Overview
This guide explains how to connect CoolPlugs to a CoolMaster, CoolMasterPRO, or CloudBox using the P-Bus (L3) line. You will configure the L3 port on the device's touchscreen and daisy-chain your CoolPlugs using the correct wiring polarity.
For full product specifications, see the CoolPlug Product Submittal.
Before You Begin
- Ensure you have physical access to the CoolMaster, CoolMasterPRO, or CloudBox touchscreen.
- Use 2-wire, shielded, twisted pair cable, 20–24 AWG for all P-Bus wiring.
- Do not wire the daisy chain in a loop — it must be a straight chain.
- Know your device's maximum CoolPlug capacity before wiring:
- CoolMaster: up to 32 CoolPlugs per P-Bus line
- CoolMasterPRO / CloudBox: up to 64 CoolPlugs per P-Bus line
Note: A CoolMaster can support more than one CoolPlug P-Bus daisy-chain. Ports L4, L5, L6, and L7 can also be configured for CoolPlugs in addition to L3.
Steps
Step 1 — Enable the P-Bus (CH) on Line 3
- On the CoolMaster touchscreen, navigate to Settings.
- Select HVAC Lines.
- Select L3.
- Set the L3 protocol to CH.
- Reset the device when prompted.
For a video walkthrough of this step, see: How to Activate Line 3 on a CoolMaster.
Step 2 — Wire the CoolPlugs in a Daisy Chain
Connect all CoolPlugs in series (daisy chain) back to the L3 port on your device, observing the following polarity mapping:
| CoolPlug Terminal | CoolMaster L3 Terminal |
|---|---|
| A | 1 |
| B | 2 |
| – (Ground) | – (Ground) |
The daisy chain runs as follows:
CoolPlug [A] → CoolPlug [A] → CoolPlug [A] → [1] of CoolMaster L3 CoolPlug [B] → CoolPlug [B] → CoolPlug [B] → [2] of CoolMaster L3 CoolPlug [–] → CoolPlug [–] → CoolPlug [–] → [–] of CoolMaster L3
Warning: Do not wire the daisy chain in a loop. Looped wiring will cause communication errors on the P-Bus.
CoolMaster — daisy chain diagram (max 32 CoolPlugs):
CoolMasterPRO / CloudBox — daisy chain diagram (max 64 CoolPlugs per Line):
For a video walkthrough of this step, see: Connecting and Setup of a CoolPlug to a CoolMaster.
Expected Result
Once L3 is configured as CH and all CoolPlugs are wired correctly, the CoolMaster (or CoolMasterPRO / CloudBox) will detect and communicate with each CoolPlug on the daisy chain. The connected units should appear in the device's unit list, and are now ready for integration into a HomeAutomation, and/or into a BMS, and/or into the CoolAutomation Cloud Apps.
Need Help?
If your CoolPlugs are not detected after completing these steps, please contact CoolAutomation Support for assistance.