Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | A1S68DAI |
| Manufacturer | Mitsubishi Electric |
| Product Type | Analog Output Module (D/A Converter) |
| Product Series | MELSEC-A (AnS/QnAS) |
| Output Channels | 8 channels |
| Output Signal Range | DC 4–20 mA |
| External Load Resistance | 0–600 Ω |
| Digital Input Value | 0–4095 (1/4000 resolution) |
| Maximum Resolution | 4 µA |
| Overall Accuracy | ±1.0% (±200 µA) |
| Conversion Speed | 4 ms / 8 channels |
| Isolation | Photocoupler between output terminals and PLC power; non-isolated between channels |
| Connection Terminal | 20-point screw-clamp terminal block |
| Internal Current Consumption | 0.85 A at 5 VDC |
| Weight | Approximately 0.22–0.28 kg |
Main Features and Advantages
8-Channel Current Output with High Density: The A1S68DAI consolidates eight independent 4–20 mA analog output channels into a single local unit module, maximizing analog output density within the MELSEC-A rack. This high channel count reduces the number of module slots required for analog control applications, optimizing rack space utilization in control cabinets where available slots are limited. Each channel operates independently, allowing the PLC CPU to control eight separate analog loops through a single A1S68DAI module.
Fast Conversion and Responsive Control: The A1S68DAI achieves a maximum conversion time of 4 milliseconds across all eight channels, ensuring that analog output values update quickly enough to support responsive closed-loop control . This conversion speed is suitable for a wide range of process control applications where timely actuator response is essential for maintaining loop stability and product quality. The module’s digital input range of 0–4095 provides a 1/4000 resolution with a maximum analog resolution of 4 µA .
Photocoupler Isolation for Field Protection: The A1S68DAI incorporates photocoupler isolation between the output terminals and the PLC power supply, shielding the controller from electrical transients, ground loops, and voltage spikes that can occur on field wiring . This isolation is particularly important in industrial environments where variable frequency drives, solenoid valves, and other inductive loads can introduce significant electrical noise into analog signal circuits. The output short protection feature further safeguards the module against wiring faults that could otherwise damage the output circuitry .
Analog Output HOLD/CLEAR Functionality: The A1S68DAI supports configurable HOLD/CLEAR behavior for analog outputs when the PLC CPU transitions to STOP status or encounters an error . This function allows system designers to define whether analog outputs hold their last value or transition to a safe state during controller shutdown, enabling fail-safe behavior appropriate to the specific process application. The HOLD/CLEAR setting is applied to all channels simultaneously via a front-panel terminal on the module.
