Product Core Brief
- Model: SC200S
- Brand: Yokogawa
- Series: EXA SC200 2-Wire Conductivity / Resistivity Analyzer
- Core Function: Intrinsically safe 2-wire transmitter for conductivity and resistivity measurement in hazardous-area process applications.
- Product Type: 2-Wire Conductivity / Resistivity Transmitter
- Key Specs: Intrinsically safe model | 2-wire loop-powered | conductivity or resistivity measurement | LCD display | µS/cm, mS/cm units
- Condition: New Original / New Surplus
Key Technical Specifications
- Manufacturer: Yokogawa
- Part Number:
- Product Family: EXA SC200 series
- Model Variant: SC200S — intrinsically safe version of the SC200 2-wire conductivity analyzer
- Measurement Type: Conductivity and resistivity
- Display: Custom LCD, 3½-digit main display with alphanumeric message line
- Units: µS/cm, mS/cm
- Power / Wiring: 2-wire loop-powered transmitter
- Safety Classification: Intrinsically safe model; exact approval markings must be verified on the nameplate
- Compatible Sensors: Yokogawa EXA SC series conductivity sensors; cell constant and sensor type must be confirmed during configuration
- Mounting: Field-mounted transmitter, typically installed near sensor or in a local instrument enclosure
- Typical Applications: Process water monitoring, chemical dosing control, pure water systems, hazardous-area conductivity loops, OEM skids requiring IS instrumentation
Product Introduction
The Yokogawa SC200S is the intrinsically safe variant of the EXA SC200 2-wire conductivity and resistivity transmitter. It is designed for process applications where conductivity or resistivity must be measured reliably in hazardous or classified areas while maintaining simple 2-wire loop integration.
As part of the EXA SC200 family, it provides real-time microcontroller-based measurement, local LCD indication, and straightforward configuration for conductivity or resistivity service. For plant maintenance and instrumentation teams, the SC200S is a practical replacement or spare for existing Yokogawa 2-wire conductivity loops, especially where intrinsic safety certification is required.
QA & Testing SOP
Because this is an intrinsically safe field transmitter, inspection focuses on nameplate verification, loop integrity, and sensor compatibility.
- Nameplate verification: Confirm model SC200S, serial number, intrinsic safety markings, and manufacturing data.
- Visual inspection: Check housing, cable entries, display window, terminal block, and sensor connector for damage, corrosion, or moisture ingress.
- Loop power-up test: Energize with a suitable 2-wire loop supply and verify normal display, startup behavior, and stable current output.
- Sensor simulation check: Connect a compatible Yokogawa conductivity sensor or use a known cell constant setting to verify measurement response.
- Output verification: Confirm 4–20 mA loop output tracks measurement changes according to configured range.
- ESD-safe packing: Ship with terminal and display protection, plus nameplate photos for receiving QA.
Installation Pitfalls & Guide
❗ Do not substitute SC200S with a non-IS model in hazardous areas. The “S” variant is the intrinsically safe version; using a general-purpose model in a classified area may violate area certification.
❗ Confirm loop voltage and current limits. As a 2-wire transmitter, the SC200S depends on adequate loop supply voltage. Insufficient loop voltage can cause unstable display or output errors.
❗ Verify sensor compatibility and cell constant. The transmitter must match the connected conductivity sensor type and cell constant; incorrect settings will produce ina
ccurate readings.
❗ Check intrinsic safety documentation. IS installations usually require matching barriers, isolators, cables, and area classification records. Do not rely on physical fit alone.
Replacement steps:
- Pre-install: Confirm loop power, IS documentation, sensor type, and cell constant.
- Isolate loop: De-energize the 2-wire loop and verify safe work conditions.
- Replace unit: Disconnect wiring, remove the transmitter, install the SC200S, and reconnect terminals.
- Commission: Restore loop power, verify display, check sensor connection, confirm 4–20 mA output, and record final configuration.
Technical FAQ
Is pricing flexible? Yes. Price depends on condition, stock availability, nameplate completeness, intrinsic safety markings, and whether the unit is new original or new surplus.
What warranty is included? Surplus field transmitters usually carry a limited functional warranty, often 30–90 days, unless otherwise agreed. Final terms depend on stock source and customer QA requirements.
How is SC200S different from SC200? The SC200S is the intrinsically safe version of the EXA SC200 2-wire conductivity transmitter, while the standard SC200 is the general-purpose model.
Can it measure resistivity? Yes. The EXA SC200 family supports conductivity and resistivity measurement; configuration must match the application and sensor.
Do you provide test records? We can provide nameplate photos, loop power-up notes, display checks, and output verification records. Full calibration reports can be arranged if required.
