Honeywell MU-PDIY22 – 24 VDC Digital Input/Pulse Module for Experion TPS / PM/IO

The Honeywell MU-PDIY22 is a discrete input module designed for Honeywell TPS and PM/IO architectures. From my experience, it’s the card you pick when you need dependable 24 VDC digital status monitoring with pulse-capture capability on mature Experion TPS systems. Typical applications include reading dry contacts and open-collector sensors, turbine flow meter pulses, proximity switches, and general on/off equipment states in process plants.

Order Placement Process and Guarantees

• Warranty: 365 days
• Lead time: 1 week if in stock; no more than one month at the latest
• Payment: 50% advance payment, full payment prior to delivery
• Shipping: FedEx, UPS, DHL
• Pre-shipment checks: Visual inspection, basic functional screening, and packaging to ESD/industrial standards

Key Features

• 24 VDC discrete inputs (typical): Suited for standard plant wetting voltage; reads dry contacts and transistor outputs.
• Pulse capture capability: Handles pulse/frequency inputs commonly used with flow and speed pickups in many cases.
• Backplane integration: Communicates over the Honeywell PM/IO/TPS backplane; no external comms wiring needed.
• Field wiring via FTA/IOTA: Compatible with Honeywell termination assemblies to keep cabinet wiring straightforward and serviceable.
• Designed for process duty: Stable performance across typical control room temperatures with robust isolation practices.
• Lifecycle continuity: Good choice for sustaining legacy TPS I/O while keeping loop re-termination to a minimum.

Technical Specifications

Where it fits — typical scenarios

You might notice that MU-PDIY22 tends to show up in utilities and heavy process units where reliable status and pulse counts matter: boiler house equipment interlocks, loading stations with totalizers, compressor panel contacts, or tank farm instruments with proximity switches. One thing I appreciate is the way it slots into existing Honeywell cabinets with minimal rewiring, especially when you already have the right termination assemblies in place.

A maintenance engineer at a metals plant told us the card “seems to be the least fussy with our mixed contact sources,” after they had to tie in several vendor skids that delivered a mix of dry contacts and NPN pulse outputs. That’s typical in retrofit jobs.

Related or Supporting Products

• Honeywell MU-PDOY22 – Discrete Output module, 24 VDC typical; pairs with MU-PDIY22 when you need both status in and command out.
• Honeywell MU-TAIH04 – Analog Input module; for process signals (4–20 mA, typical) alongside your discrete counts.
• Honeywell MU-TAOY22 – Analog Output module; often used for control valve or speed reference outputs in the same rack.
• Honeywell FTA/IOTA assemblies – Field termination hardware for clean panel wiring, fuse options, and channel isolation (model varies by enclosure and wiring style).
• Honeywell CC-TDIL01 – For C300/Series 8 systems, a comparable DI function module; not plug-compatible with MU-series but often considered during phased upgrades.

Installation & Maintenance

• Cabinet environment: Install in a clean, ventilated control cabinet; maintain clearance for airflow per Honeywell rack guidelines.
• Wiring practices: Use the recommended FTA/IOTA; separate low-level signal and power wiring; observe polarity for 24 VDC wetting.
• Shielding & grounding: Bond shields at the designated terminal; avoid ground loops especially on long pulse lines.
• Safety: De-energize field circuits before module insertion/removal; follow ESD precautions when handling the card.
• Routine checks: Verify input status and pulse counts during PM rounds; inspect terminal tightness and fuses on the FTA annually.
• Firmware/configuration: Back up controller configuration; apply Honeywell-recommended updates and note any module revision nuances.
• Calibration: Not normally required for DI; periodic functional testing (contact simulate/pulse injection) is typically sufficient.

Quality & Certifications

• CE marking for industrial control environments (EMC and LVD, per Honeywell documentation)
• UL/cUL recognition for control equipment (typical for Honeywell TPS/PMIO modules)
• RoHS status varies by revision; many later revisions are RoHS compliant
• Manufacturer’s standard warranty honored; our supply warranty is 365 days as stated above