Description
Product Overview
The GE 8121-DI-DC (originally GE Intelligent Platforms / MTL, later acquired by Emerson) is a 16-channel non-isolated digital input module belonging to the PAC8000 remote I/O platform. This module is designed to collect 24VDC discrete signals from field devices including limit switches, valve position feedback, proximity sensors and relay dry contacts. It plugs onto PAC8000 railbus carrier bases, featuring configurable input debounce filtering, signal latching and pulse counting capability. PAC8000 was originally released under GE Intelligent Platforms, so this part is widely referenced as GE 8121-DI-DC in power, oil & gas and petrochemical spare inventory systems. It acts as a direct drop-in replacement spare for existing PAC8000 DCS remote I/O racks.
Technical Specifications
| Parameter | Details |
|---|---|
| Part Number | 8121-DI-DC |
| Original Manufacturer | GE Intelligent Platforms / MTL Instruments (now Emerson) |
| Product Category | Digital / Discrete Input Module |
| Platform | PAC8000 Remote I/O System |
| Channel Count | 16 points, non-isolated |
| Field Input Voltage | 24 VDC, operating range:18 ~ 30 VDC |
| On-state Input Current | >1.2 mA |
| Off-state Leakage Current | <0.3 mA |
| Minimum Detectable Pulse Width | 5 ms |
| Max Pulse Frequency (Pulse Counter Mode) | 100 Hz |
| Railbus Supply | 12 VDC, typical consumption 90 mA |
| Input Debounce Filter | 2~512 ms software selectable |
| Environmental Rating | ISA G3 corrosive environment compliant |
| Operating Temperature | -40°C ~ +70°C |
| Storage Temperature | -40°C ~ +85°C |
| Relative Humidity | 5% ~ 95%, non-condensing |
| Mounting | PAC8000 DIN rail carrier base |
| Matching Field Terminal | 8617-FT-NI |
| Approximate Weight | 0.21 kg |
Compliance & Certifications
- ATEX / IECEx certification for Zone 2 hazardous area installation
- FM non-incendive approval for Class I Div 2 locations
- CE mark for EMC and Low Voltage Directive
- RoHS compliant
- Full factory functional testing before shipment
Storage & Installation Guidelines
Storage Requirements
- Store in dry, temperature-controlled warehouse; recommended ambient 10°C ~30°C, RH <70% non-condensing
- Keep sealed inside original anti-static packaging before installation
- Protect against heavy mechanical shock, continuous vibration, dust and corrosive vapors
- ESD wristband required for unpacking and PCB handling
Installation Instructions
- Remove power to PAC8000 railbus carrier before module replacement
- Wear ESD protective gear to prevent electrostatic damage to circuit components
- Insert module into designated carrier slot and lock the mechanical keying to prevent wrong module insertion
- Wire 24VDC field discrete signals to 8617-FT-NI removable terminal block following GE PAC8000 wiring schematics
- Verify wiring continuity and field loop integrity
- Restore railbus power, download I/O configuration and run full channel diagnostic test
- Hazardous area installation and commissioning must be completed by certified automation technicians
FAQ
Q: Why is 8121-DI-DC called both GE and Emerson? A: PAC8000 series was originally developed by GE Intelligent Platforms with MTL. Later MTL was acquired by Emerson. Many plant spare lists retain the GE branding for this part number.
Q: Are input channels galvanically isolated? A: Channels are non-isolated; there is 250VAC isolation between field channels and railbus backplane.
Q: Does this module support pulse counting? A: Yes, pulse counting and input latching functions can be activated via software configuration.
Q: What hazardous locations can this module be deployed in? A: Approved for ATEX Zone 2 and FM Class I Division 2 non-incendive applications.
Q: What warranty is available? A: Standard 12-month warranty applies for fully tested modules under rated normal operating service conditions.
Start Chat
Send an Email
