Conformal Coating
Conformal coatings are specially formulated thin film materials that are applied directly to circuit boards or circuit card assemblies (CCAs). These films provide environmental protection for components and circuitry. The thin film materials used for conformal coating are normally applied using a process of dipping or spraying the CCA with a liquid or resinous material. As the material dries, it forms a resilient coating that can protect against moisture, mold, dust, corrosion and other environmental stresses.
Condensation
Condensation can occur when the outside air temperature increases at a faster rate than the electronics. If the temperature of the electronics reaches the dew point, condensation will occur. The higher the relative humidity, the closer the dew point is to the current temperature. This scenario could occur if a product was stored in a vehicle over night. When the outside air heats up, there is a potential for the electronics to reach their dew point. This occurs on the aluminum enclosures due to the thermal capacitance of aluminum. Once condensation forms on the enclosure, there is a higher probability of shorts on the CCA.
The application of a conformal coating prevents condensation from making contact with traces, vias, and integrated circuits (IC’s) on CCAs. This prevents the formation of corrosion and shorting on these components after exposure to condensation. Connectors do not benefit from the conformal coating, so corrosion could still occur at the connectors. The conformal coating is intended to extend the life of the product by protecting the traces, vias, and fine pitch IC’s, but it does not eliminate all environmental risk associated with the connectors.
Figure 1. Conformal coated CCA shows no corrosion after exposure to condensation
Figure 2. Corrosion has occurred on the uncoated CCA after exposure to condensation
To minimize corrosion on connectors, National Instruments recommends the following tips:
• Mount the system in horizontal orientation, with the I/O connectors facing forward. This allows condensation to run off the CCA’s and not to pool up in the connectors.
• Do not create any drip lines with cabling. All cables should be routed down, so any condensation that occurs on the cable will not be channeled into the connector or product.
• Ensure the electronics are not in other drip lines
• To help protect backplane connectors, use a filler module or dust cover in any empty slot.
National Instruments uses ELPEGUARD SL 1307 FLZ to provide environmental protection for certain products. This modified acrylic resin is manufactured by Lackwerke Peters (see manufacturers datasheet for technical specifications).
ELPEGUARD SL 1307 FLZ has been approved as a conformal coating by UL under QMJU2.E80315. Additionally, National Instruments has tested the conformal coated products for the following environmental specification.
Environmental
Operating humidity
(IEC 60068-2-30 Test Db)……………….80 to 100% RH, condensing
Additional test reports and datasheets on the coating material, ELPEGUARD SL 1307 FLZ, are available in the Developer Zone. These tests were not performed on National Instruments products, they are provided to reference the properties of the conformal coating.
The table below shows the C Series modules and CompactRIO and Single-Board RIO systems available with conformal coating. If the particular system or I/O module you need for you application is not available please contact National Instruments.
Figure 3. CompactRIO Packaged and Single-Board RIO Board-Level Systems
Model Number | Description |
CompactRIO Controllers and Chassis | |
cRIO-9038 | 8-slot, Intel Atom & Kintex-7 160T Integrated Real-Time Controller and Chassis |
cRIO-9068 | 8-Slot, Zynq-7020 Integrated Real-Time Controller and Chassis |
cRIO-9065 | 4-Slot, Zynq-7020 Integrated Real-Time Controller and Chassis |
cRIO-9014 CC | Real-Time Controller with 400 MHz processor, 2 GB Storage |
cRIO-9023 CC | Real-Time Controller with 533 MHz processor, 2 GB Storage |
cRIO-9025 CC | Real-Time Controller with 800 MHz processor, 4 GB Storage |
cRIO 9113 CC | 4-Slot, Virtex-5 LX50 CompactRIO Reconfigurable Chassis |
cRIO-9114 CC | 8-Slot, Virtex-5 LX85 CompactRIO Reconfigurable Chassis |
cRIO-9118 | 8-Slot, Virtex-5 LX110 CompactRIO Reconfigurable Chassis |
Single-Board RIO Devices | |
Contact your NI Account Manager to discuss Conformal Coating on Single-Board RIO | |
C Series Analog Input Modules | |
NI 9203 CC | 8-Channel +/-20mA, 16-bit Current Input Module, Screw |
NI 9205 CC | 32-Channel +/-10V, 16-Bit, 250 kS/s Voltage Input Module, DSUB |
NI 9207 CC | 16-Channel (8 Voltage and 8 Current), +/-10V and +/-21.5mA, 500 S/s, 24-bit Analog Input Module, DSUB |
NI 9208 CC | 16-Channel +/-21.5mA, 500 S/s, 24-bit Current Input Module, DSUB |
NI 9213 CC | 16-Channel Thermocouple Module, Screw |
NI 9219 CC | 4-Channel, TC, RTD, Resistance, Bridge, Voltage, Current, 100 S/s/ch, 24-bit Universal Input Module, Spring |
NI 9221 CC | 8-Channel, +/-60V, 800 kS/s, 12-bit Voltage Input Module, DSUB |
NI 9225CC | 3-Channel, 300 Vrms Voltage Input Module,Screw |
NI 9227 CC | 4-Channel, 5 Arms, 50 kS/s/ch, 24-bit Current Input Module, Screw |
NI 9230 CC | 3-Channel, +/-30V, 12.8 kS/s/ch, IEPE. Voltage Input Module, Screw |
NI 9232 CC | 3-Channel, +/-30V, 102.4 kS/s/ch, IEPE, Voltage Input Module, Screw |
NI 9234 CC | 4-Channel, +/-5V, 51.2 kS/s/ch, 24-bit, IEPE, Voltage Input Module, BNC |
NI 9237 CC | 4-Channel, Bridge-based, 50 kS/s/ch, 24-bit, Voltage Input Module, DSUB |
NI 9239 CC | 4-Channel, +/-10V, 50 kS/s/ch, 24-bit, Ch-Ch Iso, Voltage Input Module, Screw |
C Series Analog Output Modules | |
NI 9264 CC | 16-Channel +/- 10V, 25 kS/s/ch, 16-Bit, Voltage Output Module, DSUB |
NI 9265 CC | 4-Channel, 100 kS/s, 16-Bit, 0 to 20 mA Current Output Module, Screw |
NI 9269 CC | 4-Channel, +/- 10V, 100 kS/s/ch, 16-bit, Ch-Ch Iso, Voltage Output Module, Screw |
C Series Digital Input Modules | |
NI 9401 CC | 8-Channel, 5V/TTL, 100 ns, Sinking/Sourcing, Bidirectional Digital I/O Module, DSUB |
NI 9403 CC | 32-Channel, 5V/TTL 7 us, Sinking/Sourcing, Bidirectional Digital I/O Module, DSUB |
NI 9411 CC | 6-Channel, 500 ns, +/- 5 to 24V Digital Input Module |
NI 9421 CC | 8-Channel, 24 V, 100 us, Sinking, Digital Input Module, DSUB |
NI 9425 CC | 32-Channel, 24 V, 7 us, Sinking Digital Input Module, DSUB |
NI 9426 CC | 32-Channel, 24 V, 7 us, Sourcing Digital Input Module, DSUB |
NI 9437 CC | 8-Channel, 24 V to 250VDC, 1 us, Sinking Digital Input Module, Screw |
C Series Digital Output Modules | |
NI 9475 CC | 8-Channel, 60 V, 1 us, Sourcing Digital Output Module, DSUB |
NI 9476 CC | 32-Channel, 24 V, 500 us, Sourcing Digital Output Module, DSUB |
NI 9477 CC | 32-Channel 5 to 60 V, 8 us, Sinking Digital Output Module, DSUB |
NI 9478 CC | 16-Channel, 48 V, 50 us, Sinking Digital Output Module, DSUB |
NI 9485 CC | 8-Channel, 60VDC/30Vrms, 750 mA, SSR Relay Output Module, Screw |
C Series Communications Modules | |
NI 9853 CC | 2 Port, High-Speed Controller Area Network (CAN) Module |
NI 9870 CC | 4-port, RS232 Serial Interface Module, RJ50 |
NI 9871 CC | 4-Port, RS485/RS422 Serial Interface Module, RJ50 |
C Series Communications Modules | |
NI 9802 CC | Secure Digital Storage Module |
C Series Timing & Synchronization Modules | |
NI 9469 CC | Signal Based Synchronization Module, RJ45 |