Clarity Control Module SOFTA ELSD

Importance of the Topic

Evaporative light scattering detection (ELSD) is a widely used universal detector for liquid chromatography that responds to non-volatile analytes. Integrating ELSD control into chromatography data systems enhances automation, method reproducibility, and accurate logging of detector settings, reducing the need for external data conversion hardware and manual record-keeping. This integration is crucial for quality control, routine analysis, and research labs that demand robust control and digital acquisition.

Objectives and Overview

The manual describes the integration of the SofTA ELSD series (models 200s, 300s, 400, 1200, 1300, 1400) into the Clarity chromatography station via a dedicated control module. Key goals include establishing reliable serial communication, enabling full remote control of detector parameters, capturing digital signals directly in the software, and providing guidance on installation, configuration, method setup, monitoring, and troubleshooting.

Methodology

The SofTA ELSD is linked to the PC via an RS-232 serial interface using a straight DB9F-DB9M cable. A Digital Input Device (DID01) adapter leverages unused RS-232 pins for TTL signals to trigger acquisition events, such as injection starts. Within Clarity, the Control Module is added through System Configuration, where AutoDetect locates the detector and uploads its serial number. Method parameters are defined in the Method Setup – Acquisition dialog and sent digitally to the detector, eliminating analog-to-digital conversion.

Instrumentation

• SofTA ELSD detectors (models 200s, 300s, 400, 1200, 1300, 1400)
• PC with Clarity software and LC Control module (p/n A24)
• Serial straight DB9F-DB9M cable (p/n SK02)
• Optional Digital Input Device adapter (p/n DID01)

Main Features and Discussion

The control module provides direct digital acquisition at 20 Hz sample rate, with remote adjustment of spray chamber and drift tube temperatures, baseline filter weight, gain modes (Normal or EDR), and shutdown behavior. Calibration scaling and analog output settings remain available but are bypassed when digital acquisition is used. The Device Monitor window offers real-time display of temperatures, filter state, digital input statuses, and allows soft commands such as auto zero and standby toggling.

Practical Benefits and Applications

• Eliminates need for separate A/D converters and analog wiring.
• Ensures method parameters are embedded in recorded chromatograms for audit trails.
• Streamlines sequence programming with automated detector on/off and data logging.
• Enhances reproducibility and reduces setup errors in routine and regulated analyses.

Future Trends and Possibilities

Advancements may include Ethernet or USB connectivity replacing RS-232 for faster data rates and remote diagnostics, integration of ELSD control within cloud-based LIMS platforms, enhanced digital signal processing for lower detection limits, and expanded compatibility with emerging chromatography software ecosystems.

Conclusion

The SofTA ELSD Control Module for Clarity provides comprehensive digital control of ELSD detectors, improving workflow automation, data integrity, and operational efficiency. By simplifying hardware requirements and integrating directly into the chromatography station software, it supports high-throughput labs and stringent quality environments.

Reference

DataApex Ltd. SofTA ELSD Clarity Control Module Manual, Code/Rev. M126/90C, Date 2024-02-14