Configured for liquid‑phase pH measurement in process loops, the Honeywell 51451326-503 (Meredian II pH probe) provides direct electrochemical sensing through a combination glass electrode assembly. The probe uses integral tinned‑lead cabling for signal continuity and supports immersion or in‑line mounting across UCN‑connected measurement paths.
Hardware Specifications
Parameter
Specification
Model
51451326-503
Brand
Honeywell
Origin
Not specified
Weight
Not specified
Dimensions
Not specified
Operating Temp
32 deg F to 212 deg F (0 deg C to 100 deg C)
Power Consumption
Passive electrochemical sensor; no active draw
Core Performance Indicators
Meredian II combination pH electrode with 20 ft (6.10 m) integral cable
4-20 mA HART Loop Protocol Behavior
Although the probe itself outputs a raw millivolt signal, it is typically paired with Honeywell transmitters that convert the electrode potential into a 4-20 mA HART loop. Stable electrode impedance ensures predictable loop scaling, minimizing drift during temperature compensation cycles. Channel‑to‑channel isolation in associated transmitters prevents cross‑talk when multiple probes share the same enclosure or manifold.
Frequently Asked Questions
Q: Can the 51451326-503 be installed in a pressurized in‑line holder? A: Yes, provided the holder is rated for the process pressure and maintains proper sealing around the probe body.
Q: Does the probe require polarization time after installation? A: Combination pH electrodes typically stabilize within minutes, but final calibration should be performed after thermal equilibrium is reached.
Q: Can the integral cable be extended? A: Extension is possible only with high‑impedance pH‑rated cable. Standard signal cable may introduce noise or offset errors.
Field Installation Guidelines
Install the probe in a location with continuous wetting of the sensing tip.
Avoid routing the cable parallel to high‑voltage conductors to reduce induced noise.
Maintain immersion depth sufficient to cover the reference junction.
Use proper grounding practices on associated transmitters to prevent measurement offset.
Rinse the electrode with clean water before insertion to avoid contamination.
