Yokogawa AMM11 Magnetic Flow Converter

The Yokogawa AMM11, also cataloged as the AMM11 Magnetic Flow Converter, operates as a dedicated hardware component for converting signals from magnetic flow tubes into standardized outputs within ADMAG series process networks.

Hardware Specifications

Process Control & DCS Instrumentation Properties

The Yokogawa AMM11 utilizes dual-frequency excitation techniques on flow tube sizes up to 400 mm to maintain tight zero-point stability when tracking slurry fluids or high-noise process variables. The microprocessor-driven instrument passes active flow dynamics down a 4-20 mA HART loop protocol track or BRAIN communication network, adjusting output scaling on the fly via multi-range and bi-directional calculation subroutines. To prevent ground loop noise from corrupting the low-level electrode voltages, the hardware decouples the 4-20 mA current loops from the internal processing rails using channel-to-channel isolation circuits.

Frequently Asked Questions

Q: How does the dual-frequency excitation architecture protect the 4-20 mA current output from slurry fluid noise?

A: The converter combines high-frequency and low-frequency excitation current profiles simultaneously. The high-frequency wave suppresses electrochemical noise caused by slurry solids colliding with the flow tube electrodes, while the low-frequency wave keeps the zero-point steady, ensuring an uncorrupted 4-20 mA process signal.

Q: What are the transmission cable constraints when tracking remote installations over long distances?

A: The physical distance between the magnetic flow tube and the AMM11 converter must not exceed a maximum length of approximately 2 km (6500 ft). Wiring runs require standard PVC-sheathed control cables with clean shielding to prevent electromagnetic ambient noise from breaking down signal integrity.

Q: How does the internal EEPROM layout handle power failures without an attached backup battery module?

A: The converter stores all calibration values, meter constants, and user configuration matrices directly inside a non-volatile EEPROM chip. If utility power drops completely, the data remains intact indefinitely, allowing the module to resume accurate flow measurements instantly upon power restoration.

Field Installation Guidelines

• Mechanical Mounting Stability: Secure the converter onto a standard 2-inch pipe stand, flat panel surface, or rigid wall assembly. Check that all integrated hardware bolts are tight to prevent local industrial pipeline vibrations from causing case fatigue or terminal loosening.
• Grounding Field Circuits: Establish a low-impedance ground connection to the main frame terminal with a resistance value less than or equal to 100 Ohm. If the integrated surge arrestor function is utilized, the grounding network path resistance must be kept under 10 Ohm.
• Transistor Output Protection: Install an external suppression diode or flyback barrier across the terminals of any connected low-power external relays. This setup shields the pulse and alarm transistor contacts from high-voltage spikes caused by inductive switching fields.
• Cable Gland Seals: Tighten all cable gland assemblies around the incoming signal and power conductors to preserve the NEMA 4 environmental rating. Seal any unused conduit ports with verified threaded plugs to prevent moisture or dust from entering the electronics bay.