CTI (Control Technology Inc.) 901C-2599 Output Module

Technical Dossier

Product Details And Specifications

CTI 901C Series Technical Notes

The CTI (Control Technology Inc.) 901C series represents a family of I/O and control modules engineered for compatibility with Siemens SIMATIC 505 (formerly Texas Instruments TI 505) programmable logic controller platforms. These modules are deployed across heavy industrial sectors including petrochemical refining, power generation, pulp and paper manufacturing, and water treatment infrastructure. The 901C series was designed as a direct functional and form-factor replacement for legacy TI 505 I/O modules, enabling facilities to extend the operational life of installed SIMATIC 505 systems without full platform migration. Installed base penetration remains significant in North American process industries, where the cost and risk of full DCS/PLC replacement justify long-term spare parts procurement strategies.

The Evolution of 901C Architecture

The 901C series emerged as the SIMATIC 505 platform transitioned from Texas Instruments to Siemens ownership in the 1990s. CTI developed the 901C line to address the growing aftermarket demand for compatible I/O modules as original Siemens production of certain 505-series cards was reduced or discontinued. Architecturally, 901C modules use the same backplane bus protocol as the TI 505 and Siemens SIMATIC 505 racks, ensuring transparent interoperability without firmware modification. Early 901C variants focused on discrete I/O replacement; subsequent generations expanded into analog I/O, specialty function modules, and communication adapters. As the SIMATIC 505 platform has entered end-of-life status with Siemens, the 901C series has become the primary supply channel for facilities requiring certified replacement modules. Compatibility spans SIMATIC 505 racks including the 505-6870, 505-6871, and CTI 2500 series controllers.

901C Full Catalog & Functionalities (SKU List)

Discrete Output Modules

• 901C-2599: 16-point 120VAC discrete output module, SIMATIC 505 rack-compatible, isolated outputs
• 901C-2400: 32-point 24VDC discrete output module, sourcing type, high-density I/O
• 901C-2401: 32-point 24VDC discrete output module, sinking type, field-side isolated
• 901C-2500: 16-point 120VAC output module, triac-based solid-state switching
• 901C-2501: 16-point 240VAC output module, high-voltage process applications
• 901C-2600: 8-point relay output module, dry contact, 2A per point

Discrete Input Modules

• 901C-1200: 32-point 24VDC discrete input module, sourcing, high-density rack mount
• 901C-1201: 32-point 24VDC discrete input module, sinking configuration
• 901C-1300: 16-point 120VAC discrete input module, optically isolated
• 901C-1301: 16-point 240VAC discrete input module, high-voltage field wiring
• 901C-1400: 16-point TTL/5VDC discrete input module, logic-level signals

Analog I/O Modules

• 901C-3400: 8-channel analog input module, 4–20mA / 0–10V selectable, 12-bit resolution
• 901C-3401: 16-channel analog input module, differential inputs, process instrumentation
• 901C-3600: 4-channel analog output module, 4–20mA, 12-bit DAC, loop-powered
• 901C-3601: 8-channel analog output module, 0–10V / 4–20mA, dual-range

Specialty & Communication Modules

• 901C-4800: High-speed counter module, 4-channel, quadrature encoder input support
• 901C-5000: PROFIBUS-DP communication adapter, slave mode, 12Mbps