Endress+Hauser CM448 Liquiline 8-Channel Transmitter

CM448 Liquiline eight-channel field transmitter

The Endress+Hauser CM448 is the largest member of the Liquiline CM44x field transmitter group. It is a four-wire, mains or 24 V DC powered controller in a robust plastic housing, and it can take up to eight digital Memosens sensors on a single device. Where a CM442 handles two sensors and a CM444 handles four, the CM448 is chosen when one cabinet-free, wall or pipe-mounted unit must serve many measuring points. Seven Star LLC, an independent supplier in Muscat, supplies the CM448 and the matching Memosens sensors, cables and assemblies in Oman and the GCC.

Because the CM448 is built from modules, the part number alone does not fix the configuration. The device you receive is defined by the order code from the Product Configurator: how many sensor channels, whether current outputs and relays are fitted, which fieldbus is used, and which power supply. That is why the checklist further down is worth following before an inquiry is sent.

CM448 technical specifications

How the CM448 handles eight measuring channels

The base module (BASE2-E) carries two Memosens inputs, two optional current outputs and the main communication interface. Each additional 2DS module adds two further Memosens inputs, and the device is extended slot by slot up to eight channels. Remaining slots can hold current output modules (2AO), current input modules (2AI), relay modules (2R or 4R), a combined AOR module with two current outputs and two relays, or a DIO module with two digital inputs and two digital outputs. A maximum of two DIO modules may be used, and upgrades to the 4AO module are limited to one.

Inside the transmitter, each channel can run its own calibration, cleaning and limit functions, and mathematical functions combine channels into calculated values, for example a difference between two conductivity sensors. A controller function, cleaning relay logic and an alarm relay are available. Settings and logbooks are held in non-volatile memory, and a real-time clock keeps time stamps correct after a power cut. An SD card slot supports software updates and copying a set-up from one device to another.

CM448 communication options and integration

For a distributed control system the CM448 can be ordered or upgraded with PROFIBUS DP (module 485DP) or Modbus RS485 (module 485MB), or with an Ethernet-based option activated by code: Modbus TCP, EtherNet/IP or PROFINET, each together with the web server. HART is also released by activation code. Note the rule that fitting a 485DP or 485MB module disables the existing current outputs of the base module, and that only two current outputs can be used together with the 485DP module, while up to six can be used with an Ethernet fieldbus.

The PROFIBUS and Modbus interfaces provide 16 measured values and several digital values, and accept setpoints back from the control system. FieldCare and the W@M asset platform can be used for device management. This makes the CM448 suitable as a single gateway for a whole analysis skid rather than eight separate transmitters.

Related Liquiline parts: CM442, CM444, CM42B and CM442R

The same TI document covers the CM442 and CM444 field transmitters, which share housing, display and modules with the CM448. The CM442R is the DIN-rail variant with an optional external display, and the CM42B is a different two-wire single-channel design. A Seven Star LLC quotation for a CM448 will normally list the sensor models, for example pH Memosens CPS sensors, conductivity CLS sensors or the CCS51E free chlorine sensor, because the transmitter only works as a complete measuring point with sensors, Memosens cables (CYK10, CYK11) and, where needed, assemblies such as the CPA842 or CPA875.

Selection checklist for a CM448

• Channels: count current and future Memosens sensors; the CM448 holds up to eight.
• Parameters: list pH, ORP, conductivity, oxygen, turbidity, nitrate and other sensors, and confirm each sensor is Memosens.
• Power: choose 100 to 230 V AC or 24 V DC, and confirm the supply has no built-in switch, so a labelled circuit breaker is needed nearby.
• Outputs: specify the number of 4 to 20 mA outputs and relays for dosing, cleaning and alarms.
• Fieldbus: choose HART, PROFIBUS DP, Modbus or an Ethernet protocol, and note the effect on the current outputs.
• Hazardous area: the document describes an intrinsically safe sensor module (2DS Ex-i) for some versions; confirm the exact order code and its Ex documentation if sensors sit in a classified zone.
• Cable glands: M16, M20 or NPT thread to suit site conduit.

Installing and commissioning the CM448

The enclosure is made for wall, post or pipe mounting, and its IP66/67 rating suits outdoor skids when the ambient stays within -20 to 55 °C. Use a sun shield in Gulf summers, because radiant heat on a plastic housing can push internal temperature above the ambient reading. Route Memosens cables up to 100 m, separate from power cables, and tighten factory-fitted glands to the specified torque. Fit a labelled circuit breaker near the device.

During commissioning, assign each sensor to a channel in ascending slot order, set the engineering units, enter calibration data stored in the Memosens sensor heads, define alarm limits and relay behaviour, and test the output ranges. Keep a copy of the configuration on the SD card as a backup.

Maintenance and spare modules for the CM448

Because the modules are identical across the Liquiline platform, a small stock of 2DS, 2AO, 2R and AOR modules gives fast recovery. The display, glands and seals are replaceable. Replace seals if the housing is opened often in dusty or salt-laden air. Memosens sensors carry their own calibration, so a failed sensor is swapped without re-wiring. Log the firmware version before and after any update.

CM448 applications in Oman and the GCC

Multi-channel analysis is common in desalination pre-treatment and post-treatment, where pH, conductivity and free chlorine are monitored in parallel, in boiler feed and cooling water at power and petrochemical sites, in wastewater treatment, and in food and beverage plants. The CM448 lets one unit serve a whole skid, which saves cable and cabinet space, and its IP66/67 housing tolerates washdown and humid coastal air.

Information to send with a CM448 request

• Number and type of Memosens sensors and their model numbers
• Supply voltage and mounting method (wall, post or pipe)
• Required current outputs, relays and digital inputs
• Fieldbus protocol and DCS or PLC brand
• Hazardous area classification, if any
• Cable gland thread and cable lengths
• Quantity and delivery location in Oman or the GCC

Documents and quotation

The manufacturer technical information for the CM448 is attached on this page. It describes the modules, the order structure and the technical data quoted above.

Send the order code or the list of sensors and signals you need for the CM448 and Seven Star LLC will confirm availability and quote.