DFB01 and PFB01 are precise frequency monitoring relays. The relays monitor their own power supply from 24 to 240 VAC. The advantage of using the latch function is that the relay can be kept energized even after the end of the alarm condition. Inhibit func- tion can be used to avoid relay operation when not desired (maintenance, tran- sitions). The LED's indicate the state of the alarm and the output relay.
The DFB01 and PFB01 relays monitor the frequency of their own power supply (24‑240 VAC) and provide over/under‑frequency protection. They feature adjustable upper and lower limits, programmable delay times, and selectable latching or inhibit functions, with LED indicators for power, alarm, and relay status.
The devices are offered in a DIN‑rail version (22.5 × 80 × 99.5 mm) and a plug‑in version (36 × 80 × 94 mm), each rated for 8 A SPDT output. Detailed wiring diagrams, DIP‑switch settings, and environmental specifications are provided for installation and maintenance.
| Supply voltage | 24 to 240 VAC |
|---|---|
| Frequency range | 50 – 60 Hz |
| Output relay | 8 A SPDT, N.D. or N.E. selectable |
| Mechanical life | > 30 × 10⁶ operations |
| Electrical life | = 10⁶ operations (at 8 A, 250 V, cos = 1) |
| Dielectric voltage | 2 kVAC (rms) / 4 kV (1.2/50 µs) |
| Housing dimensions (DIN‑rail) | 22.5 × 80 × 99.5 mm |
| Housing dimensions (Plug‑in) | 36 × 80 × 94 mm |
| Weight | ≈ 150 g |
| Operating temperature (DFB01) | -20 °C to 60 °C, RH < 95 % |
| Operating temperature (PFB01) | -30 °C to 80 °C, RH < 95 % |
| Approvals | UL, CSA, CE‑Marking |
They operate from 24 VAC up to 240 VAC.
The limits are adjusted with DIP switches 1, 2, 4 and the corresponding knobs; upper level is set with the upper knob (‑10 % to +100 % of range) and lower level with the centre knob (‑100 % to +10 %).
The DIN‑rail DFB01 operates from –20 °C to 60 °C, while the plug‑in PFB01 operates from –30 °C to 80 °C, both with relative humidity below 95 %.