Configured for multi-parameter liquid analysis in industrial process networks, the YOKOGAWA FLXA21 (FLXA21 Liquid Analyzer) provides direct physical and electrical execution of pH, ORP, dissolved oxygen, and conductivity measurements via modular sensor inputs.

Suffix Breakdown & Model Matrix

The FLXA21 utilizes a modular suffix code system to determine specific input configurations and output communication protocols.

• Sensor Input: Configurable for single or dual-channel operation, allowing simultaneous measurement of independent parameters.
• Communication: Options include support for 4-20 mA analog outputs, FOUNDATION Fieldbus, or Profibus PA digital communication standards.
• Enclosure: Available in wall-mount or pipe-mount configurations with IP66/NEMA 4X ingress protection ratings.

Hardware Specifications

Process Control Connectivity and Loop Performance

The FLXA21 controller incorporates advanced signal processing to manage high-impedance sensor inputs. The architecture supports channel-to-channel isolation, preventing common-mode interference when multiple sensors are deployed in the same process stream. For pH and ORP monitoring, the internal circuitry executes real-time cold junction compensation (CJC) and automatic temperature compensation (ATC) to ensure measurement stability. When integrated into a DCS environment, the device utilizes FOUNDATION Fieldbus or Profibus PA connectivity to transmit process variables and diagnostic data, maintaining loop integrity through standardized digital communication protocols.

Frequently Asked Questions

Q: Does the FLXA21 support field replacement of input modules?

A: Yes, the modular design allows for the installation or replacement of sensor-specific input modules. Ensure the device is isolated from power before module removal or re-configuration.

Q: How is signal drift managed during long-term conductivity measurement?

A: The controller utilizes internal digital signal processing to perform continuous diagnostic monitoring and self-calibration routines. Periodic calibration using certified reference solutions is required to maintain accuracy within specified tolerances.

Field Installation Guidelines

1. Select a mounting location with minimal mechanical vibration and protection from direct sunlight or heavy process sprays.
2. Ensure the enclosure seal is intact before mounting to maintain the IP66 rating.
3. Use dedicated conduits for sensor signal cables to prevent crosstalk with high-voltage power lines.
4. Ground the transmitter chassis to a low-impedance earth point to provide effective surge protection and signal shielding.
5. Terminate shield wires at the designated terminals provided within the housing; avoid creating ground loops between the transmitter and the process piping.
6. Verify electrical connections against the specific wiring diagram provided with the internal module configuration prior to applying power.