CNC Section CCTV Specification: Stack Light, Door and Operator Views for a 12-Machine Bay (India)
A camera outside a CNC looks through a scratched, coolant-filmed polycarbonate guard window, and from the aisle end it sees those windows edge-on, so what it reads on a CNC is the stack light, the door and the operator, not the spindle. Planned for those signals, the worked bay below (two rows of six, checked 15 Oct 2026) needs 9 cameras for 12 machines: six across-aisle cameras on the doors at 125 px/m (IEC 62676-4:2014 Recognise), two aisle-end cameras for stack lights and people, and one over the first-piece table.
Last checked: 15 Oct 2026. The bay layout is a worked assumption; densities, lens angles and bitrates are sourced.
Verified against
- IEC 62676-4:2014 pixel densities (12.5 / 25 / 62.5 / 125 / 250 / 1,000 px/m), quoted in the foreword of IEC 62676-4:2025, edition 2.0, published 9 Oct 2025 (public preview, STN EN IEC 62676-4:2026; IEC webstore).
- United Grinding, Viewing windows – regular maintenance can prevent accidents (27 Jul 2023).
- CP Plus datasheets CP-UNC-DA41L3C-Q and CP-UNC-TA41L6C-Q, both "Published Date 19-08-2025", re-read 15 Oct 2026.
- Prama PT-NC346P1-WNRAM(D2) product page; Matrix SATATYA CIDR50FL28CWP P2 datasheet (vendor link from matrixcomsec.com).
- Hikvision, H.264(5) & H.264(5)+ Recommended Bit Rate at General Resolutions (archive copy; original returns 403).
- Checked 15 Oct 2026. Nobody tested a camera for this page.
Seeing through the enclosure window
Every CNC view starts with the same obstacle: a guard window between the camera and the work. Four things on a working machine stop a camera from reading what happens behind it.
- The window itself ages. United Grinding (27 Jul 2023) writes that polycarbonate "is sensitive to coolants" that "may cause the window to become brittle", that ISO 16089 recommends replacement every two years, and that "cracks, scratches, or visible coolant infiltration" call for immediate replacement. Embrittlement is "usually invisible"; the scratches and coolant film are what blind a camera.
- Coolant mist reaches the lens. A camera in spray range films over. Mount it across the aisle, above head height, and put lens cleaning on the weekly checklist.
- Lights bounce off the glass. Tube lights and the camera's own IR reflect from the window. Angle the door camera down rather than square-on, and switch IR off where aisle lights stay on.
- The cabinet lamp outshines the aisle. The machine's work lamp makes the window brighter than its surroundings. Cameras with only DWDR clip one or the other; both CP Plus sheets list only DWDR, while the Prama page lists 120 dB WDR.
How the view angle trades these off (planning assumptions drawn from the points above, not a test):
| Camera position | Window reflections | Into the window | Stack-light legibility |
|---|---|---|---|
| Square-on to the door, across the aisle | Worst: tube lights and IR bounce straight back | Door, lamp, operator; the tool only through a clean window | Good when the light sits on top of the machine |
| Across the aisle, 4.5 m high, angled down | Reduced | Door, lamp, operator | Good |
| Aisle end, looking down the row | Not a factor | Nothing: the windows are edge-on | Every light in the row |
So the plan is built on the door, the lamp and the operator, not on the tool. Extra pixels on the door view buy margin against a dirty window; they do not let a camera read a cut.
Machine states a camera can read
| State | Where it is read from | Level to plan for | px/m on target | Notes |
|---|---|---|---|---|
| Stack light colour | Aisle-end camera | Observe | 62.5 | Colours are set by each machine builder; record each machine's scheme at commissioning |
| Door open / closed | Across-aisle door camera | Recognise | 125 | Planned higher than the state needs, to survive scratches and film |
| Operator at the machine | Door camera or aisle camera | Observe | 62.5 | The aisle view also shows the setter walking the row |
| First-piece table occupied, inspector present | Camera over the table | Recognise or better | 125+ | The queue this view watches is priced in first-piece approval waiting |
| Spindle cutting, parts made | Not from these views | — | — | A spindle warming up, coolant running with no cut or a bar feeder cycling all move |
The px/m values are IEC 62676-4:2014 levels; mapping machine states to them is our assumption. How the levels are defined, and how to turn them into a lens, is in the DORI explainer; the lens and DORI calculator runs the numbers for your bay. Video shows changes of state; it does not count parts on a CNC from these positions.
The 9-camera layout for 12 machines
Layout assumption: two rows of six VMCs or CNC lathes facing a 4 m aisle, 4 m machine pitch (24 m rows), roof truss above 6 m, cameras on columns or a bracket above the opposite row at 4.5 m, one first-piece table at the end of the bay.
| Position (count) | Model, from its datasheet | Pixels, printed HFOV | Mount and slant to target (assumed) | Covers (m) | px/m | What it reads |
|---|---|---|---|---|---|---|
| Across the aisle, one per pair of machines (6) | CP Plus CP-UNC-DA41L3C-Q dome, 3.6 mm, 4 MP | 2688, 78° | 4.5 m high, 6.5 m back, 7.2 m slant | 11.7 | 229 centre, ~200 at the outer door | Doors, lamp, operator (Recognise) |
| Aisle end, one from each end (2) | CP Plus CP-UNC-TA41L6C-Q bullet, 6 mm, 4 MP | 2688, 49° | 4.5 m high, far machine 24.2 m slant | 22.1 | 122 at far end, 237 at mid-row | Stack lights, people (Observe; Recognise from mid-row) |
| Over the first-piece table (1) | CP Plus CP-UNC-DA41L3C-Q dome | 2688, 78° | 3 m high, 2.5 m back, 3.3 m slant | 5.3 | 508 | Part on the table, inspector (Recognise and above) |
A door camera at 7.2 m needs a lens no wider than 112° to hold 125 px/m and at least 58° to cover two machines at 4 m pitch; the 78° dome sits inside that window. CP Plus prints a Recognise distance of 15.2 m for this dome, while the geometry gives 13.3 m, so plan from the printed angle rather than the vendor's DORI line.
Swaps from the dataset: a Matrix SATATYA CIDR50FL28CWP P2 (5 MP, 2592 px, 107.6°, IK10) in the door position gives 131 px/m, Recognise with no margin. A Prama PT-NC346P1-WNRAM(D2) (4 MP, 2.7–13.5 mm, 96.7°–29.7°, IK10, 120 dB WDR) can be zoomed to frame exactly two doors.
Scaling to N machines (rule of thumb, assumption): door cameras ceil(N ÷ 2), plus 2 per aisle up to about 24 m long, plus 1 per inspection table. For N = 12 in one aisle: 6 + 2 + 1 = 9.
The minimum is 2. Two aisle-end cameras see every stack light and every operator in a 24 m row. They do not see into any machine: "running" then rests entirely on the stack light.
Mounting, impact and light near the machines
| Item | Spec for a CNC bay | Source |
|---|---|---|
| Ingress | IP67 printed for all three example models; cameras sit outside the enclosure, never inside it | CP Plus datasheets; Prama page; test meanings in the IP/IK guide |
| Impact | IK10 where a crane hook, bar stock or a forklift mast can reach | CP Plus DA41L3C-Q and TA41L6C-Q list no IK rating; Prama PT-NC346P1-WNRAM(D2) and Matrix CIDR50FL28CWP P2 list IK10 |
| Low light and IR | 0.03 [email protected] colour, 0 lux with IR on, IR 30 m (DA41L3C-Q); 0.001 [email protected] colour, IR 60 m (TA41L6C-Q) | CP Plus datasheets |
| Humidity | ≤95% RH, non-condensing (DA41L3C-Q) | CP Plus datasheet |
| Portrait (corridor) view down the aisle | CP Plus: "4MP only support 0°/180°" rotation; 2 MP and lower support 90° | CP Plus datasheets |
| Flicker | Cheap 50 Hz LED battens roll bands across the frame; fix it in shutter settings | Flicker guide |
Storage in one line: nine 4 MP cameras on H.265 come to 6.0 TB for 30 days at 15 fps and 11.9 TB at 25 fps by the Hikvision bitrate sheet, before the 20–30% it adds "if the real environment is more complex" (coolant spray and chips qualify). Size the disk from the NVR days table.
When to call the installer / what to ask the vendor
Ask for the HFOV at the focal length you will set, true WDR in dB, the IK rating of the exact model, and whether the 4 MP stream supports corridor mode. At handover, check px/m on the outermost door of each pair, confirm every stack light is visible from an aisle camera, and write down each machine's stack-light colours.
Mama reads a factory's existing cameras over RTSP/ONVIF and tells the owner, in plain language, which machines stood idle and for how long. A CNC bay specified like this gives it the sightlines to do that (askthemama.com). Tell workers what the cameras record (DPDP notice). Leave an email or phone in the form below.
FAQ
Can a CCTV camera see the spindle inside a CNC? Not from outside the enclosure. The guard window scratches, takes on coolant film and reflects the shop lights, so a camera outside the enclosure reads the door, the work lamp, the stack light and the operator, not the cut.
How many cameras do I need for 12 CNC machines? For two rows of six on one aisle, 9: one per pair of machines across the aisle, one at each end of the aisle and one over the first-piece table. Two aisle cameras alone show stack lights and people only.
Where should a camera be mounted to monitor a CNC machine? Outside the enclosure, across the aisle, about 4.5 m high and angled down at the door window, out of coolant spray. Never on the guard or inside the work area.
Can a camera tell a running CNC from an idle one? From the stack light, the door and the operator read together. It cannot count parts from these views, and a spindle warming up or coolant running with no cut can look busy.