ABB DSQC 633A SMB Unit 3HAC031851-001 for IRB 6600 Series

Serial Measurement Board Unit — Technical Overview

This is the measurement hub on the robot, not a board in the controller cabinet. Each axis of the manipulator carries a measurement device, and this unit collects that position data and passes it back to the controller over a serial link. ABB lists it under its robot categories rather than its controller categories, and it is catalogued as a spare part for a defined set of IRB models.

Specifications

Industrial Applications

• IRB 6600, IRB 6650, IRB 6650S and IRB 7600 — the heavy payload robots of the M2004 generation, where ABB records this unit as a spare part across Type A, Type B and Foundry Prime variants.
• IRB 460, IRB 1410, IRB 1600 and IRB 1660ID — the mid-range and process robots listed under the same unit.
• IRB 1520ID — listed both in the categories and as a used-on reference for this part number.
• Scheduled battery and counter service — the SMB is tied to the backup that keeps revolution counter data alive, so it commonly comes up when a robot starts losing its position reference.
• Collision repair and robot refurbishment — replaced when the measurement chain has been disturbed or the unit has been damaged.
• Not for paint robots — those use the separate article noted above.

Design Purpose

Running individual measurement wiring from every joint back to the controller would mean a thick, noise-prone harness following the manipulator through every axis. The SMB avoids that: the measurement devices terminate on this unit at the robot, and one serial link carries the position data to the controller. It is a consolidation point, and it is why a fault here is reported as a measurement or communication problem rather than as a motor or drive problem.

The other consequence is that this unit is tied to the robot's calibration identity. It is associated with the backup that keeps revolution counter data alive while the controller is powered down, which is what lets the robot know where it is without being re-referenced at every start. That is why replacing an SMB is not purely a mechanical swap: the revolution counters normally have to be checked afterwards and the robot referenced before it goes back into production. It is also why the replacement route goes through configuration-specific sets rather than one universal part number.

Common Failure Modes

Symptoms that typically lead to an SMB being checked or replaced:

• Robot loses its position reference — it asks to be re-referenced, or the counter data is reported as not updated.
• Counter data lost after the controller has been powered down — usually retention rather than the board itself.
• Communication fault on the measurement link — the controller reports it cannot exchange data with the measurement unit.
• No position data from one or more axes, or a single axis that will not hold its reference.
• Intermittent position errors or unexpected axis movement — often a connection or harness issue at the unit rather than the board.
• Moisture, oil or corrosion inside the SMB enclosure — a common finding on Foundry and washdown-duty machines.
• Damaged connector, seal or cable entry after a collision or after the manipulator has been worked on.

Why Choose Us

• Genuine ABB part, supplied against part number 3HAC031851-001.
• Part number, robot model and robot type checked with you before dispatch, including the Type A / Type B and Foundry Prime distinctions.
• Help choosing the right route: this unit, the applicable 3HAC046686 replacement set, or the separate paint-system article — three different answers depending on your machine.
• New original or used original available — the condition is confirmed with you before you order.
• Photos and label details of the actual unit provided on request, so you can compare the connector layout and identifier against your existing unit.
• Guidance on the backup and referencing steps that follow an SMB replacement.
• Sealed in anti-static packing with rigid support for transit; ships worldwide from Shanghai.
• PayPal, T/T bank transfer and Alibaba Trade Assurance accepted.

Related Products

• 3HNA006142-001 — the article ABB specifies for PAINT systems. If your controller is recorded as a paint system, this is the one you need rather than 3HAC031851-001.
• 3HAC046686-001 — SMB replacement set. Note there are four variants (-001, -002, -003, -004) selected by the installed robot, battery contact variant, enclosure and cable set; check which your machine takes.
• 3HAC028357-001 — DSQC 679 FlexPendant, used to reference and check the robot after SMB work.
• 3HAC025097-001 — DSQC 639 Main Computer for IRC5 controllers.
• 3HAC029818-001 — DSQC 663 Main Drive Unit for the IRC5 drive system.