Configured for MA200 bus bridging between an Advant Master engineering station PC and the controller rack, the ABB DSPU131 3BSE000355R1 (DSPU131 MA200 Interface Board) provides direct AT-bus physical-layer translation and DSP-assisted packet routing.

Part Number and Variant Notes

DSPU131 is the base board type, 3BSE000355R1 the ABB order/serial prefix. Market labels also read "DSPU 131 MA200 Interface Board". This is not a DSSR/DSSA power or I/O card; it seats in the engineering-station ISA/AT slot or the dedicated MasterAid 200 interface bay, not in a standard S100 I/O rack. No "-EL/-NK" country suffix is printed on the board itself; Sweden is the declared origin per ABB tariff data. Do not confuse with DSPC131 (communication processor) or DSSR131 (relay supply).

Hardware Specifications

AT-bus to MA200 Bridge and Backplane Bus Behavior

DSPU131 carries a 32-bit DSP that terminates the engineering-station AT-bus (ISA 16-bit electrical, 8 MHz host clock) on one edge and the MA200 differential link on the other. The DSP firmware (resident in 512 KB Flash, booted into 256 KB RAM) performs MA200 frame assembly, node addressing, and CRC validation; it does not execute IEC 61131 logic and does not drive S100 I/O cards directly. Backplane bus communication velocity on MA200 is fixed by the Advant Master SW cycle (typically 10-50 ms token window); the DSP adds no negotiable latency beyond its 200 MHz instruction pipeline. Firmware flash compatibility is bound to MasterAid 200 / PG200 toolchain — a DSPU131 burned with AC450-only image will not enumerate on a MasterPiece 200 engineering station and vice versa. Hot-swap is not supported on the AT-bus side (ISA spec forbids live extraction); on the MA200 side the link recovers in roughly 2-3 s after reconnect but the engineering session must re-bind.

Ordering Info

• 1 x DSPU131 3BSE000355R1 PCB with AT-edge connector and MA200 front D-sub
• 1 x printed Sweden-origin label with 3BSE000355R1 barcode
• 1 x RoHS exemption sticker (Art 2(4))
• 2 x mounting bracket screws pre-fitted
• No ribbon cable, no MA200 terminator, no PG200 software media included

Installation and Bus Bonding

• Seat in a free 16-bit ISA slot of the Advant engineering station; 8-bit slot yields AT-bus decode fault and ACT LED never blinks.
• Terminate MA200 link with 120 ohm at the furthest node; DSPU131 itself is mid-bus, not terminator.
• Bond AT-bus chassis ground to controller rack 24 VDC field ground at single point in cabinet; do not loop shield through DSPU131 metal bracket.
• Keep MA200 coax/paired run away from 24 VDC power trays by 50 mm minimum to suppress ARCnet-era reflection noise.
• Never extract under AT-bus power; ISA gold fingers arc and can latch the host PC southbridge.

Frequently Asked Questions

Does DSPU131 execute control logic for AC450?

No. It only bridges MA200 frames between engineering station and controller rack. All IEC 61131 code runs on PM630/AC450 CPU; DSPU131 DSP handles protocol packing, not process scanning.

What power does the board draw from the PC?

+5 VDC 1.6 A dominant, plus +12 VDC 25 mA and -12 VDC 25 mA for MA200 transceiver bias. Total 8.5 W from AT-bus edge. A weak PC power supply under 200 W will brown out the board.

Can firmware be reflashed with modern Composer?

No. 3BSE000355R1 Flash image is bound to MasterAid 200 / PG200 DOS-Windows 2000 era toolchain. Composer 5.x does not push DSPU131 images; use the legacy ABB PGM132 burn utility on a segregated engineering laptop.

Is MA200 link galvanically isolated from AT-bus?

Yes. Opto-decouplers on the MA200 transceiver side provide 1000 VDC isolation. A ground fault on plant bus does not back-feed the engineering station motherboard, but the AT-edge ground still shares PC chassis.

Why does ACT LED stay dark after boot?

Either ISA slot is 8-bit only, or MA200 cable is unterminated/open. Check 120 ohm terminator at far node, verify +5 VDC on AT-bus pin 29-30, and confirm DSPU131 enumerates in PG200 hardware scan.

Can two DSPU131 share one engineering station?

Yes, on separate ISA slots with distinct MA200 node IDs, but MasterAid 200 license historically binds one active MA200 session per board. Second board acts as passive sniffer unless re-addressed in registry.

What replaces DSPU131 in modern AC 800M retrofits?

Nothing pin-compatible. Migration uses OPC DA server on a PC plus CEX bus, dropping MA200 entirely. DSPU131 stays mandatory only for legacy Advant Master / MasterPiece 200 online maintenance.

What is the mechanical envelope for rack clearance?

Board is 334.6 mm x 121.9 mm x 21 mm typical (shipping box 20 x 350 x 128 mm). Needs 1 full ISA slot height plus 10 mm rear clearance for MA200 D-sub; does not fit low-profile SFF PCs.