DS3800HEDB | GE Mark V 24V DC Output Module

Description

Product Introduction

The DS3800HEDB is the high-density 24V DC output board, offering 32 channels in a single Mark V slot—twice the density of the 16-channel boards we’ve covered. This board uses MOSFET outputs with built-in flyback diodes, making it ideal for driving 24V DC solenoids, relays, and indicator lamps in applications where cabinet space is at a premium. The 32-channel capacity reduces the number of I/O modules needed, freeing up rack slots for other functions. The board’s 0.5A per channel rating is suitable for most 24V DC field devices, though you’ll need to manage the total current if driving multiple loads.

We’ve used the HEDB in skid-mounted turbine control packages where rack space was limited—the 32-channel density allowed us to drive 64 outputs with just two boards. The MOSFET outputs switch in about 1ms, and the built-in flyback diodes protect against inductive kickback from solenoids. The status LEDs show the output state, powered from the 5V logic rail. The board’s backplane current draw is 1.2A, which is moderate for a 32-channel board. The HEDB is a solid choice for high-density 24V DC output applications.

Key Technical Specifications

Compatible Replacement Models

Frequently Asked Questions (FAQ)

Q: What’s the total aggregate current capacity of the HEDB?
A: The HEDB has a total aggregate current limit of 8A across all 32 channels. Each channel is rated at 0.5A continuous, so the theoretical maximum is 16A—but the board is limited to 8A total. This means you can’t run all 32 channels at 0.5A simultaneously. If you have 32 channels at 0.25A each, that’s 8A total, which is fine. If you need more current, you’ll need to distribute loads across multiple boards.

Q: Can I drive a 24V DC solenoid with the HEDB?
A: Yes, as long as the solenoid’s current is under 0.5A (resistive) or 0.25A (inductive) per channel. The board’s flyback diode will protect the MOSFET from inductive kickback. If your solenoid draws more than 0.25A, consider using an external contactor or a higher-current output board. The HEDB is designed for low-current 24V DC loads, not heavy solenoids.

Q: The HEDB has 32 channels. Does it use a different backplane connector than the 16-channel boards?
A: Yes. The HEDB uses a higher-density backplane connector to accommodate 32 channels. While the physical footprint is the same as other Mark V boards, the connector has more pins. You cannot plug a 32-channel board into a slot that was wired for a 16-channel board without re-terminating the harness. The pin assignments are different. Always verify the backplane wiring before installing an HEDB.

Q: The status LEDs are powered from the 5V logic rail. What happens if the field supply is off?
A: The LEDs will still show the output state as commanded by the controller, even if the field supply is off. This can be misleading during troubleshooting. Always verify the field supply voltage at the load terminals with a multimeter. The LED indicates the logic state, not the actual presence of field power. We’ve seen this confusion on field startups.

Q: How do I manage the total aggregate current of the HEDB?
A: The 8A total limit is a hard limit—exceeding it can damage the board’s internal power distribution. To stay within the limit, calculate the total current for all active channels. For example, if you have 24 channels at 0.25A each, that’s 6A total, which is fine. If you have 20 channels at 0.5A each, that’s 10A total—you’ll need to reduce the load or use a second board. The board’s firmware does not have per-channel current limiting; it’s up to you to manage the total current.

Q: Can I use the HEDB with a 12V DC supply?
A: No. The HEDB is designed for 18-30V DC. At 12V, the MOSFETs may not fully turn on, resulting in higher on-resistance and overheating. If you have 12V DC loads, you’ll need a different board or an external voltage regulator. The HEDB is specifically for 24V DC applications.

Q: Does the HEDB have conformal coating?
A: Not by default. The HEDB’s suffix typically indicates termination type, not coating. If you need conformal coating for harsh environments, look for a suffix with a “G” (e.g., DS3800HEDB1G1G). The standard HEDB is suitable for indoor environments. If your plant has high humidity or corrosive conditions, consider a coated variant.

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