Watlow PM LEGACY ™ Limit controller

Installation and wiring

（1） Installation process

Panel perforation: The PM3 controller needs to be perforated according to the size on page 6 of the document, and the PM6 controller needs to be perforated according to the size on page 7 to ensure that the controller can be smoothly embedded into the panel.

Component disassembly: Remove the green terminal connector and installation ring assembly to avoid damaging the components during installation.

Controller embedding: Insert the controller into the opening from the front of the panel. Taking PM6 as an example, ensure that the installation direction is correct.

Installation ring fixation: Move the installation ring base plane forward, with the screw opening facing the side, and slide it over the back of the controller; Slide the installation bracket over the controller again, aligning the screws with the base, and gently push until the hook clicks into the slot of the housing; Finally, use a Phillips screwdriver to tighten the two # 6-19 x 1.5 inch screws with a torque of 3-4 inch pounds, ensuring that the device is flush with the panel.

Terminal reset: Reinstall the terminal connector to its original position to complete the installation.

Installation spacing requirements: 1/32 DIN (PM3) recommends a panel spacing of 44.96-45.47mm (1.77-1.79 inches), a minimum panel thickness of 21.6mm (0.85 inches), and a panel thickness range of 1.53-9.52mm (0.060-0.375 inches); 1/16 DIN (PM6) recommends a panel spacing of 44.96-45.47mm (1.77-1.79 inches), with other thickness requirements consistent with PM3 to ensure heat dissipation and operational space.

（2） Wiring specifications

Power wiring

Low power model (PM6 [L, M] [3,4} _J-A_G _): supports 12-40Vdc, 20-28Vac (50/60Hz), maximum power consumption of 10VA (PM6), power terminals are 98 (ac/dc+) and 99 (ac/dc -) of Slot C, pay attention to voltage polarity, and comply with NEC or local electrical standards to avoid overvoltage or reverse connection damage to equipment.

High power model (PM6 [L, M] [1,2} _J-A_G _): Supports 85-264Vac, 100-240Vac (Semi Sig F47 standard, 50/60Hz), maximum power consumption of 10VA (PM6), power terminals are also 98 and 99 of Slot C, and suitable fuses are required to prevent overload.

Input wiring

Analog input (Slot A): The terminals of universal sensor input 1 include T1, S1, R1 (thermocouple+ RTD S1、 Potentiometer sliding end, S3 (thermocouple - RTD S3、 Current - etc.), wiring needs to be done according to the sensor type, for example, thermocouples need to distinguish between positive and negative poles, and RTD 3-wire system needs to connect S1 to R1/R2; The process input (voltage/current/millivolts) should be wired according to the terminal identification (such as voltage+connected to S1, voltage - connected to S3) to ensure signal integrity.

Digital input (Slot C): The terminals of digital input 5/6 are D5, D6 (signal), and B5 (common terminal). The voltage input needs to be connected to a DC power supply (such as 24Vdc), and the dry contact input needs to be directly connected to an external contact. When wiring, attention should be paid to isolating from other circuits to prevent interference.

Output wiring

Mechanical relay/SSR (Slot A/B): The terminals of Form C relay are L_ (normally open), K0 (common), and J2 (normally closed), while the terminals of Form A relay are L_ (normally open) and K0 (common). The wiring should be based on the load type (AC/DC), and the load current should not exceed the rated value; SSR only supports AC loads, please pay attention to the phase and voltage range.

Switch DC/collector open circuit (Slot A/B): The terminals are W_ (dc+), X_ (dc -, collector open circuit), and Y1 (common), and an external power supply is required to drive the load (such as a solid-state relay) to ensure that the power supply voltage matches the load and avoid short circuits.

Universal process output (Slot B): The voltage output terminals are F3 (-) and G3 (+), and the current output terminals are F3 (-) and H3 (+). The wiring should be based on the configured output type, and the load impedance should meet the requirements (minimum voltage output of 1k Ω, maximum current output of 800 Ω).

Communication wiring

EIA-485 (Slot C/B): The terminals of Standard Bus/Modbus RTU are CC (common) CA（T-/R-）、CB（T+/R+）， Twisted pair cables (such as Cat 5) should be used, with a Daisy chain network topology, a maximum of 16 nodes (Standard Bus) or 247 nodes (Modbus), a maximum transmission distance of 1200 meters, and a 120 Ω terminal resistor connected to the end device.

EtherNet/IP ™/ Modbus TCP (Slot B): The RJ-45 interface is wired according to the T568B standard, with pins E1 (white orange, transmit+), E2 (orange, transmit -), E3 (white green, receive+), E6 (green, receive -). The other pins are not used and need to be connected to a 10/100Mbps Ethernet switch.

DeviceNet ™ (Slot B): The terminals are V+(power+), CH (CAN_S), SH (shielded), CL (CAN_L), V - (power -), and shielded twisted pair cables are required. The node address is 0-63, the baud rate is 125/250/500kbps, and the shielding layer needs to be single ended grounded.