Danfoss CMA Sectional Mobile Valves

Danfoss CMA valves are advanced, CAN-enabled electrohydraulic sectional mobile valves, available in two systems: CMA90 and CMA200. Both use integrated pressure and position sensors for independent metering control, giving precise, repeatable control of both pressure and flow on each side of a cylinder or motor, with sub-micron hysteresis through closed-loop control over spool position. Where conventional mobile valves often compromise on precision or response, CMA delivers both.

CMA90 offers two work section types that can be combined in the same valve bank: CMA sections, providing independent metering control on both work ports of a single double-acting service (or two single-acting services); and CMT sections, providing precise pre-compensated flow control across two independent double-acting services from a single section. CMA200 is a higher-flow system offering CMA-type independent metering only, without a CMT equivalent.

Each work section has its own on-board electronics, embedded sensors and independent pilot spools, communicating over CAN and drawing power via a single daisy-chain cable arrangement. This reduces load on the vehicle’s CAN bus and allows advanced diagnostics, including hose burst detection, limp mode, and reporting of inlet, tank, load sense and work port pressures, spool position, consumed flow and oil temperature. Configuration is carried out using Danfoss’s Pro-FX® Configure software, which also supports factory-calibrated flow or pressure commands from either work port and easily changed operating parameters.

A CMA valve assembly (or “system”) is built from an inlet section (variable or fixed displacement) plus up to 8 work sections per physical block, with up to 15 work sections supported across a full network via the Valve System Module (VSM) and, where blocks are more than 6 m apart, a Valve System Extender (VSE).

Key Specifications

Configuration Overview

CMA systems are specified by selecting an inlet section model code and a work section model code for each section on the block, rather than choosing from a fixed list of standard part numbers. Key configuration choices include:

• Inlet type: variable displacement (load sensing) or fixed displacement
• Communication protocol: J1939 or CANopen
• Port types: SAE or BSP, in a range of sizes by port function
• Work section type (CMA90 only): CMA (independent metering) or CMT (pre-compensated dual double-acting)
• Spool bias: centre, tank, or pressure biased, selectable per work port
• Work port options: none, anti-cavitation valve, anti-cavitation valve with relief valve, or relief valve only, each with a selectable relief setting
• Manual override: none, or lever-operated override for emergency use, on the inlet conditioning valve and/or individual work sections
• Software package (CMA90): standard, advanced control, boom stability control, or all three combined

Advanced software features available depending on package selected include pressure- and flow-compensated control, Intellifloat, hose burst detection, load damping, electronic load sense, electronic pressure limiting, and boom stability control for actively damping oscillation in flexible services.

Typical Applications

• Concrete boom trucks
• Utility trucks
• Forwarders
• Agriculture tractors
• Drill rigs

Downloads

The following manuals are available from Danfoss for service and maintenance reference:

• Danfoss CMA Advanced Sectional Mobile Valves: Technical Catalog