What do the Probe LEDs mean?

What you may observe

You may notice one or more of the following:

• the blue LED is solid

• the green LED turns on during sampling

• the orange LED is solid

• the orange LED flashes

• the LEDs turn on one by one during startup

• the blue LED flashes and then turns off if network connection is lost or changing state

What each LED usually means

Blue LED

The blue LED relates to network connection.

• Solid blue: the Probe is connected to the Pulsenics Dashboard

• 3 quick flashes: the Probe is trying to connect

• 1 quick flash: the Probe has received communication

• 3 flashes speeding up: the existing connection is closing or has been interrupted

Green LED

The green LED relates to signal activity.

• Solid green: the Probe is actively performing EIS or signal injection, including 0 A signals

• 1 slow flash: the Probe has received a control action

• during repeated sampling, the green light may turn off when one sample finishes and turn back on when the next sample begins

Orange LED

The orange LED relates to warnings or stop conditions.

• Solid orange: the E-Stop is enabled or the EIS enable switch is in the off position

• 2 quick flashes: a warning-level message has been triggered

• 3 slow flashes: an error-level message has been triggered

Normal behaviours

The following are generally normal:

• on startup, the LEDs turn on one by one, then turn off together

• the blue LED may flash while the Probe is connecting

• the green LED may turn on only while sampling is active

• the green LED may turn off between samples

• a brief change in LED state while sending commands or starting a measurement can be expected

Patterns that usually need attention

These patterns usually mean you should check something before continuing:

• solid orange: check whether the E-Stop is enabled or the EIS enable switch is off

• orange flashing repeatedly: review any warning or error messages shown in your interface

• blue connection activity followed by loss of blue: check network connection stability

• green not appearing when you expect sampling to be active: confirm that sampling actually started

• LED pattern seems unusual or does not match the common behaviours above: record it and contact Pulsenics

What to check first

Start with the simplest checks:

1. confirm whether the Probe has finished booting

2. confirm whether the E-Stop is enabled

3. confirm whether the EIS enable switch is in the correct position

4. confirm whether the Probe is connected to the intended network

5. confirm whether sampling was actually started

6. review any warning or error messages shown in the Dashboard or control interface

When to contact Pulsenics

Contact Pulsenics if:

• the orange LED stays on and you are not expecting a stop condition

• the Probe never appears to finish booting

• the Probe is not staying connected

• sampling should be active but the green LED behaviour does not match what you expect

• you see repeated warning or error flashes

• the LED pattern does not match the descriptions above and the issue persists

What to send support

When reporting an LED-related issue, it is most helpful to include:

• what you were trying to do

• what you expected to happen

• what actually happened

• when it happened, including timezone

• any warning or error messages

• a photo or short video of the LEDs

• whether the issue is constant or intermittent

• what you have already tried

Article status

This is a living reference article for common Probe LED behaviours. Additional interpretations can be added over time as more support patterns are identified.