Description
ifm AC5251 — Product Page
Product Overview
The ifm AC5251 is an AS-Interface AirBox designed to combine digital sensor acquisition and pneumatic valve control in a compact field-mounted unit. It provides four digital PNP inputs and one 5/2-way bistable spool valve. This arrangement is useful in automated machinery where several sensors monitor a station while a pneumatic actuator is controlled through the AS-i network. Rather than routing each sensor signal and valve command through separate centralized wiring, the AC5251 connects these functions to an AS-i installation through its flat-cable interface.
The four digital inputs accept compatible sensor signals and are supplied through the AS-i system. The manufacturer specifies a high-level input current of 6–10 mA, a low-level current of 0–2 mA, and a minimum high switching level above 11 V. The inputs have short-circuit protection. The pneumatic section uses a bistable 5/2-way spool valve, with two selectable pneumatic output functions. A bistable valve retains its last commanded spool position rather than returning automatically to a default position when the switching command is removed. This distinction matters when designing restart behavior, actuator positioning, and fault recovery.
For mechanical integration, the ifm AC5251 operates over a 3–8 bar compressed-air pressure range and provides a published flow rate of 500 L/min under specified test conditions. It accepts 8 mm pneumatic tubing and includes a manual override for commissioning and troubleshooting. The housing is rated IP65/IP67, subject to the specified installation and connector conditions, and the documented ambient temperature range is -10°C to +55°C. AS-i versions 2.11 and 3.0 are supported, including extended addressing mode.
The AC5251 should be selected by its complete functional specification rather than its model number alone. A replacement must match the required valve behavior, input arrangement, pneumatic pressure, tube size, AS-i profile, and mounting orientation. It is also important to check whether the application expects a bistable 5/2 valve or a monostable valve that returns to a defined position. These functions are not interchangeable without reviewing the actuator and machine safety design.
Product Introduction — Practical Field Focus
When a pneumatic cylinder does not move as commanded, the problem may involve the AS-i network, sensor inputs, compressed-air supply, tubing, or valve position. The ifm AC5251 combines four digital inputs with a bistable 5/2-way valve, allowing compatible sensors and pneumatic actuation to be integrated at the machine level.
Before replacement, verify AS-i addressing, valve switching behavior, available air pressure, tube connections, and the required restart state. During commissioning, test both valve positions and confirm that the actuator behaves as intended after power interruption or loss of a control command.
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Model | |
| Manufacturer | ifm electronic |
| Product category | AS-i AirBox |
| Digital inputs | 4 |
| Input circuit | PNP |
| Sensor supply | AS-i |
| Input voltage supply | 20–30 VDC via flat cable |
| High input current | 6–10 mA |
| Low input current | 0–2 mA |
| Minimum high switching level | Greater than 11 V |
| Input protection | Short-circuit protected |
| Pneumatic valve configuration | 1 × 5/2-way spool valve |
| Valve behavior | Bistable |
| Pneumatic output functions | 2, selectable NO/NC function |
| Actuator supply | AS-i |
| AS-i versions | 2.11 and 3.0 |
| AS-i profile | S-7.A.E |
| AS-i I/O configuration | Hexadecimal 7 |
| AS-i ID code | Hexadecimal A.E |
| Extended addressing | Supported |
| AS-i connection | Quick-mount flat-cable interface |
| Addressing | Dedicated addressing socket |
| Operating pressure | 3–8 bar (0.3–0.8 MPa) |
| Rated air flow | 500 L/min under specified test conditions |
| Pneumatic tube connection | 8 mm |
| Manual override | Available |
| Exhaust | Can be routed through a tube connection |
| Protection rating | IP65 / IP67 |
| Ambient temperature | -10°C to +55°C |
| EMC standards listed | EN 50295; IEC 61000-6-2 |
| MTTF | 258 years, as stated in the manufacturer’s data |
| Housing materials | PA and POM |
| Contact material | CuSn6 with nickel and tin plating |
| Mounting | Quick mounting; DIN rail mounting supported |
| Dimensions | 108 × 85 × 50 mm |
| Published weight | Approximately 292 g for the documented version |
The manufacturer’s documentation includes different weight figures for different catalog or mounting versions. Confirm the exact supplied configuration before using weight or mounting details for mechanical design.
IFM AC5251
Related Products
- ifm AC5253 — AS-i AirBox with a 5/2-way bistable valve and four digital inputs; uses an external 24 VDC supply arrangement rather than the ‘s AS-i-powered configuration.
- ifm AC5270 — AS-i AirBox with a 5/3-way valve and closed center position, for applications requiring a different pneumatic state.
- ifm AC5285 — AirBox with two 3/2-way monostable valves, for applications needing two separate switching functions.
- ifm AC5227 — AS-i AirBox with two 3/2-way monostable valves and two digital inputs.
- ifm E75232 — Pneumatic silencer accessory.
- ifm E75227 — Push-in T-fitting accessory.
- ifm E75229 — Push-in L-fitting for reducing tube connection size from 8 mm to 6 mm.
- ifm E75231 — Sealing plug for AirBox installations where the pneumatic function is not used.
Related AirBox models have different valve behavior, input counts, and power arrangements. Verify the complete configuration before considering one as a substitute.
Frequently Asked Questions
Q1. What is the function of the ifm ?
The combines four digital PNP inputs with one 5/2-way bistable pneumatic valve. It is used to integrate sensor feedback and pneumatic actuator control into an AS-i automation network.
Q2. Is the valve bistable or monostable?
It is bistable. The spool maintains its last commanded position rather than automatically returning to a default position when the switching signal is removed. The machine’s restart and fault-response behavior must account for this characteristic.
Q3. What AS-i versions does the support?
The manufacturer specifies AS-i versions 2.11 and 3.0, with extended addressing mode. Check the AS-i master configuration, profile, addressing, and network design before commissioning.
Q4. What air pressure is required?
The documented operating pressure range is 3–8 bar. Confirm the actual pressure at the module under flow conditions and ensure that the compressed air meets the manufacturer’s cleanliness and moisture requirements.
Q5. Can the be used outdoors or in a washdown area?
The module is listed with IP65/IP67 protection. That rating applies under the specified installation and sealing conditions; it does not automatically establish suitability for every chemical exposure, high-temperature washdown, or outdoor environment. Check the connector, flat-cable installation, pneumatic fittings, and environmental requirements.
Q6. What should be checked if the valve does not switch?
Check the AS-i supply and communication status, addressing, output command, compressed-air pressure, exhaust routing, tube connections, and manual override position. Confirm that the selected valve function matches the actuator’s required movement. Isolate pneumatic energy according to site procedures before disconnecting tubing or servicing the valve.
Q7. Is AC5253 a direct replacement for ?
Not automatically. Both have a 5/2-way bistable valve and four digital inputs, but AC5253 uses an external 24 VDC supply arrangement. Check power wiring, mounting, AS-i configuration, and the complete product documentation before substitution.
Q8. What should procurement verify for used or refurbished stock?
Request a clear label photograph, confirmation of the exact model, condition and connector details, functional test results, warranty terms, and confirmation that the pneumatic valve switches in both directions. Where possible, ask for evidence that the digital inputs and AS-i communication have also been tested. A generic “tested” description is not proof of full pneumatic and electrical functionality.
