AAI835-H00 Yokogawa CENTUM Analog I/O Module
Manufacturer: Yokogawa
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Part Number: AAI835-H00
Condition：New with Original Package
Product Type: Analog Input/Output Modules
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Country of Origin: Japan
Payment:T/T, Western Union
Shipping port: Xiamen
Warranty: 12 months
Yokogawa AAI835-H00 S1 Isolated Analog Input/Output Module
The Yokogawa AAI835-H00 S1, also cataloged as the AAI835-H00 Isolated Analog Input/Output Module, operates as a dedicated hardware component for bi-directional 4-20 mA current signal conditioning and HART protocol pass-through within Yokogawa CENTUM VP and CENTUM CS 3000 DCS platforms.
Suffix Breakdown & Model Matrix
| Code | Type | Description |
|---|---|---|
| AAI835 | Base Model | Isolated Analog Input/Output Module (4-20 mA) |
| -H | HART Support | Integrated digital communication for HART smart devices |
| 0 | Standard Type | Always set to 0 |
| 0 | Option Type | Basic type without explosion protection |
| S1 / S2 | Style Code | Hardware style release revision |
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | AAI835-H00 S1 |
| Brand | Yokogawa |
| Origin | USA |
| Weight | 0.32 kg |
| Dimensions | 3.2 cm x 10.7 cm x 13 cm |
| Operating Temp | 0 to 55 deg C |
| Power Consumption | Max. 360 mA at 5 VDC; 450 mA at 24 VDC |
| Channel Configuration | 4 Analog Inputs + 4 Analog Outputs |
| Signal Range | 4-20 mA DC (Inputs and Outputs) |
| Input Accuracy | +/-16 uA |
| Output Accuracy | +/-48 uA |
| Data Update Period | 10 ms |
| Allowable Output Load | 0 to 750 ohm |
| Power-ON Input Resistance | 290 ohm at 20 mA to 450 ohm at 4 mA |
| Power-OFF Input Resistance | 500 kohm or higher |
| Isolation Voltage | 500 VAC for 1 minute |
HART Protocol & Channel Isolation Performance
The module superimposes 4-20 mA HART loop protocol digital communication across all input and output channels without disturbing analog process variables. Individual channel isolation prevents ground loop interference and protects backplane logic from field voltage spikes. Integrated transmitter loop power delivers a minimum of 15.0 VDC at 20 mA, while output loops actively support load resistances up to 750 ohm.
Frequently Asked Questions
Q: What happens to the module input impedance during a complete 24 VDC power loss?
A: During normal operation, the input resistance varies between 290 ohm and 450 ohm depending on loop current. Upon total loss of system power, internal switching shifts the input circuit impedance to 500 kohm or higher, preventing excessive loading on field loops.
Q: How does the hardware handle open-circuit conditions on analog output loops?
A: The onboard diagnostic circuitry continuously scans output channels for open loops. When loop current drops below 0.65 mA, the module triggers a circuit-open detection alarm and transmits diagnostic status bytes to the DCS controller over the internal system bus.
Q: Which terminal interface hardware connects field wiring to the module?
A: Field connections route through pressure-clamp terminal blocks, dedicated KS1 interface cables, or 40-pin MIL connector cable assemblies tied to ATI3S or ATI3D terminal boards via ATK4A or ATB3A adapters.
Field Installation Guidelines
Mount the module into a designated rack slot on the Yokogawa FIO base unit. Ensure the top and bottom retention mechanism latches completely into the backplane to prevent contact resistance build-up.
When routing analog signal wiring, route twisted shielded pair cables through isolated cable trays separated by at least 100 mm from high-voltage AC lines. Connect the cable shield drain wire directly to the cabinet signal ground bar at a single point to prevent ground loops. Verify that total loop resistance on output channels remains within the 0 to 750 ohm operating window before energizing field transmitters.