Description
The Omron Delta Tau ACC-70E is a specialized TAMAGAWA encoder interface accessory board engineered for the Universal Multi-Axis Controller (UMAC) and Turbo PMAC2 motion control platforms. Operating on the standard 3U UBUS backplane system, this module decodes high-resolution serial position data from Tamagawa FA-CODER encoders, making it a critical infrastructure component in nanometer-positioning and semiconductor manufacturing equipment.
Commercial Availability & Terms
- Condition: Available as New Surplus (Factory Sealed) or Refurbished Legacy Stock (backplane-verified and dynamic loop-tested).
- Availability: In stock; standard fulfillment dispatch occurs within 24 to 48 hours.
- Warranty: 12-month comprehensive depot warranty.
- Pricing Note: Value is determined by current market availability and industrial surplus demands. Contact our motion control logistics team for a firm, formal quotation.
Technical Specifications
| Parameter | Value / Specification |
| Manufacturer | Omron Delta Tau Data Systems |
| Part Number | ACC-70E (Assembly Base: 603692-102) |
| Interface Format | 3U Eurocard form factor for UMAC UBUS architectures |
| Protocol Type | Tamagawa RS-485 Multi-drop Serial Protocol (2.5 Mbps) |
| Channel Capacity | 2 channels standard; expandable to 4 channels via Option 1 |
| Supported Data Formats | Data ID3: 17-bit single-turn, 16-bit multi-turn, 8-bit alarm |
| Hardware Scalability | Up to 16 cards (64 channels maximum) per single UMAC rack |
| Addressing Hardware | Multi-position DIP Switch (S1) for base PMAC memory address selection |
| Battery Low Monitor | Integrated voltage detection trigger at \le 2.3 V DC (Red LED D1 indicator) |
Protocol Execution & Timing Constraints
The ACC-70E functions symmetrically with the PMAC host’s internal servo or phase clocks. The rising edge of the system clock coordinates the timing cycle:
- Clock Trigger: The interface reads the rising edge and immediately initiates the serial data request frame.
- Telemetry Phase (2.2\ \mus): Within 2.2\ \mus of the trigger, the ACC-70E extracts the diagnostic error bits from the preceding frame and commands the encoder to buffer the next position state.
- Data Transmission Loop (50 to 100\ \mus): The encoder returns the updated 17-bit single-turn and 16-bit multi-turn registers back across the differential RS-485 physical layer.
Encoder Compatibility Constraints
The module is hardwired for serial communication with Tamagawa absolute encoder series, explicitly supporting the FA-CODER TS5667N420-SA48 and FA-CODER TS5667N120-SA35 models. Connecting non-serial incremental encoders or alternative proprietary protocol structures will output corrupt register frames or generate immediate tracking axis faults in the Turbo PMAC executable loop.
Field Engineering & Maintenance Practices
Hardware Addressing (S1 DIP Switch)
Before sliding the card into the 3U UBUS chassis rack, technicians must configure the S1 DIP switch block. This establishes the base register offset address accessed by the Turbo PMAC CPU via the UBUS. If you are replacing an existing faulty board, replicate the exact on/off toggles from the removed hardware to align the physical memory addresses with the existing Encoder Conversion Table (ECT) definitions in your motion code.
Battery Absolute Retention Line
The ACC-70E layout incorporates an onboard battery backup circuit designed to keep the encoder’s multi-turn position counters alive when the main 24 V logic bus is switched off.
- Low Battery Voltage: If the onboard voltage monitor drops to 2.3 V DC, the red LED D1 illuminates.
- Maintenance Mandate: Do not power down the system while LED D1 is active. Replace the battery while the control system remains energized to avoid losing the absolute homing reference points, preventing the need for axis realignment.
Frequently Asked Questions
How do I configure the card to combine single-turn and multi-turn encoder values?
Data recombination is managed within the PMAC software environment using specific memory offsets defined in the ACC-70E manual. You must map the respective upper and lower memory words into the Encoder Conversion Table (ECT) processing definitions, applying a bitwise shifting structure that mirrors the Tamagawa ID3 data structure.
Can I install the ACC-70E into a standard PC PCI slot?
No. The ACC-70E is a 3U Eurocard built specifically for the modular UMAC (Universal Motion and Automation Controller) chassis architecture using the UBUS backplane interface. For standalone PCI or PCIe controller variants, Delta Tau provides equivalent option boards (such as the ACC-24P series) matching that specific physical bus.
What are the symptoms of serial line degradation on the ACC-70E?
Line degradation typically triggers intermittent phase clock overruns or missing data block errors. This usually stems from running long unshielded twisted-pair wires alongside motor phase cables or neglecting the characteristic termination line requirements needed for 2.5 Mbps differential transmission. Ensure line shielding is terminated directly to the chassis ground plate near the UMAC rack.
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