Passive 4-20 mA Loop Display - Green LED is a passive loop display for 4-20 mA signals designed for compact Ø 22.5 mm panel mounting. It provides a 4-digit LED readout with programmable scaling and two MOSFET alarm outputs for HI/LO limit signalling.
🔧 Technical Highlights:
- Input: 4-20 mA (fixed), loop powered, voltage drop < 6 V
- Display: 4-digit 7-segment LED, 14 mm digit height, green display
- Scaling: Programmable projection for 4-20 mA, range -999 to 9999, decimal point adjustable in menu
- Linearization: 50-point linear interpolation (via OM Link microUSB)
- Accuracy: ±0.15% of range + 1 digit (for projection -999 to 1999); TK 50 ppm/°C
- Update rate: 0.1-100 measurements/s; overload capacity 2x
- Alarm outputs: 2x Power MOSFET, 30 VDC / 0.5 A; hysteresis band and switching delay ±99.9 s
- Connections: Terminal 1 = Input -, Terminal 2 = Input +, Terminal 3 = GND (outputs), Terminal 4 = LOW MOSFET, Terminal 5 = HIGH MOSFET; 0.2-1.3 mm2
- Panel mounting: Ø 22.5 mm cutout; IP65 front panel only
- Dimensions: 51.5 x 29.2 x 79 mm (W x H x D)
- Material: Noryl, incombustible UL 94 V-1
- Environment: -20 to 60°C operating; -20 to 85°C storage; EMC EN 61326-1
✅ Benefits:
- Loop-powered design simplifies installation in existing 4-20 mA transmitter loops.
- Compact Ø 22.5 mm mounting suits mosaic and signalling panels.
- Two MOSFET outputs enable HI/LO threshold signalling without relay modules.
- Fast update rate supports dynamic process indication.
- USB configuration (OM Link microUSB) supports setup archiving and firmware updates.
🚀 Applications:
- Local indication of 4-20 mA transmitters for pressure, level, flow and temperature (via transmitter).
- Alarm threshold signalling for pumps, tanks and process skids.
- Retrofit indication where no auxiliary supply is available.
- OEM control panels requiring compact current loop indication.
Accurate loop-powered indication with compact mounting and built-in MOSFET outputs for industrial 4-20 mA loops.
FAQs
- Q: How is the OMM 335PAS powered and what is the loop burden?
A: The indicator is powered directly from the 4-20 mA loop. The voltage drop across the instrument is less than 6 V. - Q: How do I wire the 4-20 mA input and the two alarm outputs?
A: Connect the 4-20 mA loop to terminals 1 (Input -) and 2 (Input +). The alarm outputs are power MOSFETs: terminal 5 = HIGH, terminal 4 = LOW, and terminal 3 = GND common (30 VDC / 0.5 A max).