Description:
The Honeywell 620-0027 is a UCN (Universal Control Network) memory module for Honeywell’s TDC 3000 and TPS distributed control systems — a battery-backed SRAM daughter board that plugs into the main processor card of UCN nodes such as the High-Performance Process Manager (HPM), Advanced Process Manager (APM) and History Gateway (HG). It is not a controller; it is the controller’s memory, holding firmware, control strategy configuration, point database and runtime parameters so the node survives a power cycle without a host download.
That distinction matters more than it sounds. In a TDC 3000 architecture the 620-0027 is what makes each process manager an autonomous unit rather than a terminal on a network. Lose it, or let its battery die, and the node does not degrade gracefully — it forgets.
Application Scenarios:
A refinery’s fluid catalytic cracking unit runs on a TDC 3000 system commissioned in the early 1990s, with six HPMs on the UCN carrying the reactor-regenerator controls, the main fractionator and the wet gas compressor. The plant has a validated control strategy that has been tuned over three decades, and the engineers who wrote the CL/PM point configuration retired some years ago. The real risk is not a CPU failure — spare HPMs exist — the risk is a 620-0027 with a lithium cell that has quietly passed the end of its useful life. One extended outage, one brownout long enough to drain the backup, and the point database is gone.
That is the scenario this module was designed to prevent, and also the scenario that defines how it has to be managed. Because the data lives in battery-backed SRAM on the card, the maintenance question is never “will it fail” but “when does the cell reach end of life”, and the answer is a function of cabinet temperature more than calendar time.
A second context is migration staging. Plants moving from TDC 3000 to Experion PKS often keep the UCN alive underneath for years while process units are cut over one at a time. During that window the 620-0027 stops being a legacy curiosity and becomes a scheduled consumable: every node still running on UCN is dependent on a card that Honeywell no longer manufactures.
Parameter:
| Main Parameters | Value / Description |
|---|---|
| Product Model | 620-0027 |
| Manufacturer | Honeywell (Honeywell Process Solutions) |
| Product Category | UCN memory module / non-volatile memory expansion daughter board |
| Series | TDC 3000, TPS — Universal Control Network (UCN) |
| Target Hardware | UCN nodes: HPM, APM, HG (History Gateway), HLA, NIM and AM UCN port cards — verify against node hardware revision |
| Memory Technology | Static RAM (SRAM) with on-board lithium backup cell |
| Storage Capacity | Commonly quoted as 1 MB; 512 KB and 256 KB figures also appear in reseller data — confirm against the physical board label |
| Data Retention | Battery-backed; Li-SOCl₂ cell, ~3.6 V, typically 5–10 years at 25 °C, materially shorter at sustained high cabinet temperature |
| Function | Retains controller firmware, control strategy, point database, tuning parameters and historical buffer without external power |
| Power Supply | +5 V DC drawn from the host processor board through the backplane connector |
| Configuration | On-board jumpers set memory address range and capacity mapping |
| Mounting | Plug-in daughter board, seats into a dedicated socket/slot on the controller’s CPU card (e.g. MFCD) |
| Form Factor | Proprietary PCB with edge connector, roughly full-length card profile |
| Dimensions | Listings cite either ~245 × 160 × 30 mm or ~150 × 110 × 25 mm — treat the board label as authoritative |
| Weight | Approximately 0.36 kg (some listings state 0.68 kg) |
| Operating Temperature | 0 … +60 °C controller internal environment (industrial-grade variants quoted to +70 °C) |
| Storage Temperature | −25 … +85 °C typical |
| Humidity | 5–95 % RH, non-condensing |
| Lifecycle Status | Discontinued by Honeywell; supplied as new-surplus, NOS or professionally remanufactured stock |