AAM21 | Yokogawa | Input Module

Description

The Yokogawa AAM21 functions as an Input Module designed for thermocouple signal acquisition, supporting multiple IEC and JIS standard sensor types with software‑defined input ranges.

Hardware Specifications

• Model: AAM21

• Brand: Yokogawa

• Origin: Japan

• Weight: Not specified

• Dimensions: Not specified

• Operating Temp: Not specified

• Power Consumption: ≤150 mA at 5.0 V DC

• Input Signal: JIS/IEC thermocouple types K, T, J, E, B, R, S, N

• Input Range: -50 to 150 mV

• Allowable Input Voltage: -0.5 to 4.0 V DC (between terminals B-C)

• Input Resistance: 1 MΩ at power‑up (3 kΩ at power‑down)

• Accuracy: ±20 µV

• Data Update Period: 100 ms

• Signal Source Resistance: ≤1000 Ω

• RJC Input: -10 to 70 deg C

• RJC Accuracy: ±1 deg C

• Auxiliary Voltage Output: 1 to 5 V DC; ≤1 Ω output resistance; ≥10 kΩ load resistance; range 0.5 to 5.5 V DC

• Burnout Detection: Selectable UP/DOWN/OFF; detection time ≤60 s; detection current 0.1 µA (terminal B only)

• Signal Isolation: Input signals insulated between systems; withstand voltage 1500 V AC/min

• Effect of Signal Source Resistance: 1 kΩ → conversion error ≤±20 µV

• Effect of Ambient Change: 10 deg C → mV input ±40 µV; thermocouple input ±40 µV; RTS input ±0.16 Ω; potentiometer input ±0.4 % span; auxiliary output ±24 mV

• Installation: AMN11 Nest for Analog I/O Modules

• Wiring: M4 screw terminal connection

• Input Signal Specification: Defined via software setting

Cold Junction Compensation (CJC)

The AAM21 incorporates cold junction compensation (CJC) to stabilize thermocouple measurements across varying ambient conditions. RJC input accuracy is maintained within ±1 deg C, ensuring consistent conversion of low‑level millivolt signals. Burnout detection provides selectable UP/DOWN/OFF states, enabling system‑level fault handling within 60 s.

Frequently Asked Questions (FAQ)

Q: How is burnout detection configured? A: Burnout detection can be set to UP, DOWN, or OFF via software, with detection current limited to 0.1 µA at terminal B.

Q: What is the impact of ambient temperature variation on measurement accuracy? A: A 10 deg C change results in ±40 µV drift for mV and thermocouple inputs, ±0.16 Ω for RTS inputs, and ±0.4 % span for potentiometer inputs.

Q: Can auxiliary voltage output be used for external reference devices? A: Yes, provided load resistance is ≥10 kΩ and grounding is shared with the system.

Field Installation Guidelines

• Install the module into the AMN11 Nest for Analog I/O Modules.

• Connect wiring to terminal blocks using M4 screws with proper torque.

• Maintain shield grounding at a single point to prevent ground loops.

• Separate signal wiring from high‑voltage cabling to minimize interference.

• Configure input signal type and range via software before commissioning.