Introduction
In the history of distributed control systems (DCS), the Honeywell TDC 3000 series is undoubtedly a milestone. The enhanced Micro TDC 3000 8-node system (model MT11-520) released in 1995 is the most compact yet fully functional member of this classic family. It compresses the core capabilities of TDC 3000X, including Universal Station (US), Application Module (AM), Network Interface Module (NIM), History Module (HM), and Advanced Process Manager (APM), into two standard cabinets (towers) and achieves inter node communication through a high-speed twisted pair local control network (TPLCN). This article is based on the official 8-Node Enhanced Micro TDC 3000 User's Manual, which fully restores the technical details of this legendary system from six dimensions: hardware composition, communication protocol, installation and wiring, system implementation, operation and maintenance, and spare parts support.
System Overview and Model Differences
The enhanced Micro TDC 3000 offers two basic models:
MX-DTAB01K2: Includes K2LCN processor, 1 Universal Station (US), 1 Advanced Process Manager (APM), 4 MW Memory Application Module (AM), 875 MB Hard Disk History Module (HM).
MX-DTAC01K2: Except for upgrading AM memory to 8 MW, everything else remains the same as before.
In the early days, "version B" was equipped with two US nodes, but after the R500 software version, "version A" became the only basic configuration, and the second US became an optional node. All nodes are equipped with K2LCN processor boards, and the US comes standard with 6 MW of memory and supports "Universal Personality", which can be switched between the operator and engineer interfaces with just one click. The system no longer supports UXS or AXM expansion, but can be connected to standard LCN networks through the LCN upgrade kit.
Hardware architecture: Twin tower four node and Multinode module
The electronic core of the entire system is installed in two cabinets (towers) with similar appearances. Tower 1 (right side) accommodates nodes 1-4, including US, AM, NIM, and optional third/fourth US; Tower 2 (left side) accommodates nodes 5-8, including HM, second US, redundant NIM, and optional computer gateway (CG) or enhanced PLC gateway (EPLCG). Each tower is equipped with a Multinode module, which adopts a 3/3/2/2 backplane layout and can accommodate up to 4 nodes. Each node consists of two circuit boards: K2LCN processor board and corresponding peripheral/personality board.
In terms of peripheral devices:
Display: Available in 20 inch or 21 inch color CRT, supports IDEK MF-5221 (analog knob), IDEK MF-8221 (digital buttons), and HITACHI HM-4821-D (CE certified) models.
Keyboard: Flat membrane operator keyboard with built-in three tone speakers and 16 user programmable keys on the left side; The engineer keyboard adopts a PC-AT layout and supports hot plugging during system operation.
Pointing device: Infrared touch screen or trackball (optional), sharing the J1 interface on the EPDGP I/O card.
Storage: US standard dual 150 MB Bernoulli cartridge drives (compatible with 35 MB media); HM has a built-in 875MB 5.25-inch SCSI hard drive (WREN III or subsequent 512 MB models).
Printer: ASPI-41 dot matrix printer, connected to US via Centronics interface.
Communication Network: TPLCN and LCN Upgrade
The nodes inside and between towers are interconnected through TPLCN (twisted pair local control network). This network is based on the RS-485 electrical standard, with a transmission rate of 5 Mbps. It uses the same token passing protocol as the standard LCN, but eliminates coaxial cables and transceivers to accommodate short distance cabinet layouts. The TPLCN cable uses Honeywell's specialized shielded twisted pair cable (part number 51304505-100, standard 1.5 meters; optional 10 meters), connected through the tower's TP485 card (slots 1 and 9).
When integrating Micro TDC 3000 into larger standard LCN systems, the LCN upgrade kit can be used. The kit includes LCN cabinets, 5/7 slot empty chassis, fans/power supplies, coaxial cables, and WDA modules. At this point, except for the US node, all other nodes need to be migrated to independent modules in the LCN cabinet. The HM hard drive is moved into the WDA, and the TPLCN is replaced by a coaxial LCN. After the upgrade, the system can seamlessly collaborate with other LCN devices such as computing modules, historical modules, etc.
Installation and Wiring: From Site Preparation to EMC Compliance
Environmental requirements: The system is designed for Class C (office) environments, with an operating temperature of 0-45 ° C, a storage temperature of -10-70 ° C, a relative humidity of 10-80%, no condensation, vibration tolerance of 5-22Hz 0.254mm displacement, and 22-500Hz 0.25g. Tower dimensions: height 72cm, width 32cm, depth 58cm, with a single tower weight of approximately 45kg; APM cabinet (double-sided channel) height 210cm, width 80cm, depth 80cm, weight 200kg.
Power supply: Supports 120/240 Vac (+10%/-15%), frequency 47-63 Hz. Tower 1 is fully loaded (1 US+AM+NM+driver) with a typical current of 1.65A and power consumption of about 102W; Tower 2 (HM only) has a typical current of 1.15A and power consumption of about 56W. Each tower requires an independent NEMA 5-15R socket, and international models are equipped with CEE-7 plugs. Surge current limit is 15A@120V .