Power Dissipation Considerations

The power dissipated within the enclosure generates heat. The enclosure supplier uses power dissipation figures to determine the air flow requirements needed to maintain the allowable heat rise. As the internal heat rise increases, the allowable external ambient temperature decreases.

The power dissipation in an enclosure is dependent on the power requirements of the enclosed equipment, including the:

Power required to operate devices in the enclosure
Field power dissipation within the cabinet
Power dissipated by the power supplies located in the enclosure

The following table lists maximum power dissipation for each DeltaV component. To determine total power dissipation in an enclosure, sum the power requirements of all components to be mounted within the enclosure.

Note

The power dissipation for each DC-powered discrete and analog device includes the loss of a power supply which is 75% efficient. If the power supply is not included in the enclosure or a supply with a different efficiency is used, adjust the dissipation accordingly.

Product Type	Power
P-series controllers (PK)	7.5 W simplex; 15 W redundant
I/O Subsystem
AI, 8-Channel, 4-20 mA	10.1 W
AI, 8-Channel, 4-20 mA, HART	10.1 W
AI, 8-Channel, 1-5 VDC	10.1 W
AO, 8-Channel, 4-20 mA	11.9 W
AO, 8-Channel, 4-20 mA, HART	11.9 W
AS-Interface	9.6 W
DeviceNet	11.4 W
DI, 8-Channel, 24 VDC, Isolated	3.6 W
DI, 8-Channel, 24 VDC, Dry Contact	2.9 W
DI, 8-Channel, 120 VAC, Isolated	3.4 W
DI, 8-Channel, 120 VAC, Dry Contact	3.4 W
DI, 8-Channel, 230 VAC, Isolated	3.6 W
DI, 8-Channel, 230 VAC, Dry Contact	3.6 W
DI, 32-Channel, 24 VDC, Dry Contact	5.7 W
DO, 8-Channel, 120/230 VAC, Isolated	6.1 W
DO, 8-Channel, 120/230 VAC, High Side	6.1 W
DO, 8-Channel, 24 VDC, Isolated	4.9 W
DO, 8-Channel, 24 VDC, High Side	3.7 W + load dependent power dissipation (25 W maximum at 24 V)⁽¹⁾
DO, 32-Channel, 24 VDC, High-Side	3.0 W + load dependent power dissipation (27 W maximum at 24 V)⁽²⁾
Fieldbus H1 card	10.2 W
Multifunction	8.2 W
Profibus DP	10.1 W
RTD, ohms	2.7 W
Sequence of Events	3.5 W
Serial Card, 2 Ports, RS232/RS485	5.1 W
Thermocouple, mV	5.9 W
Series 2 I/O Cards
Series 2 AI, 4-20 mA with HART Simplex/ Redundant	8.4 W 9.1 W (per card)
Series 2 AI, 16-channel, 4-20 mA HART (Simplex)	12.7 W
Series 2 AO, 4-20 mA with HART Simplex/ Redundant	10.2 W 10.2 W (per card)
Series 2 AS-Interface (Simplex)	9.6 W
Series 2 DeviceNet (Simplex)	11.4 W
Series 2 DI, 8-Channel, 24 VDC Dry Contact Simplex/ Redundant	3.7 W (per card)
Series 2 DI, 32-Channel, 24 VDC Dry Contact (Simplex)	5.7 W
Series 2 DO, 8-Channel, 24 VDC, High-Side Simplex/ Redundant	3.7 W (per card)
Series 2 DO, 32-Channel, 24 VDC, High-Side (Simplex)	3.0 W + load dependent power dissipation (27 W maximum at 24 V)⁽³⁾
Series 2 H1 Simplex/ Redundant	6.1 W (per card)
Series 2 Isolated Input (Simplex)	5.9 W
Series 2 Profibus (Simplex)	10.1 W
Series 2 RTD, ohms (Simplex)	2.7 W
Series 2 Thermocouple (Simplex)	3.5 W
Series 2 Serial Simplex/ Redundant	5.1 W (per card)
Power Supplies
System Power Supply (AC/DC)	4.4 W
P-Series Power Module	3.25 W
DeltaV SIS Components
Simplex Logic Solver	16.0 W
Redundant Logic Solvers	24.0 W
SISNet Repeaters	9.6 W (per Repeater)
Auxiliary Relay Modules, Energize to Actuate and De-Energize to Actuate, 24 VDC	4.65 W
Auxiliary Relay Diode Module	2.25 W
Miscellaneous Components
Fieldbus H1 carrier	5.2 W⁽⁴⁾
Media Converter	5.1 W
Single Port Fiber Switch	8.2 W
Four Port Fiber Switch	8.4 W

⁽¹⁾ Power dissipation in this card is based on a full load of 3 A at 24 V. Actual dissipation is determined by the following equation: Supply Voltage x Actual Load Current (8 channels) x [(1/Power Supply Efficiency) - 1] A typical value for eight channels driving a 24 V solenoid is 16.4 W.

⁽²⁾ Power dissipation in this card is based on a full load of 3.2 A at 24 V. Actual dissipation is determined by the following equation: Supply Voltage x Actual Load Current (32 channels) x [(1/Power Supply Efficiency) - 1]

⁽³⁾ Power dissipation in this card is based on a full load of 3.2 A at 24 V. Actual dissipation is determined by the following equation: Supply Voltage x Actual Load Current (32 channels) x [(1/Power Supply Efficiency) - 1]

⁽⁴⁾ Does not include I/O card dissipation or 2.2 W power supply dissipation. (Assumes power supply is not in the same enclosure as the H1 carrier.)