Omron CS1W-CT021 High-Speed Counter Unit for CS1 Platform

The CS1W-CT021 is a dedicated high-speed counter module for Omron CS1 series programmable logic controllers. It accepts inputs from two independent incremental encoders (RS-422 line driver or 24V DC open collector) and provides real-time counting, comparison, and control outputs for precision motion and production monitoring.

Counting Performance

Maximum counting frequency: 500kHz per channel. Resolution up to 32-bit counters (rolling over at 2³¹-1). Modes include linear counter, ring counter, and rotational speed measurement. The module can handle square-wave signals with phase shift (A/B/Z) or direction/pulse inputs. Each channel has a preset value and two comparison registers for triggering events.

Digital I/O and Interrupts

Four built-in output points (transistor, 24V DC, 0.5A) can be mapped to comparison results or external control commands. Interrupt tasks can be generated at target counts, enabling rapid response without CPU scanning delay. The CT021 also features a latch input to capture current count value on an external signal, useful for registration mark sensing.

Configuration and Software

Setup is performed via CX-Programmer or dedicated CX-Position software. Parameters such as count direction, filter time, and hysteresis are stored in non-volatile memory. The module supports online monitoring of count values and output status. Error diagnostics include encoder wire break and over-speed detection.

Physical and Environmental

PCB dimensions compatible with CS1 backplane, consuming 0.45A from 5V rail. Operating temperature 0-55°C, storage -20-75°C. Terminal block accepts 0.2-1.5mm² wires. LED indicators for power, count activity, output state, and error. The unit is CE and UKCA marked, with RoHS compliance.

Typical Applications

Used in cut-to-length machines, conveyor belt positioners, winding machines, and assembly line indexing. For multi-axis applications, multiple CT021 units can be installed in a single rack. The high-speed nature eliminates the need for external counters, reducing panel space and wiring.

Maintenance and Reliability

Mean time between failures exceeds 250,000 hours. Firmware is field-updatable via the PLC CPU. In case of CPU stop, the counter can freeze or continue counting based on configuration. All parameter settings are backed by EEPROM, surviving power loss.

Conclusion

The Omron CS1W-CT021 transforms a standard CS1 PLC into a powerful motion and production counter. Its dual-channel 500kHz capability competes with standalone counters while offering full integration with Omron automation environment.