What the relay interface does
The documented arrangement uses the stop output to energize a small 12 V reed-relay coil. The relay’s normally closed contact then provides the required N/C E-stop connection. This separates the stop output circuit from the contact circuit, but the evidence does not identify the output terminals, switching topology, coil-current limit, contact rating, or safety classification.
Wiring concept
12 V coil circuit:
+12 V ---- reed-relay coil ---- stop-output switching path ---- 0 V
| |
+-- diode -+
Isolated contact circuit:
E-stop input ---- relay N/C contact ---- E-stop returnConnect the diode directly across the coil in reverse bias during normal operation: its cathode faces the coil’s positive side and its anode faces the negative or switched side. When the output turns off, the diode suppresses the coil’s inductive kickback. Do not copy the shown supply polarity until the stop output’s sourcing or sinking behavior is confirmed from the applicable manual.
Component and output checks
| Item | Evidence-supported requirement | Information still required |
|---|---|---|
| Relay coil | Small 12 V reed relay | Coil current and resistance |
| Suppression | Reverse-biased diode across the coil | Diode current and voltage ratings |
| Stop output | Drives the relay coil | Sourcing/sinking topology and allowable load |
| Relay contact | N/C contact used for the E-stop connection | Contact voltage, current, and required safety classification |
Confirm that the relay coil current does not exceed the stop output rating. Also verify that the N/C contact is suitable for the connected input circuit. The available evidence does not establish that the reed relay or stop output is safety-rated, so obtain the required safety information before using this arrangement as a machine protective function.
Commissioning procedure
- Identify the stop output terminals and confirm whether the output sources or sinks current.
- Verify that the output can drive the selected 12 V reed-relay coil.
- Wire the coil through the stop output and install the reverse-biased diode directly across the coil.
- Wire the relay’s N/C contact into the E-stop input circuit.
- Operate and release the stop command while checking relay state, N/C contact continuity, and correct input indication. Confirm that removing coil power returns the contact to its normally closed state.
FAQ
How do I connect a 12 V reed relay to the Viper stop output?
Connect the 12 V coil through the stop output’s switching path, then use the relay’s isolated N/C contact for the E-stop connection. Confirm the output topology and coil-current capacity before wiring.
Which way does the diode go across the relay coil?
Install it reverse-biased during normal operation: cathode toward the coil’s positive side and anode toward its negative or switched side. Place it directly across the coil.
Can any 12 V reed relay be used for the E-stop connection?
No. Verify coil current against the stop output rating and verify the N/C contact’s electrical and required safety ratings. Those ratings are not provided in the available evidence.