Schneider Electric TSX3721001 – Modicon TSX Micro CPU for dependable compact machine control

The Schneider Electric TSX3721001 is a Modicon TSX Micro-series CPU that typically runs on 24 VDC and is widely used in small to mid-size machines—packaging cells, conveyors, pumps, and material handling come to mind. From my experience, this CPU is chosen when you want stable cycle times, straightforward serial connectivity (Unitelway/Modbus), and an easy path to expand I/O without jumping to a larger platform.

You might notice that it integrates discrete I/O on the base (model-dependent) and supports the TSX Micro expansion ecosystem for digital and analog modules. Programming is typically done with Schneider’s legacy PL7 environment, which many maintenance teams still favor for its simplicity. One thing I appreciate is how forgiving it is in brownout-prone plants when paired with a solid 24 VDC supply and proper grounding.

Company’s Order Placement Process and Guarantees

• Warranty: 365 days
• Delivery: 1 week if in stock; no more than one month at the latest
• Payment: 50% advance payment, full payment before delivery
• Express delivery: FedEx, UPS, DHL

Key Features

• 24 VDC power input – Stable operation in most control cabinets; easy to integrate with standard industrial power supplies.
• Integrated discrete I/O (model-dependent) – Useful for compact machines where space and wiring time need to be minimized.
• Expandable architecture – Supports TSX Micro expansion modules for additional digital, analog, and specialty I/O as the machine grows.
• Serial communications on-board – RS232/RS485 ports for Unitelway/Modbus; handy for HMIs, drives, and remote I/O in many cases.
• Deterministic control with fast task execution – Reliable cycle times for packaging, indexing, and speed-sensitive sequences.
• Battery-backed memory and real-time clock – Keeps key data and time-stamps through power loss events.
• Programmed with PL7 – Well-known legacy software, typically simple for maintenance teams to support.
• Industrial temperature range – Designed for 0…55 °C environments common to factory floors.

Technical Specifications

Related or Supporting Products

• TSX3722001 – Similar CPU with AC power input; a practical pick where 100–240 VAC is already present in the cabinet.
• TSX3710101 – Entry-level TSX Micro CPU with reduced resources, often used in very compact panels.
• TM221C/ TM241 (Modicon M221/M241) – Modern alternatives when migrating to current platforms; not drop-in but helpful for new designs.
• RS232/RS485 programming adapters (e.g., USB–RS485 gateway) – Typically used to program via the TER/AUX port and connect HMIs on Modbus/Unitelway.
• TSX Micro expansion I/O modules – Digital and analog cards to scale I/O count, commonly added as machines evolve.

One of our OEM clients swapped a failing small PLC for a TSX3721001 on a pick-and-place line and mentioned the biggest gain was faster troubleshooting—simple ladder, clear I/O status LEDs, and predictable serial comms to the drive.

Installation & Maintenance

• Cabinet environment – Mount in an enclosure meeting IP20 or better; allow ventilation space above/below for natural convection.
• Power and grounding – Use a regulated 24 VDC supply with proper protective earth. From my experience, adding a dedicated DC breaker and transient suppression improves uptime.
• Wiring – Keep serial lines (RS232/RS485) away from motor cables; use twisted pair and shielded cable for RS485, grounding the shield at one end.
• I/O expansion – Power budget the backplane and expansion modules; verify current draw before adding cards.
• Routine maintenance – Back up the program after any change, check and replace the battery per schedule (typically every 3–5 years), and clean dust from vents. Firmware updates are uncommon on legacy units, but verify revision alignment when replacing hardware.
• Safety – Lock out power before wiring, comply with local standards, and validate emergency stop circuits with certified safety components.

Quality & Certifications

• CE compliant
• UL/cUL listed (typical for TSX Micro family)
• RoHS conformity may vary by production date; most units in later production runs comply
• Manufacturer warranty policy: Schneider Electric terms apply; our supply warranty is 365 days