Cost-Smart Serial Connectivity for Modicon Momentum
Downtime in a control cabinet rarely comes from the processor. It comes from the communication path. The 172JNN21032 from Schneider Electric solves that problem as a serial link adapter module inside the Modicon Momentum automation platform. It gives your existing Momentum I/O base a selectable RS-232 or RS-485 serial link with a dedicated 9-pin D-shell Modbus Plus connector. Instead of replacing an entire rack, you restore serial communication at a fraction of the cost.
What This Module Actually Does
The 172JNN21032 is a serial link option adaptor with a single communication port. It draws its supply through the I/O base, so no separate power supply is needed. One communication LED shows operational state at a glance, which shortens troubleshooting time and reduces the labor cost of every service call. The module uses a Lexan housing and carries a conformal coating (Humiseal 1A33) that protects the electronics in dusty or humid plant environments.
Key Parameters and Their Cost Impact
| Specification | Value |
|---|---|
| Product line | Modicon Momentum |
| Communication port | RS-232 or RS-485, selectable |
| Electrical connection | 1 x 9-pin D-shell, Modbus Plus |
| Rated supply voltage | 5 V DC (via I/O base) |
| Input voltage tolerance | +/- 5 % |
| Current consumption | 700 mA at 12 V DC |
| Protection class | IP20 (IEC 529) |
| Operating temperature | 0 to 60 °C |
| Storage temperature | -40 to 85 °C |
| Relative humidity | 5 to 95 %, non-condensing |
| Operating altitude | <= 2000 m |
| Battery | Lithium, 2/3 AA, 5-year life |
| Net weight | 85.05 g |
| Certifications | UL, CSA, NEMA 250 type 1, CE marking |
Three numbers deserve attention. First, the 5-year lithium battery life means fewer scheduled battery replacements and lower maintenance spend. Second, the +/- 5 % input voltage tolerance lets the module ride through small supply fluctuations instead of failing. Third, the IP20 rating and conformal coating keep the unit reliable in clean, controlled cabinets, avoiding premature replacement costs.
Where It Fits in Real Plants
Legacy line upgrades. A food processing plant running a Momentum rack can add serial communication without a full platform migration. The 172JNN21032 slots into the existing base, so the upgrade cost stays in the hundreds rather than the thousands.
Remote panel monitoring. Water treatment skids often sit far from the main control room. The selectable RS-485 link supports longer cable runs, and the Modbus Plus connector ties the panel back to the supervisory system. One adapter replaces a separate gateway box.
Spare parts strategy. Because the module is compact (25 mm high, 143.1 mm wide, 60.06 mm deep) and light at 85.05 g, storeroom space is minimal. Holding one spare on the shelf costs almost nothing compared to a day of lost production.
Installation and Setup Notes
Mount the module in a standard Momentum I/O base. Confirm the base supplies 5 V DC, because the adapter takes power from the base rather than a dedicated feed. Select RS-232 or RS-485 according to your cable length and noise environment. Terminate the 9-pin D-shell Modbus Plus connection per the manufacturer’s documentation. Keep the cabinet within 0 to 60 °C and below 2000 m altitude. Route serial cables away from drives and contactors to reduce electromagnetic interference. The module resists 10 V/m fields from 80 to 1000 MHz and 8 kV electrostatic discharge on air, so it tolerates typical industrial noise when installed correctly.
Reliability and Long-Term Cost
The 172JNN21032 resists shock at +/- 15 gn for 11 ms and vibration at 1 gn from 57 to 150 Hz. Those ratings matter in plants with nearby presses or conveyors. The lithium battery gives roughly 30 days of autonomy after a low-battery indication at 40 °C, which is enough warning to schedule a planned swap. Inspect the communication LED periodically and follow the manufacturer’s safety manual for all maintenance. Verify current lifecycle status and availability with SpareTechPLC before ordering.
Compatibility and Integration
The module belongs to the Modicon Momentum automation platform and communicates over RS-232 or RS-485, with a 9-pin D-shell Modbus Plus connection. It carries UL, CSA, and NEMA 250 type 1 certifications and CE marking, so it fits North American and European panel builds. If your controller already speaks Modbus Plus, integration is straightforward and avoids the cost of protocol converters.
What to Check Before You Buy
Confirm your I/O base provides 5 V DC and that your controller supports Modbus Plus or a serial link. Verify the cabinet stays within the 0 to 60 °C operating range and below 2000 m altitude. Check that IP20 protection suits your environment; washdown areas need a different enclosure. SpareTechPLC stocks industrial automation parts and can confirm compatibility with your existing Momentum hardware.
Frequently Asked Questions
Does the 172JNN21032 need an external power supply?
No. It receives its 5 V DC supply through the I/O base, which reduces wiring cost and cabinet space.
How long does the lithium battery last?
Approximately 5 years. After a low-battery indication at 40 °C, you have under 30 days of autonomy to replace it.
Which serial protocols does it support?
It supports a selectable RS-232 or RS-485 serial link and connects through a 9-pin D-shell Modbus Plus connector.
What is the operating temperature range?
From 0 to 60 °C in a non-condensing environment, with storage from -40 to 85 °C.
Is the module certified for industrial use?
Yes. It carries UL, CSA, NEMA 250 type 1, and CE marking, and conforms to IEC 529 for IP20 protection.
