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The NTDI21-A is a Digital Input Termination Unit associated with the ABB Bailey INFI 90 process control platform.
The termination unit belongs to the field-interface portion of the control system. It provides the physical termination and signal interface between field wiring and the corresponding control-system I/O circuitry.
In an INFI 90 installation, the termination unit should not be treated as a standalone PLC or DCS processor. Instead, it works as part of the overall I/O signal path, providing the connection point between field devices, termination wiring, and the associated I/O module.
This distinction is important when selecting a replacement: NTDI21-A should be matched against the existing termination-unit part number and the associated I/O module/application rather than selected only by the general description "digital input module.
Request a Quote
Contact us with the required quantity and your existing system/module information. We can confirm the available NTDI21-A version, condition, inspection options, and delivery schedule before order confirmation.
| Parameter | Details |
|---|---|
| Brand | ABB Bailey |
| Product Family | Bailey INFI 90 |
| Product Type | Digital Input Termination Unit |
| Model | NTDI21-A |
| Part Number | NTDI21-A |
| System | ABB Bailey INFI 90 |
| Application | Industrial Automation / Process Control |
| Component Category | Termination Unit |
| Condition | New / Original |
| Country of Origin | Confirm before shipment |
| Warranty | 12 Months |
| Dimension | 25*25*8cm |
| Weight | 0.55kg |
| HS code | 8471609000 |
| Shipping | DHL / FedEx / UPS / TNT or customer-appointed forwarder |
ABB NTDI21-A Functions
The NTDI21-A is used as part of the digital input signal interface in an ABB Bailey control system.
Typical functions include:
*Providing termination points for field digital signals.
*Connecting field wiring to the corresponding INFI 90 I/O architecture.
*Providing the required signal routing between field wiring and the associated I/O module.
*Supporting organized field wiring within the DCS cabinet.
*Allowing field-side signals to be connected according to the system engineering configuration.
*Simplifying maintenance and replacement of the termination-unit portion of an existing INFI 90 installation.
The exact wiring, jumper/dipshunt configuration, and associated I/O module should be verified against the applicable ABB Bailey documentation before installation.
Compatible Control System:
ABB Bailey INFI 90 Process Management System
ABB Bailey's INFI 90 architecture uses termination units as the interface between plant field wiring and process-control I/O modules. ABB documentation for other INFI 90 termination units describes this general architecture, including field wiring, termination panels, and associated I/O modules.
For replacement projects, compatibility should be checked using:
Existing termination-unit part number
Existing I/O module
Cabinet / termination-panel arrangement
Field wiring configuration
Jumper or dipshunt configuration where applicable
Existing system documentation
Related ABB Bailey Termination Units
The following ABB Bailey termination units belong to related INFI 90 termination-unit families and may appear in the same maintenance or replacement projects:
NTDI01 / NTDI01-A
Digital I/O Termination Unit
NTDI02
Digital I/O Termination Unit
NTDO02
Digital Output Termination Unit
NTRO02-A
Digital Output Relay Termination Unit
NTRO03-A
Digital Output Relay Termination Unit
NTAI05
Analog Input Termination Unit
NTAI06
Analog Input Termination Unit
NTCS04
Control I/O Termination Unit
NTMP01
Multi-Function Processor Termination Unit
NTRL02B
Remote I/O Termination Unit
NTST01
Time Synchronization Termination Unit
NTAI02
Termination Unit
FAQ
01. What system does NTDI21-A belong to?
02. Does the NTDI21-A require configuration before installation?
03. What information is required to verify NTDI21-A compatibility?
04. How can I request a quotation?
05. Can you provide actual photos?
06. Can you verify the part number before shipment?