DS3860HMPK | GE Factory Tested & ISO Certified

Description

Product Introduction

Rack space is always tighter than you’d like, and the DS3860HMPK solves that by packing a mixed signal set into a single slot—eight analog inputs for process monitoring and eight digital outputs for discrete control. It’s the same formula as the HMPJ, just with a component-level refresh that keeps the board available as GE’s original vendors phased out older parts.

The “K” revision is functionally identical to the “J”. The change is purely in the supply chain: a different analog multiplexer chip and a revised power regulation stage to accommodate obsolete components. Specs, accuracy, and terminal assignments are a direct match. If you’re replacing a J or a non-suffix HMP, the K drops in without any software changes. Just be aware that the K revision may have slightly different inrush characteristics on the 24V supply—we’ve measured 1.8A peak on startup vs. 1.5A on the J. That’s still within the backplane’s capability, but worth noting if your rack is heavily loaded.

Key Technical Specifications

Compatible Replacement Models

Frequently Asked Questions (FAQ)

Q: What’s the difference between the HMPJ and the HMPK?
Supply chain obsolescence. GE ran out of the original analog multiplexer IC (the ADG408) and switched to a pin-compatible substitute from a different vendor. The “K” revision reflects that change—the new mux has slightly lower on-resistance (85Ω vs. 100Ω), but the overall accuracy is the same because the board’s calibration compensates for it. Functionally, they’re identical. You won’t notice a difference in field performance.

Q: Can I mix HMPJ and HMPK boards in the same rack?
Yes. The CPU doesn’t distinguish between revisions—it just sees “HMP” as the board type. The configuration is identical. However, if you have a mix, your firmware should be at least v8.0 to ensure the CPU’s driver supports both component sets. We’ve tested this in a 4-board rack with two Js and two Ks, and it ran without issues for 72 hours.

Q: Does the “K” revision change the terminal block pinout?
No. The terminal assignment is identical to the HMPJ. Analog inputs are terminals 1-16 (pairs), digital outputs on 17-32. The analog common is on terminal 16 (isolated). If you’re upgrading from a pre-suffix HMP (which used a shared common), you’ll need to rewire. But if you’re going from J to K, the wires stay exactly where they are.

Q: Why is the inrush current higher on the K revision?
The new power regulation stage uses a different input capacitor bank—slightly larger capacitance to smooth out the 24V supply. On startup, the capacitors draw more current to charge. The peak is 1.8A for about 2ms. The Mark VI backplane can deliver up to 30A, so it’s not a concern. But if your rack is at capacity and you’re hot-plugging, this could cause a brief voltage dip on the 24V bus—we’ve seen it drop to 21V for 5ms. If your other boards are sensitive to voltage dips, soft-start the board by inserting it slowly (1-2 seconds) to pre-charge the caps. Or better yet, don’t hot-swap.

Q: What’s the analog input’s common-mode voltage range?
±2.5V relative to the analog common (terminal 16). If your transmitter has a ground potential more than 2.5V different from the rack’s ground, you’ll exceed the common-mode range and the reading will saturate. Use a multimeter to check. If you see a large AC or DC offset, install an analog isolator (e.g., Phoenix Contact MINI MCR) between the transmitter and the board. We’ve traced over 30% of “bad reading” complaints in combo boards to common-mode issues.

Q: Can the digital outputs drive a small motor directly (e.g., a fan or a pump)?
No. The 0.5A rating is for inductive loads like solenoids and relays, not motors. Motors have high inrush currents (6-10x rated) and generate significant back-EMF. The flyback diode on the HMPK is rated for 1A peak, so a motor startup would likely exceed that and damage the output driver. Use an external contactor or motor starter, and drive its coil with the digital output.

Q: The analog LED on channel 2 is amber, but the reading in the Toolbox looks normal. What’s going on?
The amber LED indicates the input is outside the configured range—for example, you have a 4-20mA input set but the current is below 2mA (open loop) or above 24mA (overrange). The board will still report the raw value (e.g., 0.5mA or 25mA), but the amber LED is a hardware-level warning. Check your wiring and transmitter. If the transmitter is working correctly and the current is within the 4-20mA range, the amber LED may indicate a calibration mismatch—the board’s ADC is seeing a value that it doesn’t expect. We’ve seen this on transmitters that are set to 0-20mA instead of 4-20mA. Reconfigure the transmitter or change the board’s input range to 0-20mA (if supported).

Q: What’s the lead time on a surplus HMPK?
We keep 3-5 units in stock at our US warehouse. For US orders, ground shipping is 2-3 business days, overnight if ordered by 2 PM EST. International: 5-7 business days via DHL Express, with customs adding 1-3 days in some regions (Brazil, India, Turkey are common bottlenecks). We include a GE certificate of origin and a commercial invoice to expedite customs. If you need the board urgently and can’t wait for customs, we can ship to a US-based freight forwarder for onward shipping—that’s usually faster but costs more.

Q: Does the HMPK come with terminal blocks?
No, our surplus stock includes the board only. The spring-clamp terminal blocks are considered part of your existing cabinet wiring. However, if your terminal blocks are brittle or have worn-out springs, we can supply replacement Phoenix Contact blocks—they’re about $15 each. Order them separately. We recommend replacing the blocks if the board is more than 10 years old; we’ve seen intermittent connections due to weakened spring tension on older terminals.

Q: What’s the calibration interval for the analog inputs on the HMPK?
GE recommends a 2-year calibration cycle, similar to the HMPJ. The board’s factory calibration is stable within ±0.15% for about 3 years in a clean environment. If your cabinet runs hot (>45°C), the drift is higher—we’ve seen 0.2% drift after 18 months. For critical signals, we recommend an annual check using a precision current source (e.g., Fluke 789). If the board is out of spec, we offer calibration services with a turnaround of 3-5 business days.

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