Description

Yokogawa AEP9D Secondary Power Supply Bus Unit

The Yokogawa AEP9D-4, also cataloged as the AEP9D Secondary Power Supply Bus Unit, operates as a dedicated hardware component for distributing stable 24 VDC secondary power within CENTUM VP and CENTUM 3000 DCS cabinets. It receives dual-line inputs and delivers independent 9-output branches per line to connected terminal boards and sub-modules.

Hardware Specifications

Parameter	Specification
ModelBrand	AEP9D
Origin	Japan
Weight	1.8 kg nominal
Dimensions	160 mm x 130 mm x 45 mm
OperatingTemp	0 degC to 55 degC
PowerConsumption	Max input current: 20 A total; 10 A per port
InputPowerSupplyVoltage	24 VDC
WithstandingVoltage	500 V AC, 1 min
OutputPorts	9 per line, 3-pin MATE-N-LOK
StandardsConformance	CSA, CE Marking
InputTerminals	Line A/B: +24P, –24N; FG functional ground
OutputPinAssignments	Pin1: FG, Pin2: –24N, Pin3: +24P

Channel-to-Channel Isolation

The AEP9D ensures electrical isolation between Line A and Line B output channels, preventing cross-channel interference. Each output port maintains separation from adjacent ports to minimize ground loop currents and protect downstream control modules. This isolation supports stable 4-20 mA HART loop signaling and prevents propagation of transient voltage spikes across connected devices.

Frequently Asked Questions

Q: Does the AEP9D support hot-swapping of input lines?
A: Input lines can be maintained individually; however, hot-swap procedures require sequential disconnection to avoid output voltage collapse on dependent loads.

Q: What is the switching behavior during line redundancy activation?
A: Switching between Line A and Line B occurs automatically without mechanical relays, ensuring minimal transient impact within 1-2 ms for downstream circuits.

Q: Can the output ports handle extended cable runs without voltage drop?
A: The outputs are designed for distribution within the standard cabinet environment. For runs exceeding 5 m, voltage drop must be evaluated according to cable AWG and current rating.

Field Installation Guidelines

1. Mount the AEP9D on a grounded DIN rail or bracket ensuring functional ground connection to cabinet chassis.
2. Route Line A and Line B separately, avoiding parallel routing to high-power AC conductors.
3. Connect each output branch to intended terminal boards using 3-pin MATE-N-LOK connectors, maintaining polarity (+24P, –24N, FG).
4. Verify total input current does not exceed 20 A; balance loads per line to prevent thermal overload.
5. Ensure environmental airflow allows operation within 0 degC to 55 degC; avoid obstructing cooling paths.

Specifications

• Brand: Yokogawa

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems