The ESM-2 is an environmental sensor that provides data to its registered controller via BACnet MS/TP. This protocol requires each sensor to have a unique MAC address that is used to identify the sensor along the MS/TP chain. Common issues that will prevent data from populating from an ESM-2 are as follows:
Duplicate MAC Address Within the MS/TP chain
If one has recently added an ESM-2 to an existing MS/TP chain, and one does not see the new sensor register to the controller or lose communication to other devices across the MS/TP chain, then there is likely a duplicate MAC Address in the chain. In some cases, one may even see a new sensor that registers to the controller but is mirroring the exact same data as an existing sensor. Each ESM-2 sold arrives in a box noting what MAC Address the sensor has been set to. Confirming that there is no MAC address conflicts across the chain by referencing the MAC addresses set for each ESM-2 would rule out this possibility.
Loose Signal Wire along the MS/TP chain
Since BACnet MS/TP is a serial communication protocol, it is important to ensure the terminations along the MS/TP chain are not loose in order to have consistent communication. The most common cause of loss of communication across an MS/TP chain is a loose signal wire along the chain resulting in communication failing as data is passed along the chain. Checking each termination to ensure that there is not a loose signal wire is the primary way that one can resolve this issue.
No End of Line Resistor at the end of MS/TP chain
BACnet MS/TP communication relies on passing a token back and forth along the chain. When a resistor is placed at the End of Line, the increase in resistance signals this token to return back towards the point of origin. In most cases, an End of Line resistor is not needed within MS/TP chains, but does reduce latency in communication across the MS/TP chain. If the latency within an MS/TP chain is high, adding in and End of Line resistor can resolve issues with timeouts in communication across the MS/TP chain. The specific resistors used within these MS/TP chains are a 0.5W 120 Ohm resistor.
Incorrect Wiring
If one is not seeing any data from an ESM-2 and there is no duplicate MAC address or loose signal wire, then it is likely that there may be incorrect terminations across the MS/TP chain. Note that back-feeding 24VDC on the communication wires of the ESM-2 can damage the sensor and upstream inputs, so one must ensure that the sensors are being wired up correctly during their installation.
For environmental panels, the documentation below can serve as a good reference for wiring:
Article:
https://knowledgebase.growlink.com/knowledge/esm-2-quick-start-guide-1
Wiring Diagram from Article:
https://3941033.fs1.hubspotusercontent-na1.net/hubfs/3941033/ESM2_Wire_Diagram_1.2%20(2).pdf
For Connect Controller customers, the documentation below can serve as a good reference for wiring:
Article:
https://knowledgebase.growlink.com/knowledge/connect-controller-manual-controller-only#ESM-2_Wiring
Wiring Diagram from Article:
https://3941033.fs1.hubspotusercontent-na1.net/hubfs/3941033/Knowledge%20Base%20Assets/Connect%20ESM-2%20Wiring%20Rev%20A.pdf
Values Not Updating
In some rare cases, the ESM-2 will stop updating its readings. This is most commonly caused by the sensor no longer responding to requests for data and the last reported data being held on the front-end. The most common way to resolve this behavior is to power-cycle the sensor by unseating it from its wiring harness, waiting 30 seconds, followed by re-seating the sensor into its wiring harness. This simultaneously power-drains the sensor and ensures the sensor is properly seated in its wiring harness to ensure appropriate communication.
Offsetting Sensor Readings
The Temperature, Humidity, and CO2 sensor readings on the ESM-2 can be offset within the Mobile App and Web Portal to closer match a third-party sensor. The resource below will illustrate how one can offset the sensor readings accordingly:
Portal 2.0:
Warranty Info:
Sensors sold have a warranty of 1 year from the date of receipt or date of registration, whichever occurs first. Further warranty information can be found at the link below:
https://www.growlink.ag/return-policy-1