ABB TB521-ETH

ABB TB521-ETH

Product Brief:​ The TB521-ETH is the foundation termination unit (TU)​ onto which S800 I/O modules (DI830, DO820, AI835, AO845, etc.) are snapped in a DIN-rail mounted S800 I/O rack. It provides:

  • Mechanical guide rails & end-stop for up to 12 S800 I/O modules (or more with daisy-chained TUs)
  • Electrical bus bars (5 V logic, 24 V process UP, PE) connecting all modules on the rack
  • Terminal blocks or headers for 24 V DC input power (to PPD113A01 power module which typically mounts on left end of TU stack)
  • Mounting holes / DIN clips for the HN800 bus interface module (CI840A / CI841) and for the power supply module (PPD113)
  • Integrated PE (protective earth) busbar with multiple earthing points
  • The “-ETH” version includes RJ45 cutouts / tie-points for Ethernet cabling management and improved EMC grounding features vs. base TB511

    It does not​ contain electronics — it is the passive mechanical/electrical backbone. The active intelligence comes from the I/O modules + CI840A (for remote I/O) or from direct ModuleBus connection to an AC 800M CPU baseplate (for local I/O).

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Category: SKU: ABB TB521-ETH

Description

ABB TB521-ETH

  • Technical Specifications:
    • Compatible I/O Modules: All S800 I/O (DI8xx, DO8xx, AI8xx, AO8xx, DP8xx, TP8xx…) — max 12 modules per TB521 (some high-density or special modules may limit to fewer — check total 5 V current budget)
    • ModuleBus: Connects to AC 800M CPU baseplate (BC810/BC820) via flat ribbon cable (TK801V006etc.) for local I/O; OR connects to CI840A (mounted on TB521) for remote I/O (HN800 bus)
    • Power Connections: Accepts 24 V DC from plant PSU → PPD113A01 (mounts on left of TB521) → distributes 5 V logic & UP to modules
    • DIN Rail: 35 mm (EN 60715) — top & bottom DIN clips on TB521
    • Dimensions (TB521 alone): ≈45 mm (W, per module slot) × 119 mm (H) × 102 mm (D) — actual width = 45 mm × (1 + #modules) when populated
    • Material: Glass-fiber reinforced polyamide (PA66), UL 94 V-0; nickel-plated brass PE bar
    • Operating Temp.: –20 °C to +55 °C (same as S800 modules)
    • Certifications: CE, UL, cUL, ATEX Zone 2 (with system cert), marine (DNV/ABS/LR)
    • Max 5 V Logic Current (total rack): Typically ≤3 A (depends on PPD113 version — PPD113A01 provides up to 3 A 5 V)
  • Functional Features:
    • Hot-swappable I/O modules (with controller scan support)
    • Keyed end-plate prevents mismating of different S800 generations (S800 vs S900 — different key)
    • Integrated strain relief for bus cable & power cables
    • Grounding bar ensures star-point earthing of all modules’ PE connections
  • Application Scenarios:
    • Forms the base of every S800 I/O rack — local (direct ModuleBus to AC 800M) or remote (CI840A + HN800)
    • Used in System 800xA, Freelance (with AC 800M PM9xxF + CI840A), and Advant OCS migration (CI520A + S100→S800 retrofit)
    • -ETH preferred in Ethernet-rich panels for better cable management of RJ45 from CI840A
  • Material & Structure:
    • Molded glass-filled nylon base with integral aluminum or brass PE busbar
    • Spring-steel DIN clips (top & bottom)
    • Printed circuit bus bars (5 V, 24 V UP, AGND) embedded in molding — gold-plated contacts mate with module edge-fingers
    • End plates (left & right) — one for PPD113 side, one for last I/O module — keyed
  • Working Principle:

    When an module is snapped into , its gold-edge connector mates with the embedded bus bars → 5 V logic, 24 V process (UP), and PE are immediately available. The CI840A(if present) communicates with modules via the ModuleBus lines on the backplane. For local I/O, a TK801V006 flat cable links the ModuleBus header to the AC 800M CPU baseplate’s ModuleBus header — the CPU directly scans I/O images each cycle.

  • Installation Requirements:
    1. Mount -ETH on 35 mm DIN rail — ensure DIN clips engage; leave ≥50 mm top/bottom for ventilation & cable bending
    2. Snap in PPD113A01 power module (leftmost position) → connect 24 V DC incoming power (A/B redundant if used) to PPD terminals → verify 5 V OK LED on PPD
    3. Snap in I/O modules (DI830, DO820, AI835…) into subsequent slots — they self-seat on bus bars
    4. Install CI840A(if remote I/O) onto its DIN clip / header on or into CEX slot on AC 800M baseplate (for local I/O no needed — just ModuleBus cable)
    5. For local I/O: connect TK801V006 ModuleBus cable between ModuleBus header & AC 800M CPU baseplate ModuleBus header
    6. For remote I/O: connect HN800 fiber/copper from to upstream switch / controller
    7. Wire field signals to I/O module terminals per channel assignment
    8. In Control Builder M / Freelance: define I/O station → assign module types → download → verify Com LED on (remote) or Run LED on CPU (local)
    9. Terminate HN800 bus with 120 Ω resistor (built-in jumper on CI840Aor external) at both ends
  • Precautions:
    • ESD:​ Although modules are hot-swappable, handle by edges; touch DIN rail / cabinet earth before touching module edge-connector
    • Ensure 24 V DC supply polarity correct & fused (typical 2–5 A slow-blow per PSU)
    • Do NOT exceed total 5 V current draw of rack — sum module logic currents (typ. 80–150 mA/module) ≤ PPD113 5 V rating (3 A typical) — if close to limit consider splitting into two racks / using PPD115 (higher current)
    • Verify module keying matches ( modules have key on bottom — has corresponding notch; S900 won’t fit)
    • Always terminate HN800 / ModuleBus at both ends — missing termination = CRC errors / intermittent dropouts

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