Key Technical Specifications
- Product Model: CONTRANS T TEU471
- Manufacturer: Hartmann & Braun (H&B)
- Product Type: Analog Signal Converter
- Input Signal: Thermocouple, RTD, or mV
- Output Signal: 4-20 mA (2-wire)
- Power Supply: 24 VDC Loop Powered
- Accuracy: ±0.1% of Span
- Isolation: 1500 VAC Input/Output
- Operating Temp: -20°C to +70°C
- Mounting: DIN Rail
Product Introduction
Ground loops in old control panels will ruin your day. I’ve spent hours chasing phantom noise on a 4-20 mA loop, only to find out a failing isolator was letting common-mode voltage bleed into the analog signal. The H&B CONTRANS T TEU471 was built specifically to stop that. It takes a raw thermocouple or RTD signal, isolates it with 1500 VAC dielectric strength, and pushes a clean 4-20 mA current back to the PLC.Engineers still hunt for these because they actually hold their calibration. With ±0.1% accuracy and a wide -20°C to +70°C operating range, the TEU471 doesn’t drift when the panel gets hot in July. Just be aware that H&B is legacy hardware now. This specific revision is notoriously picky about having a clean 24 VDC supply; if your power supply has ripple, it will show up as noise on the output. Otherwise, it’s a bulletproof piece of kit.
Quality SOP & Tech Pitfalls
The Lab Report: We don’t just ship these. Every TEU471 gets a visual check under magnification for cold solder joints or corroded terminals. We mount it on a live test rack, inject a 4 mA and 20 mA reference signal, and verify the output with a Fluke 115. We log the firmware revision and seal it in anti-static packaging.The Engineer’s Warning: Do not skip the DIP switch configuration check. The TEU471 uses physical switches to set the input type (TC, RTD, mV) and range. I once swapped a board for a guy who forgot to photograph his old switch settings. He spent four hours guessing input types while the plant was down. Also, watch out for ESD. These older H&B boards have basic input protection. A static shock from your finger during installation can fry the internal op-amps instantly. Always wear a grounding strap.
Installation & Configuration Guide
- Pre-Installation: ⚠️ Lock out and tag out the 24 VDC supply. Wait 60 seconds for capacitors to discharge. Take a high-resolution photo of the old module’s DIP switch positions and wiring.
- Removal: Label every wire with a sharpie. Press the DIN rail release tab with a flathead screwdriver and pull the module straight out. Do not pry it.
- Installation: Set the new TEU471 DIP switches to EXACTLY match your photo. This prevents 90% of startup failures. Slide the module onto the rail until it clicks. Reconnect wires per your labels.
- Power-On & Testing: Restore 24 VDC. Watch the LED boot sequence. Use a multimeter in series to verify the loop current matches your expected process value. Download or verify the PLC tag scaling.
Compatible Replacement Models
| Compatibility | Model | Notes |
|---|---|---|
| ✅ Drop-in Replacement | H&B TEU471 (Rev C) | 100% hardware match. Verify Rev C suffix. |
| ⚠️ Software Compatible | ABB INFI-CON IMPAC | Same 4-20mA output, but requires DIP switch reconfig. Est. 15 mins labor. |
| ❌ Hardware Mod Required | Siemens SITRANS TH400 | Requires new DIN rail adapter and rewiring. Advise against unless full panel upgrade. |
Frequently Asked Questions (FAQ)
Can I hot-swap this module safely?
No. The TEU471 is loop-powered. Pulling it while energized will arc the terminals and likely fry your PLC analog input card. Always kill the 24 VDC first.Is this the exact same as the TEU470?
Not quite. The 471 has updated isolation specs. You can use a 471 to replace a 470, but do not put a 470 in a slot that originally required a 471. Check the panel schedule.What happens if my 24V supply has ripple?
The output will jitter. The TEU471 needs clean DC. If your power supply is old and whining, replace it before you blame the converter.Do you have the original manual?
H&B manuals are tough to find online. We provide a digital PDF copy of the TEU471 wiring and DIP switch guide with every shipment.What if it fails in 6 months?
We back it with a 1-year warranty. If it dies under normal use, we replace it. But honestly, if it survives the first 30 days of operation, it’ll probably outlive the rest of the panel.Can I use this for a 3-wire RTD?
Yes, but you must wire the third wire to the designated compensation terminal. If you tie it to ground, your temperature reading will drift as the ambient panel temperature changes. Read the wiring diagram.
