A commercial controls team needed two Trane SC controllers exposed over Modbus TCP to a downstream PLC. Chipkin QuickServer turned the BACnet/IP data into one PLC-facing register model and helped keep the commissioning window on track when the final controller-to-point split had to be confirmed in the field.
This case is useful because multi-device BACnet/IP to Modbus TCP projects often look simple until the PLC handoff depends on exact point ownership across more than one controller. The value was not just protocol conversion. It was getting the Trane SC controllers represented as one clean Modbus TCP interface the commissioning team could use immediately.
At a Glance
- Industry: HVAC / building automation controls
- Customer: Commercial controls integrator
- Facility type: Controller-to-PLC integration project
- Client role: Field controls technician and service manager
- Project scale: 2 Trane SC controllers and 11 final mapped points
- Protocols: From: BACnet/IP -> To: Modbus TCP
- Chipkin product: Chipkin QuickServer FS-QS-2010
- Project start: September 2022
- Internal reference: FSE15114
Architecture: Trane SC-1 and SC-2 controllers -> BACnet/IP -> Chipkin QuickServer -> Modbus TCP PLC
BACnet/IP to Modbus TCP Challenge
The upstream/server side was a pair of Trane SC controllers serving data over BACnet/IP. The downstream/client side was a GE PLC that needed the same information presented as Modbus TCP registers.
The real challenge was not basic connectivity. It was collapsing two BACnet/IP devices into one PLC-facing register model without losing the per-controller ownership that shaped the final point list. Five points belonged to one controller and six to the other, so the field handoff depended on confirming the split cleanly during commissioning.
That made the project a practical multi-device protocol conversion exercise rather than a one-box gateway demo. The PLC team needed one stable Modbus TCP handoff they could trust in the live install window.
Why Chipkin
This was a strong fit for Chipkin because the problem was not generic protocol conversion. It was multi-device point ownership, BACnet instance handling, and downstream Modbus mapping under live commissioning pressure. Chipkin QuickServer provided the gateway path, and Chipkin support helped the field team lock in the final controller-to-point split fast enough to keep the installation moving.
That matters in PLC handoff projects because a small mapping error can ripple into every downstream register assumption.
The Solution
Chipkin configured the QuickServer to read from two Trane SC BACnet/IP devices and serve the result as a single Modbus TCP endpoint for the PLC. The customer supplied the two BACnet device instances, and the final intended scope was eleven points total: five from SC-1 and six from SC-2.
When the site confirmed the final controller-to-point split during commissioning, Chipkin aligned the QuickServer file the same day and re-issued the validated map during a live support call. That kept the team focused on the real handoff requirements instead of losing the install window to point ownership ambiguity.
The result was a cleaner PLC-facing register model and a faster recovery during installation.
For another project where Chipkin kept a live controls commissioning window on track, see the EtherNet/IP to BACnet/IP PLC Alarm Integration case study.
Trane Controller Integration Results
The project delivered a working BACnet/IP to Modbus TCP handoff for a two-controller deployment.
Project proof points:
- 2 Trane SC controllers were mapped into one QuickServer integration.
- 11 final points were exposed after the per-device split was corrected.
- The final controller-to-point split was aligned the same day it was confirmed during installation.
- The field visit stayed productive because the corrected file was delivered during the commissioning window.
Before: the PLC team had two BACnet/IP controllers but no single confirmed Modbus TCP handoff they could trust at install time. After: one QuickServer endpoint presented the validated eleven-point split to the GE PLC in time for commissioning.
The technician’s response captured the turnaround:
“Awesome thank you! I will let you know if I need any help, hoping to get this set up next week.”
— Controls technician, commercial HVAC integrator
Have a Similar BACnet-to-Modbus Project?
Need to expose BACnet/IP controller data to a Modbus TCP PLC without losing time to point-map errors during installation? Chipkin can help with QuickServer configuration, per-device mapping, and fast commissioning support. Tell us about your project.
Frequently Asked Questions
Can QuickServer expose Trane SC controller data to Modbus TCP?
Yes. In this deployment, QuickServer read the two Trane SC controllers over BACnet/IP and exposed the final point set to the PLC over Modbus TCP.
Can multiple BACnet/IP devices be combined into one Modbus TCP handoff?
Yes, but the point ownership has to be modeled correctly. This case study shows why a two-device mapping can fail if the gateway treats every point as if it belongs to both upstream devices.
Can Chipkin fix a point-map error during commissioning?
Yes. The project recovered because Chipkin corrected the duplication issue during the live installation window instead of forcing the customer to wait for a later return visit.