Endress+Hauser CLM253 Modules: CLM253-CD0005

Technical Dossier

Product Details And Specifications

Endress+Hauser CLM253 Series: Comprehensive Module Range and Technical Overview

The Endress+Hauser CLM253 is a two-wire conductivity transmitter engineered for continuous inline measurement in demanding process environments. Deployed across global heavy industry — including chemical plants, nuclear facilities, cooling water circuits, pharmaceutical production, and oil refinery utility systems — the CLM253 series occupies a critical position in process analytical instrumentation. Its compact DIN rail or panel-mount form factor, combined with HART communication capability and dual-limit relay outputs, made it a standard-specification instrument for distributed control system (DCS) integration throughout the 2000s and 2010s. Installed base counts in the tens of thousands across EMEA, Asia-Pacific, and North American process plants confirm its role as a backbone conductivity measurement device for conductivity ranges from 0.01 µS/cm to 500 mS/cm.

The Evolution of CLM253 Architecture

The CLM253 belongs to Endress+Hauser's Mycom S transmitter platform, which succeeded the earlier CLM151 and CLM223 single-channel analog transmitters. The CLM253 introduced dual-channel capability and digital HART 5/7 communication, enabling remote parameterization and integration with asset management systems such as Endress+Hauser's FieldCare and third-party HART masters. Early hardware revisions (A/B suffix) used a discrete analog front-end; later C/D revisions migrated to a microcontroller-based signal chain with improved temperature compensation algorithms. The CLM253 is compatible with inductive (toroidal) conductivity sensors from the CLS50, CLS52, and CLS54 families, as well as conductive sensors from the CLS15 and CLS21 families, provided the correct order code suffix is selected. As of 2020, Endress+Hauser formally transitioned new project specifications to the CM444 and CM448 Memosens-based platform. The CLM253 is now in the mature/end-of-active-production phase; however, installed base support, spare parts, and calibrated replacement units remain commercially available through authorized distributors and specialist spare parts suppliers.

CLM253 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly sourced variants within the CLM253 product family. Each order code encodes sensor input type, output configuration, approval class, and housing variant.

CLM253-CD0005: Two-wire HART transmitter, inductive sensor input, 4–20 mA output, standard housing, no Ex approval — the baseline catalog reference for non-hazardous area installations.
CLM253-CD0015: Two-wire HART, inductive input, 4–20 mA, ATEX Zone 1 Ex ia IIC T4 approval for gas-group hazardous areas.
CLM253-CD0025: Two-wire HART, inductive input, 4–20 mA, FM/CSA Class I Div 1 approval for North American hazardous locations.
CLM253-CD0035: Two-wire HART, inductive input, dual relay output variant, standard housing, non-Ex — used where local limit switching is required without a separate relay module.
CLM253-CE0005: Two-wire HART, conductive sensor input (0–2000 µS/cm range), 4–20 mA output, standard housing — specified for low-conductivity ultrapure water and boiler feedwater applications.
CLM253-CE0015: Conductive sensor input, ATEX Zone 1 Ex ia approval, 4–20 mA HART output — for hazardous area pure water monitoring.
CLM253-CE0025: Conductive sensor input, FM/CSA Class I Div 1, 4–20 mA HART — North American Ex-rated pure water variant.
CLM253-CF0005: Two-wire HART, inductive input, extended temperature range (-20 to +60 °C ambient), standard housing — specified for outdoor or unheated enclosure installations.
CLM253-CF0015: Extended temperature, inductive input, ATEX Zone 1 Ex ia, 4–20 mA HART.
CLM253-CG0005: Two-wire HART, inductive input, field housing (IP67 polycarbonate enclosure) — for direct pipe or wall mounting without a separate junction box.
CLM253-CG0015: Field housing, inductive input, ATEX Zone 1 Ex ia, 4–20 mA HART.
CLM253-CH0005: Two-wire HART, conductive input, field housing IP67, standard temperature, non-Ex — for outdoor conductive conductivity measurement.
CLM253-CH0015: Conductive input, field housing, ATEX Zone 1 Ex ia.
CLM253-CJ0005: Panel-mount version, inductive input, 4–20 mA HART, 96×96 mm DIN cutout — for control room or local panel integration.
CLM253-CJ0015: Panel-mount, inductive input, ATEX Zone 1 Ex ia, 4–20 mA HART — for Ex-rated panel installations in Zone 1 classified control rooms.

Sourcing Hard-to-Find & Obsolete CLM253 Parts

With the CLM253 series in its mature/end-of-production lifecycle, procurement teams at chemical plants, water treatment facilities, and power generation sites face increasing lead times through standard distribution channels. DriveKNMS maintains a dedicated inventory of CLM253 units — including low-volume order codes such as Ex-rated field housing variants and dual-relay configurations — sourced from decommissioned plant equipment, authorized surplus, and factory-refurbished stock. All units are supplied with full order code verification against the Endress+Hauser product configurator database. For sites requiring long-term maintenance agreements or multi-unit blanket orders to cover 5–10 year maintenance cycles, DriveKNMS provides lifecycle extension support including cross-reference mapping to CM444/CM448 Memosens replacements where direct substitution is not feasible. Customers are advised to submit their full instrument tag list (including order code, serial number, and hardware revision) to enable accurate compatibility assessment before procurement.

Quality Control for the CLM253 Range

The CLM253 transmitter incorporates a dual-channel analog front-end with HART modem and non-volatile parameter storage. DriveKNMS applies a structured test protocol to all CLM253 units prior to dispatch. Each unit undergoes power-on verification at rated supply voltage (16–36 V DC two-wire), HART communication handshake test using a calibrated HART communicator (Emerson 475 or equivalent), and 4–20 mA output linearity check across five calibration points using a precision current loop calibrator. Inductive sensor input simulation is performed using a decade resistance box to verify the conductivity cell constant compensation circuit. For units with relay outputs, contact closure and setpoint response are verified against factory-default parameters. Units with ATEX or FM/CSA markings are inspected for enclosure integrity, terminal block condition, and label legibility before shipment. A test report is issued with each unit upon request.

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