Hydac HDA 7476-A-1000-000 OEM Pressure Transmitter, 1000 psi

Miniature OEM transmitter for tight cavities

The Hydac HDA 7476-A-1000-000 (HYDAC part number 920030) is the 1000 psi version of the HDA 7400 series, a very compact transmitter designed for OEM machines and for mounting in confined cavities, for example in valve manifolds on mobile equipment. The body weighs only about 60 g, compared with roughly 145 g for the HDA 4700.

A thin-film strain gauge on a stainless steel membrane forms the sensor, with a two-wire 4 to 20 mA output through an M12x1 four-pole plug. The mechanical connection is the 9/16-18 UNF 2A male (SAE-6) port.

Technical specifications

Where the HDA 7400 fits

The small body is the reason to pick this series. It fits into manifold blocks, valve stacks and compact power packs where a 27 mm hex body would not. The trade-off against an HDA 4700 is a lower accuracy figure (0.5 % FS typical against 0.25 %) and a 2 ms rise time. For machine control, load monitoring and pump pressure feedback that is usually acceptable.

Order code

The code HDA 7 4 7 6 – A – 1000 – 000 (PSI) reads as follows: 7 is the SAE-6 thread, 6 the M12x1 four-pole plug, A the 4 to 20 mA signal, 1000 the range in psi, 000 the standard modification. Available ranges are 300, 500, 750, 1000, 1500, 3000, 5000, 6000 and 9000 psi, and 0 to 10 V (B) is offered. Pin 1 is signal plus and pin 3 signal minus on the current version. The matching M12 cable is an accessory, so order the connector separately. Datasheet: HYDAC USA edition E 18.326.2.

Apply sealing at the SAE-6 O-ring face rather than with thread tape, route the cable so the M12 plug is not stressed, and keep the signal cable away from heavy power lines. In a manifold cavity, check the depth and the sealing face against the datasheet drawing, because the SAE-6 port needs the full O-ring seat to reach the stated pressure rating. Where the fluid is not mineral oil, confirm FKM compatibility, and ask the supplier about alternatives if needed.

The compact body is intended for installation directly in a hydraulic block or manifold, so check the cavity drawing and plan the cable routing before ordering. Quote the full code, including the 1000 psi range, so that the right output signal and connector are supplied.

Selection checks for the 1000 psi range

Choose the range from the real working pressure of the circuit, not from the relief valve setting alone. Pressure spikes from valve switching, cylinder end stops and pump start-up can be far higher than the steady reading, so compare the expected peaks with the 2900 psi overload figure in the table. If peaks regularly approach that value, a higher range from the list above, or damping in the circuit, is the safer route. On the other hand, a range far above the working pressure wastes resolution, so the 1000 psi version is best matched to circuits that spend most of their time in the upper part of that span.

Check the loop electrics as well. The permitted load resistance formula in the table ties the maximum receiver input resistance and cable resistance to the supply voltage, so a controller analog input with a high burden on a low supply voltage may leave too little margin. Work through the formula with the actual supply before wiring.

Fitting the transmitter in the manifold

Clean the port and the sealing face before installation, lightly lubricate the O-ring with the system fluid and tighten to the torque given in the table using a spanner on the transmitter body, not on the connector. Bleed trapped air from the port where possible, because an air pocket can make the reading sluggish or noisy. Support the cable close to the plug so that vibration from the machine is not passed into the connector.

Commissioning and signal checks

With the system depressurised, the output should sit at the 4 mA zero; a current well below that usually indicates a wiring or supply fault rather than a sensor problem. Raise the pressure in steps and compare the transmitter reading with a calibrated reference gauge on the same circuit. Set alarm and trip thresholds in the controller, and confirm that a broken wire produces a fault indication rather than an apparently valid low reading.

Operating in hot, dusty GCC conditions

Mobile machines and power packs in Oman often see high ambient temperatures together with hot hydraulic oil, so compare both the ambient and the fluid temperature at the mounting point with the limits listed above. Mounting the transmitter away from direct radiant heat from engines or exhausts helps. The IP 67 rating depends on a suitable mating connector being properly fitted, so keep the connector seal intact and do not leave the plug open to dust and moisture for long periods. Fine sand and dust around the port should be cleaned away before the transmitter is removed, so that dirt does not enter the hydraulic system.

Maintenance practice

Include the transmitter in periodic calibration checks against a reference gauge, especially on circuits used for load monitoring or safety functions, and record the readings to follow drift over time. Inspect the cable and connector for abrasion and heat damage during routine machine servicing.

Documents and quotation

The datasheet is attached. Please give the full code, the fluid and your quantity. Related: our pressure instrumentation range.