Assume the system consists of the following components:
| Quantity | Product Type | Power Dissipation |
|---|---|---|
| 1 | Controller (PK) | 7.5 W |
| 1 | AI, 8-channel, 4-20 mA, HART | 10.1 W |
| 1 | AO, 8-channel, 4-20 mA | 11.9 W |
| 1 | DI, 8-channel, 24 VDC, isolated | 3.6 W |
| 1 | DO, 8-channel, 24 VDC, high side (driving 8 solenoids) | 3.7 W + 16.4 W |
| 2 | DO, 8-channel, 120/230 VAC, isolated | 12.2 W |
| 2 | DI, 8-channel, 120 VAC, isolated | 6.8 W |
| 1 | PK power module | 3.25 W |
| Total power | 79.85 W |
Assume ambient temperature is 35°C. The DeltaV components are rated for an ambient temperature of 60°C. Therefore, the enclosure design temperature rise must be less than 60 - 35 = 25°C with 79.85 W of heat dissipation within it.
If the surface area of the enclosure is insufficient to dissipate the heat, you can use cooling options such as fans or blowers to improve heat dissipation.
The actual temperature rise varies with layout, enclosure location, and other factors. If the application is critical or if the exact conditions are undetermined, follow your standard corporate/plant safety standards. Cabinet manufacturers recommend a safety margin of 25%.