Direct current (DC) sensor

The SENSE CUR 4600 or the clamp sensor

The CUR 4600 measures 'activity' based on direct current (DC) flowing through an electrical wire. If you want to know the utilization of your and/or the charging of your asset, you can do this with the SENSE CUR 4600.

The SENSE CUR 4600 is an externally sourced current clamp. The current clamp can detect if the battery of an asset is charging or discharging and communicates this information to the nearby tracker.

Use cases

The CUR 4600 measures 'activity' based on direct current (DC) flowing through an electrical wire. DC currents are typically flowing in and out of batteries. So, anything that has a battery pack and an exposed wire where the current is flowing through is a good candidate to monitor activity from.

Following assets typically meet these criteria:

• Cleaning machines
• Cleaning robots
• Electric Forklifts
• Electric Golf carts
• Solar batteries
• Backup/emergency batteries
• Anything that has a battery or works on DC power is a good use case

Setting expectations

To be clear on what the sensor does and doesn't, hereby a list of what the CUR 4600 doesn't provide:

• Don't expect to count the time of short current flows; because the measurement interval is 30 seconds, and the time reporting resolution is in minutes.
• Don't expect live current measurement (or any current measurement)
• Don't expect to see current vs time in a graph
• Doesn't measure voltages
• Doesn't measure usage of AC generators
• Doesn't measure any alternating current (AC)
• Don't use the sensor outdoor, these clamps are not IP rated
• Don't drop them, these clamps are made with fragile ferrite cores inside and will not survive a drop
• Don't hit them, these clamps are not IK rated
• Don't put the + and the – wire into the clamp at the same time, as the positive and negative magnetic fields (induced by the current flow) will cancel each other out., resulting in always measuring nothing!

How the sensor works

The split core design permits non-contact current measurements through magnetic field induction captured by a hall effect sensor. The sensor works without disconnecting the cable circuit for installation of the sensor.

Which data is captured

On the Sensolus platform we visualize following data:

Some more details:

• We can measure which direction the current is flowing and for how long ; so this usually translates to ‘time charging’ and ‘time used’. (for example: 2 types of activity); each direction uses one sensor slot, so only enable both if you need both (on the tracker profile configuration).
• The clamp will only increment the reported time if a current is above the filter threshold at the time of measurement. By default this is set to 1.8A in the forward direction and 0.5A in the backwards direction (arrow sticker indicates forward direction), anything below this threshold is ignored and will not increment the time counter.
• So when time does not increase we can interpret this as “no activity”
• Measurement interval is 30 seconds / reporting resolution is 1 minute
• The time count is persistent on the clamp, it will not wrap around, however the tracker is limited in it’s value
• Battery life is 5 year ‘guaranteed’ (up to 7 in ideal conditions – don’t count on it!)
• The filter thresholds can be configured for both directions from 0.5A till 19.9A (the clamp measurement maxes out internally at 20A)
• The clamp will not be damaged with currents up to 100A (internal measurement clamps at 20A)

Connecting the sensor to the tracker

The current clamp communicates over BLE with the (already installed) tracking devices which sends the information to the cloud. A sensor can be linked to a tracker using a mobile phone.