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KOYO SR-21-EX PLC Controller for Industrial Automation
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KOYO SR-21-EX
Reliable and compact PLC for small-scale industrial automation, offering robust I/O and flexible communication at an economical price point
| Brand | KOYO |
| Model | SR-21-EX |
| Voltage | 24V DC |
| Country of Origin | Japan |
| Weight | 0.8 kg |
| Dimensions | 140x90x80 mm |
| Warranty | 6 months |
| Certifications | CE, UL, RoHS |
| SKU / MPN | SR-21-EX |
| What’s in the box | PLC unit, mounting screws, user manual, I/O connector set |
| CPU Type | 16-bit RISC processor |
| Program Memory | 32 KB |
| Digital Inputs | 12 inputs (24V DC) |
| Digital Outputs | 8 outputs (relay, 2A) |
| Communication Ports | RS-232C, RS-485 |
| Programming Software | KOYO SoftPro (Windows compatible) |
Key benefits: Easy ladder logic programming, robust relay outputs, built-in communication ports, compact DIN-rail mountable design, long-term availability for legacy system support
Typical applications: Packaging machinery, conveyor systems, small material handling, HVAC control, water treatment, simple machine automation
Lifecycle: Active product, supported for 5+ years with spare parts availability
1 review for KOYO SR-21-EX PLC Controller for Industrial Automation
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Exact match for many brands
We make replacements easy with an exact match for almost any brand.
We use OEM catalogs to match your part number
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Competitively priced
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Orders usually ship the same day
Rest assured your order will arrive as soon as possible knowing we usually ship the same day.
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Guaranteed for one full year
All of our New Surplus and Reconditioned products come with a 1 year warranty.

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Michael T. –
Tested the proximity switch, response time is spot on. Recommended for industrial use.