Before You Start Wiring
This page describes connections involving 120V or 240V AC mains voltage. If you are not comfortable working with mains voltage, have a licensed electrician review your work before powering the circuit. Always build with the enclosure unplugged. Use appropriately rated wire (14 AWG minimum for 15-amp circuits in North America), proper insulated connectors, and a grounded metal or reinforced plastic enclosure.
Power Supply Connections
The PID controller requires a 12V DC supply.
Power Supply Connections
The PID controller requires a 12V DC supply. Mount a small switching power supply (5W or more) inside the enclosure. Connect the AC input of the power supply to the incoming AC line and neutral conductors via a terminal block. Connect the DC output
PID to SSR Signal Wiring
The PID output terminals send a low-voltage DC signal to the SSR control input
PID to SSR Signal Wiring
The PID output terminals send a low-voltage DC signal to the SSR control input to switch the relay on and off. Connect PID output terminal labeled OUT1 or AL1 to the positive control input terminal on the SSR. Connect the PID output ground (sometimes a
SSR to AC Load Wiring
The SSR switches the hot (live) AC conductor only.
SSR to AC Load Wiring
The SSR switches the hot (live) AC conductor only. Connect the incoming AC hot wire from your power cord to the SSR load input terminal (marked L or IN on the SSR body). Connect the SSR load output terminal to the hot terminal of the AC outlet mounted on
Temperature Probe Wiring
The DS18B20 waterproof probe has three wires: red (power), black (ground), and
Temperature Probe Wiring
The DS18B20 waterproof probe has three wires: red (power), black (ground), and yellow or white (data). Connect red to the PID sensor supply terminal (usually +5V or the positive sensor terminal). Connect black to ground. Connect the data wire to the
Final Wiring Inspection
All AC conductors are insulated with no bare metal visible
All low-voltage signal wires are routed away from AC conductors
The SSR is mounted flush to the enclosure or a metal heatsink
Every wire termination uses a proper crimp connector, not bare twisted wire
Ground wire is connected at power cord, outlet, and enclosure chassis
All wire entries into the enclosure use strain relief grommets
Enclosure lid closes securely with no wires pinched at the edge
Label Your Wires Use small adhesive labels or heat-shrink labels on every wire before closing the enclosure. Label each wire with its function: AC HOT IN, AC HOT TO OUTLET, AC NEUTRAL, GROUND, PID OUT+, PID OUT-, PROBE DATA, PROBE VCC, PROBE GND. This takes five minutes and saves enormous time if you ever need to diagnose or modify the circuit later.