Valmet ATB16‑4 16‑Channel Relay Card Controller Board – Module 22195028

The Valmet ATB16‑4 is a 16‑channel relay output module designed for high‑reliability digital control in industrial automation systems. Identified by part number 22195028, this controller board provides galvanically isolated relay contacts that can switch AC or DC loads, making it suitable for driving solenoids, contactors, alarms, and pilot lights. It is a standard component in the Valmet DNA and Metso distributed control platforms, offering robust performance in demanding mill and plant environments.

Relay Output Specifications

Each of the 16 channels features a single‑pole double‑throw (SPDT) relay with a contact rating of 250 V AC / 30 V DC at 5 A (resistive load). The relays are capable of switching inductive loads with appropriate snubber circuits; the board includes integrated flyback diodes for DC loads. Contact material is silver‑alloy with gold plating, ensuring low contact resistance and long life (mechanical life >10⁷ operations). The output status is indicated by individual green LEDs on the front panel.

Isolation and Protection

The relay contacts are galvanically isolated from the logic circuit by a 1500 V AC isolation barrier. Each output channel is protected against transient overvoltage and has a built‑in fuse (field‑replaceable) for overload protection. The board also includes a common fault detection circuit that monitors coil supply voltage and relay coil continuity; any failure is reported via a red LED and a diagnostic bit on the communication bus.

Communication and Control Interface

The ATB16‑4 communicates with the host controller via the Valmet backplane bus, which supports both cyclic and acyclic data exchange. The module uses a 16‑bit output data word, where each bit corresponds to one relay channel. It also supports a read‑back feature, allowing the controller to verify the actual state of each relay (coil energized/de‑energized). The module can be configured for fail‑safe operation – in case of communication loss, all relays can be set to a predetermined safe state (either all open or all closed) via a hardware jumper.

Hardware Design and Mounting

The board is a 6U x 4HP Eurocard (233 mm x 20 mm) with a 96‑pin DIN connector for backplane connection. The front panel includes a handle for easy insertion and extraction. Field wiring is terminated on a removable 50‑pin screw terminal block that accepts wires up to 2.5 mm². The module draws power from the backplane: +5 V at 200 mA and +24 V at 100 mA (for relay coil drive). An external 24 V supply for the relays is not required as the board generates its own isolated coil voltage.

Environmental and Reliability Data

Operating temperature range is 0 °C to +55 °C; storage from ‑40 °C to +85 °C. Humidity tolerance is 10‑95 % non‑condensing. The board is conformal coated for protection against dust and chemical vapors. It meets IEC 61131‑2 and EN 61010‑1 standards, and carries CE and UL approvals. MTBF is estimated at 1.2 million hours at 40 °C.

Installation and Commissioning

Install the board into a compatible Valmet subrack, ensuring proper alignment with the backplane. Connect the field wiring to the terminal block, observing polarity for DC loads (common terminal provided). Use the engineering tool to assign the output addresses and configure the safe‑state settings. Perform a loop test by commanding each relay on/off and verifying the contact closure with a multimeter. The board also supports a self‑test mode that cycles all relays to check for stuck contacts.

Typical Applications

This relay card is extensively used in paper mills for controlling motor starters, valve actuators, and heating elements. In chemical plants, it is employed for sequencing batch operations and alarm annunciation. Its 16‑channel density makes it ideal for applications requiring multiple discrete outputs in a compact form factor.

Maintenance and Troubleshooting

Periodic inspection includes checking the LED indicators and verifying the fuse integrity. If a relay fails to operate, check the coil voltage and the contact condition. The board provides diagnostic feedback via the communication bus; a stuck‑relay detection algorithm can be enabled in the controller. Spare fuses and replacement relays (soldered on PCB) are available; however, field replacement of individual relays is not recommended – the entire board should be swapped if multiple relays fail.

Compatibility and Upgrades

The 22195028 module is backward‑compatible with earlier ATB16‑4 versions but offers improved EMC filtering and faster relay response time (typical 5 ms). It is fully compatible with Valmet DNA versions 5.0 and above.

Conclusion

The Valmet ATB16‑4 16‑channel relay card (module 22195028) provides a reliable, high‑density solution for digital output control. Its robust isolation, diagnostic features, and simple integration make it a cornerstone of discrete control in industrial automation.