) up to 100 Ω
- Rate of change measurement
Thermocouple
Residential induction heating technology may be found in stand-alone cooktops, rice cookers, and hot water pots.
Induction-based cooking offers precise burner temperature control at much higher efficiencies than either gas or radiant heating elements. Insulated-Gate Bipolar Transistors (IGBTs) used in induction cooking applications dissipate a considerable amount of power, so to prevent the IGBT’s junction temperature from rising above its recommended specification value, large heat sinks are usually employed.
For smart induction cooktops, monitoring the induction heating surface temperature and the pot temperature provides better control. For this application, thermocouples can be embedded in both the pan and the induction cooktop surface and the main controller maintains optimum cooking temperature for the food compared to the surface temperature via connected wireless communication. Microchip’s MCP9600 plug-and-play thermocouple conditioning Integrated Circuit (IC) solution is ideal for such embedded applications.
The MCP9600 allows four external sources, standard on a residential cooktop, to be monitored to ±1°C max accuracy up to 125°C. The induction cooktop diagram is shown on Figure 9. The IGBT modules are mounted on the heat sink to ensure the IGBTs do not exceed their junction temperature. The temperature information is sent back to the system’s microcontroller in real time to mitigate over-temperature conditions.
Figure 9: Induction Cooktop Diagram
Temperature Switches
Home and small office equipment like document shredders have sheet capacities, often up to 18 sheets. The desire for continuous shredding with high capacities increases the heat in the shredder, which may cause it to seize. A cool-down period is then necessary before the shredder is operational. A temperature switch like the MCP9502 may be used to monitor the motor’s temperature and alert the user to thermal overload via an LED on the front panel.
The MCP9502 is available with factory preset temperature thresholds. This eliminates the need to program a thermal limit through software or use external components. A temperature above the limit will set a visual alert using an LED which identifies an increasing thermal condition.
Other features of the MCP9502 are:
- Push-pull output
- Factory presets from 5°C to 125°C
- Programmable hysteresis