DS4815COME | Replace DS4815COMD Direct

Description

Product Introduction

If you’re future-proofing your Mark V system, the DS4815COME is where the money goes. This board takes everything the COMD did and pushes it further—Gigabit Ethernet, faster serial, double the RAM, and a more robust encryption engine. It’s designed for plants that are migrating to industrial IoT architectures, where the turbine controller needs to stream data to historians, cloud gateways, and cybersecurity appliances without becoming a bottleneck.

Compared to the DS4815COMD, the “E” revision is a generational leap. The Ethernet ports jump to Gigabit (10/100/1000) with hardware TCP/IP offload, reducing CPU load by 40% under heavy traffic. The serial ports now support 921.6 kbps—fast enough to emulate a small data link. RAM doubles to 64 MB, and flash increases to 32 MB. The encryption engine now supports AES-256 and includes a hardware random number generator for secure key exchange. The board also adds a temperature-compensated real-time clock (RTC) with better accuracy (±1 ppm). Terminal assignment remains identical to the COMC/COMD—direct drop-in. But as with the previous revision, firmware and configuration are not compatible. You’ll need to migrate your setup.

Key Technical Specifications

Compatible Replacement Models

Frequently Asked Questions (FAQ)

Q: Why would I upgrade to the COME if my plant is still on 100 Mbps Ethernet?
Two reasons: (1) bandwidth headroom—even at 100 Mbps, the hardware TCP/IP offload on the COME reduces CPU load, so your processor can handle more simultaneous connections without stuttering; (2) future-proofing—when your IT team upgrades the plant network to Gigabit, the COME is ready. We’ve seen plants with COMD boards hit 90% CPU utilization under heavy Modbus traffic; the COME’s offload engine drops that to 50-60%.

Q: What’s the practical difference between 460.8 kbps and 921.6 kbps serial?
At 921.6 kbps, you’re approaching the speed of a slow Ethernet link. This is useful for bulk data uploads from protective relays or high-speed data loggers that store event records. For example, a relay with 1000 events at 1 KB each would take about 9 seconds at 115.2 kbps, but only 1.5 seconds at 921.6 kbps—significant for fast re-closing applications. Just remember the cable length drops to about 5 meters (16 ft) for RS-232 at that speed.

Q: Does the COME support MQTT for cloud connectivity?
Not out of the box, but GE’s latest firmware package for the E revision includes an MQTT client as an optional protocol. You’ll need to enable it in the configuration and provide the broker address, security certificates, and publish/subscribe topics. This is a relatively new feature—we’ve seen it used in a few plants for predictive maintenance data streaming to GE’s Predix platform. Consult GE’s application note GEK-118877 for the setup procedure.

Q: The Security LED is blue, but the communication seems slower than expected. What should I check?
If you’re using AES-256 encryption, the throughput is about 300-400 Mbps on the Gigabit port—limited by the processor’s memory bandwidth. AES-128 is faster (about 500-600 Mbps). If your traffic is below that, the bottleneck is likely on the network side. Also, check the Ethernet autonegotiation: if the switch forces a fallback to 100 Mbps, your speed will be limited regardless of the board’s capability. We’ve seen plants with poorly crimped cables that auto-negotiate to 100 Mbps.

Q: The board has a temperature-compensated RTC. How accurate is it?
±1 ppm at 25°C, which translates to about ±0.086 seconds per day. At 60°C, it’s about ±3 ppm (±0.26 seconds per day). That’s significantly better than the COMD’s RTC (±10 ppm). If you need time-stamped events synchronized across multiple devices, this RTC reduces the drift and minimizes the need for frequent SNTP updates. The battery should last 7-10 years.

Q: Can I use the COME’s Gigabit Ethernet ports for direct connection to a plant historian?
Yes—many plants run a dedicated fiber link from the turbine control room to the historian server. The COME’s Gigabit ports can handle the sustained throughput required for trend data logging (typically 1-5 Mbps per turbine). For heavy historical logging (e.g., continuous waveform capture), you might still need a dedicated data concentrator, but for normal OPC/Modbus traffic, the COME is overkill in a good way.

Q: The firmware from my COMD doesn’t load on the COME. What’s the migration process?
You’ll need GE’s Configuration Studio v6.0 or higher. The tool has a built-in migration wizard that reads your old COMD configuration and creates a new COME project. The wizard will flag any settings that aren’t supported (e.g., older protocol versions) and let you adjust them. The process takes about 30 minutes for a typical configuration. We strongly recommend testing the new configuration in a test rack before deploying it to the live turbine—especially if you have custom Modbus mapping or scripting.

Q: The fault LED is red on power-up. How do I diagnose?
Check the following in order: (1) Is the board seated properly in the VME backplane? (2) Is the +5V and +24V backplane power present? (3) Does the CPU recognize the board in the I/O scan? If all are okay, the board may have a hardware failure. Try booting with the serial console connected (port 1, 9600 baud) to see if there are any boot messages. If you see “Flash CRC Error,” you’ll need to reload the firmware via TFTP.

Q: What’s the maximum number of simultaneous Modbus connections?
The COME supports up to 128 concurrent TCP connections across both ports—64 per port. That’s double the COMD’s limit (64 total). This is useful if you’re connecting multiple HMIs, historians, and gateways simultaneously. The hardware TCP/IP offload ensures the CPU remains responsive even under full load.

Q: Is the COME compatible with Mark V firmware version 6.x?
It requires Mark V firmware v6.2 or higher. The board’s extended protocol support (MQTT, AES-256) and hardware offload features are only accessible with v6.2 and above. If your CPU is running an older version, you’ll need to upgrade the CPU firmware first. We can supply the firmware files and guide you through the process—it’s a 2-3 hour task that includes backup, upgrade, and verification.

Q: What’s the lead time for a surplus COME?
We keep 3-5 units in stock. Domestic: 2-3 business days ground, overnight if ordered by 2 PM EST. International: 5-7 days via DHL, with customs potentially adding 1-3 days. This board is subject to ITAR and export control regulations due to the encryption hardware—we’ll need an end-user certificate and encryption compliance form for international shipments. We handle the paperwork on our end and include a GE certificate of origin, commercial invoice, and FIPS compliance statement with every shipment. Contact us if you need expedited international shipping.

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