Product Core Brief

• Model: DSTD108
• Order Code: 57160001-ABD
• Brand: ABB
• Series: ABB Advant OCS / Advant S100 I/O
• Core Function: 8-channel relay output connection unit for the Advant OCS / S100 I/O system — provides relay-based switching and signal conditioning for digital output applications in industrial automation.
• Product Type: Connection Unit (Relay Output)
• Key Specs: 8 relay channels | 24 VDC input control | 24–250 VAC/VDC output switching | Max load current 3 A | Min load current 0.1 A at 24 V
• Condition: New Original / New Surplus

Key Technical Specifications

• Product Type: Connection Unit for ABB Advant OCS / S100 I/O System
• Brand: ABB
• Model Number:
• Order Code: 57160001-ABD
• Series: ABB Advant OCS / Advant S100 I/O
• Core Function: Provides relay-based digital output switching for the Advant OCS / S100 I/O system — acts as the interface between the controller’s digital output signals and field devices such as contactors, solenoid valves, indicator lights, and motor starters
• Number of Channels: 8 independent relay output channels
• Control Input: 24 VDC — receives control signals from the Advant OCS / S100 digital output module
• Output Switching Range: 24–250 VAC/VDC — supports both AC and DC load switching, providing flexibility across different field device requirements
• Load Current: Maximum 3 A per channel | Minimum 0.1 A at 24 V — suitable for switching low-power signal devices as well as moderate-power actuators
• Relay Type: Electromechanical relay — provides galvanic isolation between control circuit and load circuit, protecting the controller from voltage spikes and transients on the load side
• Mounting Method: Modular plug-in design for Advant S100 I/O rack — enables straightforward like-for-like replacement during maintenance
• Environmental Rating: Designed for industrial control cabinet installation
• Product Status: Discontinued (spare parts supply) — compatible with ABB Advant OCS / S100 I/O ecosystems
• Typical Applications: Relay output interfacing for ABB Advant OCS-controlled industrial automation systems — switching contactors, solenoid valves, indicator lights, motor starters, and alarm devices in process control, manufacturing, and power generation applications; serving as a critical spare part for lifecycle support of mature Advant OCS installations where relay output connection unit replacement is required

 

Product Introduction

The ABB DSTD108 (order code 57160001-ABD) is an 8-channel relay output connection unit designed for the ABB Advant OCS / S100 I/O system, engineered to provide reliable relay-based switching between the controller’s digital output signals and field devices in industrial automation applications. In a typical Advant OCS installation, the DSTD108 serves as the critical interface layer — it receives low-voltage 24 VDC control signals from the digital output module and uses its internal electromechanical relays to switch higher-voltage AC or DC loads, such as contactors, solenoid valves, indicator lights, and motor starters.

What distinguishes the DSTD108 from simple terminal blocks is its integrated relay functionality. Each of the 8 channels contains an independent electromechanical relay that provides galvanic isolation between the control circuit (24 VDC from the controller) and the load circuit (24–250 VAC/VDC field devices). This isolation is essential for protecting the sensitive controller electronics from voltage spikes, transients, and electrical noise that are common on industrial load circuits — especially when switching inductive loads like contactors and solenoid valves.

The relay’s switching range of 24–250 VAC/VDC provides significant flexibility. A single DSTD108 can simultaneously control AC-powered devices (such as 110 VAC or 220 VAC contactors) and DC-powered devices (such as 24 VDC solenoid valves or 48 VDC alarm circuits) without requiring separate connection units. The maximum load current of 3 A per channel is sufficient for most industrial control applications, while the minimum load current specification of 0.1 A at 24 V ensures reliable switching even for low-power signal devices.

For system integrators and maintenance engineers supporting mature Advant OCS installations, the DSTD108 is a critical spare part. As a discontinued product, availability of genuine units is essential for lifecycle support — a failed relay connection unit can prevent the controller from switching multiple field devices simultaneously, potentially disrupting process control, safety interlocks, or equipment operation. Having verified genuine DSTD108 units on hand ensures that relay output failures can be resolved quickly, keeping production running.

QA & Testing SOP

Every unit undergoes a standardized verification process before shipment:

• Visual & Anti-Counterfeit Check: Inspect the unit housing for proper ABB branding and part number marking (DSTD108, 57160001-ABD). Check for physical damage including cracked housing, damaged connector pins, burnt relay components, or signs of moisture ingress (corrosion, white residue on contacts).
• Connector Pin Inspection: Examine all connector pins (control input terminals, load output terminals, backplane interface) for straightness, corrosion, or bending. Damaged pins can cause intermittent connections or switching failures.
• Relay Coil Test: Apply 24 VDC control signal to each channel and verify that the relay coil energizes correctly — listen for the characteristic click and measure coil current to confirm proper operation.
• Contact Continuity Test: With relay energized, verify that the output contacts close with low resistance (< 100 mΩ). With relay de-energized, verify that contacts open with high isolation resistance (> 10 MΩ). This ensures reliable switching and proper galvanic isolation.
• Load Current Test: Apply rated load current (up to 3 A) to each channel and verify that the relay contacts can carry the current without excessive voltage drop or heating. This confirms that the relay can handle the specified load without premature contact wear.
• Minimum Load Test: Verify that each channel can reliably switch the minimum specified load of 0.1 A at 24 V — this ensures compatibility with low-power signal devices.
• Galvanic Isolation Test: Verify that there is proper electrical isolation between the control input circuit (24 VDC side) and the load output circuit (24–250 VAC/VDC side) — this protects the controller from voltage spikes on the load side.
• Backplane Communication Test: Insert the unit into an Advant S100 I/O rack and verify that the controller recognizes the DSTD108 correctly with no communication errors.
• Anti-Static & Mechanical Protection: After passing all tests, the unit is placed in anti-static shielding with protective caps on connectors. It is then packed in rigid cardboard with foam cushioning to prevent mechanical shock and ESD damage during transit.

Installation Pitfalls & Guide

Real-World Risks When Replacing This Unit:

❗ System Compatibility: The DSTD108 is designed exclusively for the ABB Advant OCS / S100 I/O system. It is not compatible with other ABB controller families such as AC 800M, IRC5 robot controllers, or Symphony Harmony systems, which use different I/O architectures. Always verify your controller model before ordering.

❗ Load Current Rating: Each channel is rated for a maximum of 3 A. If your application requires switching loads exceeding 3 A, you must use an external contactor or relay — do not exceed the rated current, as this will cause premature relay contact wear or failure.

❗ Inductive Load Protection: When switching inductive loads (contactors, solenoid valves, motor starters), voltage spikes can occur when the relay opens. Ensure that appropriate snubber circuits or flyback diodes are installed on the load side to protect the relay contacts from arc damage.

❗ Minimum Load Requirement: The relay requires a minimum load current of 0.1 A at 24 V for reliable switching. If your load current is below this threshold, the relay contacts may not make reliable contact, leading to intermittent operation. Consider using a wetting current circuit or a different output type for very low-power loads.

❗ AC vs DC Load Wiring: The DSTD108 supports both AC and DC load switching, but the wiring must be correct for each type. Verify that AC loads are connected to the correct terminals and that DC loads observe proper polarity where required.

❗ Incorrect Slot Placement: The DSTD108 must be installed in the correct Advant S100 I/O rack slot position as specified in the controller’s I/O configuration. Installing it in the wrong slot can prevent the controller from recognizing the unit, resulting in output switching failures. Always verify the slot assignment matches the system documentation before insertion.

❗ Power-Down Requirement: Always power down the Advant OCS controller before inserting or removing connection units. Handling units while the system is powered can cause electrical damage to the unit or controller.

4-Step Replacement Guide:

1. Pre-Install: Identify the failed DSTD108 slot position in the Advant S100 I/O rack. Document the existing channel configuration and connected load devices from the system documentation. Back up the current controller configuration. Power down the Advant OCS controller and disconnect the main power supply.
2. Removal: Disconnect all control input and load output wiring from the DSTD108 terminal block. Release the unit locking mechanism and carefully slide the old unit out of the rack slot. Inspect the backplane connector and wiring for damage or debris.
3. Install: Insert the new DSTD108 unit into the correct rack slot, ensuring proper alignment with the backplane connector. Secure the unit with the locking mechanism. Reconnect all control input wiring (24 VDC from the digital output module) and load output wiring (to field devices), verifying correct terminal assignments and that connectors are fully seated.
4. Power-On Test: Reconnect the main power supply and power up the Advant OCS controller. Verify that the controller recognizes the DSTD108 unit with no communication errors. Test each channel by activating the corresponding digital output and verifying that the relay switches correctly — listen for the relay click and measure the output voltage to confirm proper switching. Run a test sequence that exercises all 8 channels to verify stable performance.

Technical FAQ

What is the DSTD108 used for? The DSTD108 is an 8-channel relay output connection unit for the ABB Advant OCS / S100 I/O system. It provides relay-based switching between the controller’s 24 VDC digital output signals and field devices operating at 24–250 VAC/VDC, such as contactors, solenoid valves, indicator lights, and motor starters. The integrated relays provide galvanic isolation to protect the controller from voltage spikes on the load side.

What are common failure modes for this unit? Common failure modes include: relay contact wear from repeated switching or excessive load current; relay coil failure from electrical overstress or aging; connector pin damage from repeated insertion/removal or loose wiring; and contact welding from switching high inrush currents without proper protection. In most cases, a failing DSTD108 will cause one or more output channels to fail to switch, which can be diagnosed by testing each channel individually.

Is the DSTD108 still in production? The DSTD108 is a discontinued product, with supply now limited to spare parts inventory (New Original / New Surplus). For plants maintaining mature Advant OCS installations, having verified genuine DSTD108 units on hand is critical for lifecycle support, as availability from ABB’s direct supply chain may be limited.

What warranty do you offer on New Surplus parts? We provide a full 12-month warranty on all New Original / New Surplus units. This is fundamentally different from refurbished or pulled units, which often carry 30–90 day warranties and come with unknown operational history, potential relay contact wear, and degraded component performance. For a relay connection unit that is critical to field device switching, the reliability difference between new surplus and refurbished directly impacts production uptime and the risk of unexpected output failures.