Description
Core Product Summary
The Metso D201126 is a DI8 / DI8P digital input module used within Metso Automation (now Valmet) process control and I/O platforms. It is an 8-channel digital input unit that acquires discrete on/off status signals from field devices and passes them to the control system for monitoring, interlocking, and process logic.
Each of its eight input channels handles 24 Vdc PNP-type signals with a 40 mA rating. The module belongs to the Metso D-series board family, alongside boards such as the D201129 DO8 digital output unit and the D201136 processing module, which are commonly maintained together in Metso-based control cabinets. Hardware revisions exist for this part — including Revision 06 and the D201126L variant — so confirming the revision letter/number on the original board’s label against the system configuration is the practical verification step before ordering a replacement spare.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Product type | Digital input unit (PLC / machine control I/O) |
| Module designation | DI8 / DI8P |
| Number of inputs | 8 channels |
| Input signal type | Digital, 24 Vdc, PNP |
| Input current rating | 40 mA |
| Manufacturer / family | Metso Automation (Valmet), D-series I/O boards |
| Known hardware revisions | Revision 05 and Revision 06 units documented; D201126L variant also exists |
| Related family boards | D201129 (DO8 digital output), D201136 (processing/CPU), D201138 (analog input) |
Engineering Selection Highlights
- Exact board identification matters: The D-series uses the base number D201126 with revision identifiers (e.g., Rev. 05, Rev. 06) and an “L” variant (D201126L). The revision on the replacement should match the configuration record of the I/O station it enters, because hardware revisions can carry wiring or firmware differences within the same board family.
- 8-channel PNP input structure: The DI8 designation defines both the channel count and the digital-input function; the PNP (sourcing) input convention determines the field-wiring polarity, which must match the existing marshalling and terminal layout.
- 24 Vdc / 40 mA input level: This is a standard industrial discrete-signal level, compatible with 24 Vdc proximity switches, limit switches, and relay contacts — but field devices must source (not sink) the signal for PNP inputs.
- Paired output board: The D201129 DO8 digital output unit is the complementary board in the same family, so sites maintaining both digital input and output spares typically manage D201126 and D201129 as a pair.
- Spares strategy: As a board-level I/O spare for Metso automation platforms, the practical selection question is slot/rack fit and revision match, not functional equivalence with a generic third-party input module.
D201126
D201126
System Compatibility & Integration Requirements
| Item / Dependency | Verified Compatibility or Requirement | Practical Note |
|---|---|---|
| Control platform | Metso Automation process control / I/O systems using D-series boards | Confirms the module’s family context; system-generation fit should be verified against the site’s controller documentation |
| Input signal | 8 × 24 Vdc PNP digital inputs, 40 mA | Field devices must be compatible with a sourcing 24 Vdc input stage |
| Related boards | D201129 (DO8), D201136, D201138, D201134 within the same D-series module family | Commonly maintained as a group of system spares |
| Revision check | Revisions 05 and 06 documented; D201126L variant exists | Match the revision marking on the original board before ordering |
| Reference marking | Units documented with a TK3343-series reference marking on original labels | Useful as a secondary label cross-check when identifying stock |
Detailed Product Overview
The D201126 is best understood in the context of Metso Automation’s D-series I/O hardware, where a small set of board types covers the digital input, digital output, analog, and processing needs of a distributed control cabinet. The “DI8” designation identifies the board’s function precisely: eight digital input channels on a single unit. For an engineer maintaining one of these systems, the board’s identity is defined by three attributes that must all match — the D201126 order number, the revision marking, and the input convention (24 Vdc PNP, 40 mA per channel).
The PNP input convention deserves attention during panel design and troubleshooting. PNP inputs expect the field device to switch the positive 24 Vdc line to the input terminal, with the common reference at 0 V. Mixing PNP inputs with NPN (sinking) field devices is a classic integration error that produces permanently off or unreliable channels, so when replacing or adding a D201126, the existing field wiring must already conform to the sourcing convention.
Channel capacity of eight inputs per board makes the DI8 a building block for scaling: the number of discrete signals in a cabinet determines how many DI8 boards are populated, and the same rack typically hosts the companion D201129 DO8 board for digital outputs plus analog and processing boards from the same family. For spares planning, this means D201126 failures are usually addressed as board-level swaps rather than field repairs.
Two practical cautions apply to procurement. First, revision control: documented units carry revision markings such as Rev. 05 and Rev. 06, and an “L” variant (D201126L) circulates in the spare-parts market; the revision of the replacement should match what the I/O station and its configuration expect. Second, label cross-checking: original units are documented with a TK3343-series reference marking, which is a useful secondary identifier when verifying stock against a parts list. As with any legacy-platform I/O board, the safest identification procedure is to read the original board’s own label and match all markings exactly.
Applications & System Role
Within a Metso-based automation architecture, the D201126 sits at the digital input interface between field devices and the controller: limit switches, proximity sensors, auxiliary contacts, and status relays deliver binary on/off signals that the module conditions and presents to the control system for state monitoring, interlock logic, and alarm handling. Its engineering role is signal acquisition — converting field discrete states into controller-readable input data.
Typical fit scenarios follow directly from this function: plants that operate Metso/Metso Automation (now Valmet) control platforms in pulp and paper, minerals processing, and power generation maintain DI8-type boards as replacement spares to restore input capacity after a module failure or to support cabinet expansion. It is relevant wherever discrete equipment-status feedback — running/stopped, open/closed, tripped — must reach the controller reliably.
FAQ
What is the Metso D201126?
It is a DI8 / DI8P digital input module from Metso Automation, providing eight digital input channels for process control I/O systems.
What signal type does it accept?
24 Vdc PNP digital signals, with an input current rating of 40 mA per channel.
How many inputs does it have?
Eight digital input channels per module.
Which system does it belong to?
It belongs to the Metso Automation D-series I/O board family, alongside boards such as the D201129 DO8 digital output unit and D201136 processing module.
Are there different revisions of this module?
Yes. Revision 05 and Revision 06 units are documented, and a D201126L variant also exists. Match the revision marking on the original board before ordering a replacement.
Where is it used?
It acquires discrete on/off status signals — equipment running/stopped, valve positions, limit switches, interlock states — and delivers them to the controller for monitoring and logic.
What should I verify before ordering?
The complete order number with revision identifier, the module type (DI8 digital input, not DO8 output), and the label markings on the original board installed in the I/O rack.
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