1. Overall PLC Control Panel Layout — Shop Photos (zoned top to bottom)
A standard PLC panel is divided from top to bottom into4 zones: top heat dissipation zone (fan + thermostat), upper zone (PLC CPU + I/O modules + switching power supply), middle zone (interposing relay bank + terminal blocks), lower zone (contactors + breakers + incoming/outgoing feeders). The photos showclear component zoning, power and control wiring run in separate ducts, and the PLC CPU mounted center-upper for easy access.
2. In-Cabinet Wiring Practice — Shop Photos (power and control separated + wire duct standards)
Wiring is the core of assembly workmanship:spacing between the power circuit duct and the control circuit duct ≥200mm, and analog signal cables run in their own shielded conduit. The photos show:
- Main wire duct: 60mm wide × 35mm high, carries contactor coil and power wiring, with removable duct cover.
- Control wire duct: 40mm wide × 25mm high, carries PLC I/O signal wiring, fill ratio inside the duct ≤70%.
- Analog wiring: run separately in shielded corrugated conduit, crossing power cables only at right angles.
- Wire markers: heat-shrink printed, legible, with matching numbers at both ends of every wire.
3. HMI Installation — Shop Photos (panel cutout and wiring)
The touchscreen is mounted on thecabinet door panel, with the cutout sized to the HMI specification (e.g., Siemens KTP700 Basic requires a 193×146 mm cutout) and fitted with a waterproof gasket. Wiring behind the screen includes DC24V power, a PROFINET cable (to the PLC), and a USB port (for commissioning). In the photo, the touchscreen is fitted with astainless steel angled mounting bracket, giving a 15° operating angle for comfortable stand-up operation.
4. Component identification and nameplates, as built (every component has an ID)
ISO 9001:2015 requires every component tohave a unique identifier:
- Component nameplate: shows the component tag (e.g., -Q1 contactor, -K1 relay), model, and circuit number.
- Terminal identification: each terminal block is marked with its section number (e.g., X1:1–X1:20), matching the wiring diagram.
- Wire markers: both ends of every wire carry the same number, in a format such as 1L1-1 / I0.0-3.
- Cabinet nameplate: shows cabinet number, model, IP rating, weight, date of manufacture, and serial number.
5. Judging PLC panel workmanship from photos (5-point visual inspection standard)
① Neat wiring: wire bundles run straight and uncrossed in the duct, with evenly spaced ties (100–150 mm); ② Legible wire numbers: heat-shrink printed, ink does not rub off, orientation consistent; ③ Power and signal separation: main circuit and control circuit do not share a wire duct, spacing ≥200 mm; ④ Component layout: heat dissipation space above the PLC, relays arranged in a single row for easy servicing; ⑤ Proper grounding: separate PE bar, cabinet door grounding strap (braided copper) bonded to the cabinet body.
FAQ FAQ
What are the standard PLC control cabinet sizes?
Common cabinet widths are 600/800/1000/1200 mm, depths 300/400/600 mm, and heights 1800/2000/2200 mm. For a small PLC panel, choose 600×300×1800 mm; for a large one, 1000×400×2200 mm.
What material should a PLC control cabinet body be made of?
For an indoor control room, choosepowder-coated cold-rolled steel(1.5–2.0 mm thick); for outdoor or corrosive environments, choosestainless steel 304. The door should have a waterproof gasket, with an ingress protection (IP) rating of IP54 or higher.
Can the touchscreen be mounted on the cabinet door?
YesThis is the most common mounting method. Cut an opening in the door with a waterproof gasket, and run the wiring behind the screen through a cable gland in the door. Make sure to leave enough slack in the network and power cables when the door is open.
Does a PLC cabinet need air conditioning?
If the internal temperature stays at or below 55°C, no air conditioning is needed. If the CPU and power supply generate significant heat and the IP65 enclosure has poor heat dissipation, thencabinet micro air conditioner(300–800 W cooling capacity) is required, with the temperature set to 35°C.
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