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Instrumentation & Control
Control Panels and HMI
Control panels and HMI cover the operator interfaces outside the main driller's chair. That means touch-screen operator panels, joystick consoles, local control stations beside machines, and pressurised or flameproof panels for hazardous zones. A human-machine interface (HMI) panel is configured hardware, so a used one needs the same part number, firmware and display project as the panel it replaces.
Function on the rig
An HMI shows machine status and alarms and sends operator commands to a PLC or drive. You find them in the driller's cabin, mud pump room, crane cab, ballast control room and on local control stations beside the top drive, iron roughneck and pipe handler. Local stations let a crew run a machine from beside it during maintenance or when the cabin is down, and they normally carry a hardwired emergency stop.
Configurations by protection method
| Method | How it protects | Typical use |
|---|---|---|
| Ex d flameproof | Contains an internal explosion and cools gas through flame paths | Small local stations and push-button boxes |
| Ex e with Ex d components | Prevents sparks and hot spots in the enclosure | Terminal boxes and control stations |
| Ex p pressurised | Keeps clean air at overpressure inside the enclosure | Large panels with screens and PCs |
| Ex i intrinsically safe | Limits circuit energy below ignition level | Displays and keypads with IS barriers |
| Safe area | No Ex protection | Cabins and control rooms outside zones |
IEC 60079-2 defines three pressurisation types. Types px and py give equipment protection level Gb, suitable for Zone 1, and type pz gives Gc, suitable for Zone 2.
Key specifications
| Parameter | Why it matters | Typical classes or units |
|---|---|---|
| Ex marking | Sets the zone, gas group and temperature class | Ex db IIB T4 Gb, Ex pxb IIC T4 Gb |
| Ingress protection | Wash-down and weather on deck | IP56 to IP66 |
| Protocol | Must match the controller | Profinet, EtherNet/IP, Modbus TCP |
| Supply | Power and, for Ex p, instrument air | 24 V DC, 230 V AC, air pressure in bar or psi |
| Screen | Readability in daylight and with gloves | Size in inches, resistive or capacitive touch |
Standards and certification
- IEC 60079-14 sets how the panel is selected and installed for its zone, including cable glands and earthing.
- IEC 60079-17 sets in-service inspection. It defines visual, close and detailed inspection grades, with a detailed inspection opening the enclosure.
- IEC 60079-19 covers repair and overhaul. A repaired Ex panel should come with the repair facility's report and a marking that shows it was repaired.
- ATEX or IECEx certification must cover the panel as built. An added cable entry, a replaced window or a non-approved component can void it.
- On classed units, operator stations that form part of a classed control system need class type approval.
Failure modes and inspection
- Flame path corrosion or damage on Ex d enclosures. Measure gaps against the certificate drawing, and never paint or gasket a flame path unless the certificate allows it.
- Gasket hardening and gland failure, which let water in.
- Purge controller faults, a blocked purge outlet, or wrong timer and pressure switch settings.
- Joystick deadman switches, potentiometers and rubber boots.
- Backlight dimming, dead pixels and failed touch layers.
- Emergency stop contacts that stick after years without operation.
A close inspection to IEC 60079-17 plus a powered function test of every button, screen and stop covers most risks.
Documentation
Ask for the Ex certificate and its schedule, the manufacturer's declaration or IECEx certificate of conformity, any repair reports to IEC 60079-19, the display project file, firmware and runtime licence details, and for Ex p panels the purge controller settings.
Integration and compatibility
The display project must match your PLC program's tag addresses. A panel one firmware release newer may refuse an older project, or need conversion in the engineering software. Check the protocol card, the cable entries against your glands, and for Ex p panels the instrument air quality and the shutdown action on purge loss.
Refurbishment and when used makes sense
A like-for-like spare for a console that is out of production is the usual case for a used HMI. Unused surplus in original packaging suits critical stations, though gaskets and electrolytic capacitors age on the shelf. Refurbishment of an Ex panel belongs with a facility competent under IEC 60079-19. For a new console layout, new panels are usually simpler than adapting old ones.
Related equipment
Complete cabin packages are under drilling control systems, and the controllers behind these screens under automation systems. Naventr can arrange an inspection of a panel on request.
FAQ
Frequently asked questions
Does a used HMI panel need recertifying for a hazardous area?
No, if it still matches its certificate and nobody has modified it. It still needs an initial inspection under IEC 60079-14 before use. Any repair or modification to the Ex enclosure belongs with a facility working to IEC 60079-19.
Will a used operator panel work with my rig's PLC?
Only if the model, firmware, protocol and display project match your installation. Ask the Seller for the part number, revision and project backup, then compare them with your installed panel and the OEM's compatibility list.
What is the difference between Ex px, py and pz pressurisation?
They differ in the protection level they give. Types px and py reach equipment protection level Gb for Zone 1, and type pz reaches Gc for Zone 2. Px is the type used for enclosures holding ignition-capable equipment such as PCs and screens in Zone 1.
What does an IEC 60079-17 detailed inspection check on a panel?
A detailed inspection opens the enclosure and checks what a visual or close inspection cannot. That includes flame path condition and gaps, terminal tightness, internal corrosion, and that internal parts match the certificate. Isolate the circuit first.
Can I drill an extra cable entry in a flameproof panel?
No, not on site. A new entry in an Ex d enclosure changes the certified design and voids the certificate. Have the manufacturer or a repair facility working to IEC 60079-19 do it. Otherwise use a spare entry that already exists, swapping its certified blanking plug for a certified gland.
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