Description
Product Introduction & Engineering Value
The 502-03944-00 is a motion-network interface rather than a conventional analog or discrete I/O card. Its job is to connect the PiC900 controller to SERCOS-based digital drives through fiber-optic communication. The documented configuration supports two SERCOS rings, with each ring accommodating from one to eight digital drives.
For maintenance teams keeping older Giddings & Lewis machine tools in production, this distinction matters. A failed SERCOS interface can present as a collection of apparently unrelated motion faults—drive communication loss, axis initialization failure, or inability to establish the expected drive network. Replacing the correct interface module can therefore be considerably less disruptive than attempting a wholesale control retrofit.
Technical Specifications
SERCOS Communication
The module provides two SERCOS ring interfaces for the PiC900 control architecture. The documented application is communication with digital drives rather than direct motor-current control. The module uses optical communication through SMA connectors and 1000 µm plastic fiber-optic cable.
| Specification | Value |
|---|---|
| SERCOS architecture | Dual-ring |
| Maximum drives | Up to 8 digital drives per ring |
| Optical connector | SMA female |
| Fiber type specified by PiC900 documentation | 1000 µm plastic optical fiber |
| Update/service port | RS-232 |
| Logic-side supply | 5 VDC |
| Logic-side current | 575 mA |
| Operating temperature | 7°C to 55°C |
| Storage temperature | -40°C to 85°C |
| Humidity | 5–95%, non-condensing |
| EMC | EMC compliant per PiC900 documentation |
| UL / C-UL | Listed; documentation cites file E126417 |
| Physical size | 1.6 × 12 × 8.4 in. including latch |
| Vibration | 10–57 Hz at 0.15 mm; 57–2000 Hz at 2 g |
| Shock | Four shocks/axis, 15 g / 11 ms |
The environmental and mechanical specifications above come from the PiC900 Controls product documentation rather than from a reseller listing.
Important Part-Number Relationship
There is useful historical evidence linking the numbers:
502-03944-00 → M.1016.9428 → M.1016.9428Rxx
Radwell identifies M.1016.9428 as the replacement/associated designation for 502-03944-00 and describes it as an industrial programmable computer with a dual-ring SERCOS interface.
The R13 suffix supplied with this unit should be treated as a revision/build identifier. Do not automatically assume that every M.1016.9428 revision is electrically interchangeable without checking the machine’s PiC900 hardware configuration and existing drive-network requirements.
502-03944-00
502-03944-00
Field Application & “Trench” Experience
Typical Application
The 502-03944-00 is most relevant to legacy Giddings & Lewis CNC and machine-tool control systems using the PiC900 architecture. Its SERCOS interface allows the controller to communicate with multiple digital drives over optical rings.
Plausible maintenance scenario:
A machining center suddenly reports multiple drive communication faults after a control-cabinet maintenance event. Individual drives still power up, but the PiC900 cannot establish the expected SERCOS network. A technician swaps drives one at a time and sees no improvement. The eventual finding is a failed optical communication interface rather than eight simultaneous drive failures.
That is the kind of failure pattern that makes this board strategically important in a legacy-spares inventory.
Niche Applications
- Giddings & Lewis CNC machining centers
- Heavy-duty machine tools using PiC900 motion control
- Legacy multi-axis systems with SERCOS digital drives
- Production equipment where control-system replacement is substantially more expensive than maintaining the existing PiC900 architecture
Transparency SOP: QA & Testing
For New Surplus inventory, the important issue is not merely whether the board looks unused. The part number, revision marking, connector condition, optical interfaces, and packaging should all be documented.
Recommended Incoming Inspection
- Part-number verification
Confirm the assembly is marked or labeled consistently with 502-03944-00 / M.1016.9428. - Revision verification
Record the complete board marking, including R13. Do not remove the revision information from the purchasing record. - PCB inspection
Check for corrosion, contamination, cracked solder joints, damaged components, lifted traces, and signs of previous thermal exposure. - SERCOS optical inspection
Inspect both SMA interfaces for mechanical damage and contamination. Optical connectors should not be treated as ordinary electrical connectors. - Power verification
Where suitable test equipment and the correct PiC900 test environment are available, verify the 5 V logic supply and approximately 575 mA logic-side requirement against the system documentation. - Functional verification
The preferred test is installation in a compatible PiC900 environment with known-good SERCOS drives and verification of ring initialization and drive communication.
New Surplus vs. Refurbished
New Surplus: unused inventory outside the original manufacturer’s normal distribution channel. It should not automatically be represented as factory-new with an active OEM warranty.
Refurbished: previously used equipment that has undergone inspection, repair and/or functional testing. The exact repair and test scope should be documented.
This distinction matters with legacy Giddings & Lewis hardware because reseller warranties are not equivalent to an original manufacturer’s warranty. For example, Radwell explicitly states that its warranty may apply even when the original factory warranty does not.
Veteran’s Tech Trap Guide
⚠️ Trap #1 — Don’t confuse it with the one-ring module
The PiC900 documentation identifies:
- M.1016.9428 / 502-03944-00 = two-ring SERCOS module
- M.1016.9429 / 502-03944-10 = one-ring SERCOS module
They are not simply different labels for the same board. If the machine configuration requires two SERCOS rings, ordering the one-ring version is the wrong repair.
⚠️ Trap #2 — Don’t call this a servo amplifier
Some third-party listings incorrectly characterize this part as a servo amplifier or spindle-drive module. The PiC900 documentation is much clearer: this is a SERCOS module that interfaces the controller with digital drives. It does not replace the drive power stage.
⚠️ Trap #3 — Revision matters
Your specified M.1016.9428R13 should be recorded exactly as supplied. Other listings document R6 and R10 variants of the M.1016.9428 family, demonstrating that multiple revision levels exist.
PRO TIP: When purchasing a legacy motion-control board, send the supplier a photograph of the complete label and PCB revision whenever possible. The base part number alone is not enough evidence for revision-sensitive replacement work.
Dynamic FAQ
Is 502-03944-00 the same basic product as M.1016.9428?
Yes. The PiC900 documentation identifies M.1016.9428 as the two-ring SERCOS module and lists 502-03944-00 as the older part number. Radwell likewise identifies M.1016.9428 as the replacement/associated designation for 502-03944-00.
What does R13 mean in M.1016.9428R13?
R13 should be treated as a board revision/build designation. Because multiple revision levels are documented in the aftermarket repair and supply ecosystem, procurement should specify the complete M.1016.9428R13 marking rather than ordering only “M.1016.9428.”
How many drives can the two-ring SERCOS module support?
The PiC900 documentation specifies up to eight digital drives per SERCOS ring, with two rings available on the M.1016.9428 module.
Does this board directly power the servo motors?
No. It is a SERCOS communication/interface module. It provides the communications path between the PiC900 controller and digital drives. It should not be substituted for a servo amplifier or drive power module.
Is 502-03944-00 still a current OEM part?
Available evidence indicates that 502-03944-00 is a legacy/discontinued designation, with M.1016.9428 used as the later/associated part number in commercial replacement listings. This makes revision verification and installed-base compatibility particularly important when sourcing a replacement.
How should I verify a New Surplus 502-03944-00 is authentic?
Request clear photographs of the part-number label, PCB marking, revision code, SERCOS connectors, and overall board condition. The supplied revision should specifically be documented as M.1016.9428R13. For a high-value legacy control component, a supplier’s warranty and test report should also be distinguished from an OEM factory warranty.
What warranty should procurement expect?
Warranty terms depend on the supplier and condition category. Do not assume that a New Surplus unit carries an active Giddings & Lewis factory warranty. Third-party suppliers may provide their own warranty; for example, Radwell currently advertises a two-year warranty on its applicable inventory, while other repair suppliers advertise their own coverage.
Procurement recommendation: Specify the complete identification as Giddings & Lewis 502-03944-00, M.1016.9428R13, PiC900 Two-Ring SERCOS Module and require confirmation of revision, condition, test status, and warranty before purchase.
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