Description
Key Technical Specifications
The DSAO120AK01 is supplied as a complete functional kit. The internal components and technical parameters match the following breakdown:
| Kit component | Part Number | Description | Quantity |
| Base Output Board | 3BSE018293R1 | DSAO 120A Analog Output Circuit Board | 1 piece |
| Termination Unit | 3BSE018311R1 | DSTA 171 Analog Connection Unit | 1 piece |
| Interconnect Cable | 3BSC950164R30 | DSTK 221L3 Ribbon Cable Assembly | 1 piece |
| Parameter | Value |
| Number of Output Channels | 8 single-ended channels |
| Digital-to-Analog Resolution | 12-bit binary |
| Standard Factory Output Drive | 0 to ±20 mA, 4 to 20 mA, or 0 to ±10 V (Jumper Dependent) |
| Mounting Frame Allocation | Occupies 1 single slot inside an S100 I/O subrack |
| Module Net Weight | 2.0 kg (Full kit assembly weight) |
| Backplane Power Consumption | Draws power directly from standard S100 backplane |
| Galvanic Isolation | Isolated channel-to-backplane via optical couplers |
| Environmental Conformity | Non-RoHS compliant (Exempt via directive Article 2) |
Product Introduction
The ABB DSAO120AK01 (3BSE020419R1) is a high-precision 8-channel, 12-bit analog output module kit designed for the legacy Advant OCS architecture running Master or MOD 300 process control software. Operating within the S100 I/O rack subsystem, this module converts digital commands from the master processor—such as an Advant Controller AC450 or AC460—into accurate current or voltage loops. These hardware lines drive proportional control valves, variable speed motor drives, and analog chart recorders across large-scale continuous processing installations.
This hardware is sold as a fully matched maintenance kit containing the DSAO 120A base processing board, a DSTA 171 field connection unit, and a DSTK 221L3 ribbon interface cable. Plant engineers specify the DSAO120AK01 kit during urgent system restoration to eliminate the risk of sourcing mismatched sub-components or trace ribbons. By isolating the processing electronics from field-side electrical surges through integrated optical isolation paths, this hardware protects your core backplane processing rack from catastrophic damage during hard field grounding faults.
Technical Pitfall & Survival Guide
- The Ribbon Cable Alignment Slip
❗ Risk: Plugging the DSTK 221L3 ribbon cable backwards or misaligning the terminal pins by one row. This error directly shorts the 24V supply distribution traces into the 5V logic paths, frying the internal 12-bit D/A converter immediately on startup.
- Avoidance: The cable connections are keyed, but old plastic clips degrade and break. Inspect the red stripe alignment on the ribbon cable jacket. Ensure it indexes correctly with Pin 1 markings stamped on both the DSAO 120A board and the DSTA 171 termination unit before locking down the frame.
- Component-Level Mixing Errors
❗ Risk: Grabbing a standard standalone board when your controller database expects an assigned “AK01” functional kit profile. Mixing a bare DSAO 120 board with a non-matching, legacy connection unit can alter channel impedance loops and throw scaling calibration out by up to 5%.
- Avoidance: Treat the DSAO120AK01 as a single, indivisible hardware assembly. When executing a replacement swap, always change out the base board, ribbon cable, and connection block together. This guarantees your impedance values match the baseline calibration profile calculated during factory testing.
- Missing Retaining Screw Faults
❗ Risk: Failing to lock down the board using the correct M3x6 Torx screws inside heavy-vibration processing plants. Over time, cabinet resonant frequencies from nearby pumps or mills will walk the S100 board forward out of its backplane guide tracks.
- Avoidance: Every genuine factory kit includes an OEM-spec Torx pan head roll screw (9ADA629-22). Do not leave the slot unbolted or substitute generic field screws that can strip the subrack frames. Secure the module completely to prevent sudden bus disconnection faults down the line. I watched a technician slide a board into a boiler house rack without screwing it down; three months later, nearby fan vibration backed the card out 2 millimeters, causing an instantaneous loop drop that tripped the entire boiler line. Use the screws.
- DSAO120AK01 3BSE020419R1
- DSAO120AK01 3BSE020419R1
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
| All 8 analog loops drop to 0 mA / 0 V | Total loss of S100 rack sub-supply or loose ribbon connection line. | 🟡 Medium | Check if adjacent modules are processing data. Verify the DSTK 221L3 ribbon cable is fully seated in its sockets. | If adjacent cards are green, shut down the rack segment and re-seat the interconnecting ribbon cable before replacing hardware. |
| A single valve positioner fluctuates erratically | External field loop grounding fault or failed 12-bit converter channel. | ✅ High | Lift the field wires from the DSTA 171 block. Connect a dummy precision resistor across the terminals and measure the drop voltage with a multimeter. | If the voltage stabilizes across the test resistor, your field wiring or valve positioner has a grounding issue. If it stays erratic, replace the kit. |
| PLC logs throw a “Module Mismatch” or Bus Error | Board ID jumper settings or firmware tracking mismatch in the AC450 database. | ✅ High | Compare the physical revision level stamped on the 3BSE018293R1 board face with your active system engineering documentation. | Verify the system block configuration constants in your Master software platform match this exact revision tier before restarting the slot. |
| Outputs saturate to max value continuously | Open circuit down the loop or blown channel output protection diode. | 🟡 Medium | Check the total series resistance of the loop with an ohmmeter. Ensure it does not exceed the maximum load specification. | If loop resistance is correct but the output remains locked at full scale despite soft-override commands, the internal driver transistor is failed short. |
Frequently Asked Questions (FAQ)
Why is this hardware sold as a complete “AK01” kit instead of a simple standalone circuit card?
ABB configured the part number as a complete kit to simplify maintenance logistics for plant operators. If you only replace the internal circuit board, a degraded termination card or a worn ribbon cable can still transfer noise and cause intermittent processing trips. Replacing all three synchronized sub-components at the same time ensures the entire loop matches original design tolerances.
Can I hot-swap this kit while the Advant Controller AC450 is online and processing?
Absolutely not. The S100 I/O rack infrastructure does not feature isolated hot-swap backplane switches for this component class. Removing the board while the rack backplane is energized can induce a localized voltage drop across the shared data lines, causing adjacent processing cards to drop offline and triggering an emergency shutdown of the entire controller rack.
Are the configuration jumpers on the 3BSE018293R1 board set for current or voltage loops by default?
Our New Surplus kits ship in factory-clear defaults, which are typically jumpered for standard current loops (such as 4 to 20 mA). You must trace and compare the hardware jumper configuration arrays on your old board and replicate those settings exactly on the new card before mounting it inside the live subrack.
What does the “Non-RoHS Compliant” status mean for my facility’s procurement policies?
Because this is a legacy system component designed strictly for heavy industrial control networks (specifically Advant OCS platforms), it falls under specific industrial exemption clauses regarding leaded soldering alloys. This status does not impact safety or operation, but it means the kit cannot be used in consumer-facing or standard commercial facilities requiring strict RoHS-5 or RoHS-6 declarations.
Can I use this kit if my existing system utilizes MOD 300 software rather than Master software?
Yes. The hardware kit interfaces directly with the hardware-level I/O rack bus, meaning it is compatible with both Advant OCS with Master software and Advant OCS with MOD 300 software setups. The underlying physical signal processing functions exactly the same way regardless of the top-level software package used.
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