BACnet MS/TP DIP Switch Address Calculator | 0–127

BACnet MS/TP DIP Switch Address Calculator

Convert a BACnet MS/TP MAC address into a seven-bit DIP switch pattern. Choose the correct profile, enter an address, or click switches to work in reverse.

Interactive seven-switch bank: select an individual switch to change the calculated address.

MAC Address 37
7-bit Binary 0100101
ON Switches SW1, SW3, SW6
The pattern is calculated for the selected profile.
Switches other than the seven address bits can select other functions. Do not change them without consulting your exact equipment manual.

How to Use This BACnet Address Calculator

  1. Choose a profile. Generic displays binary mathematics only. The manufacturer profiles are limited to the models named in the selector.
  2. Enter a MAC address. Type a whole number between 0 and 127 and select Calculate. The device profile applies additional restrictions.
  3. Read the switch chart. SW1 has a weight of 1, SW2 is 2, and so on through SW7 at 64.
  4. Set the equipment only after checking its manual. Confirm numbering, physical ON orientation, separate mode switches, and whether power must be removed before adjustments.

The interactive bank also works backward: click a switch to toggle its mathematical bit. The address and binary output update immediately. This does not communicate with or program a real BACnet controller.

SwitchBinary weightExample address 37
SW11ON
SW22OFF
SW34ON
SW48OFF
SW516OFF
SW632ON
SW764OFF

Worked example: Address 37 = 32 + 4 + 1. In an LSB-first seven-bit bank, turn on SW6, SW3, and SW1. Leave the remaining address bits off. The seven-bit binary representation is 0100101 when shown from most significant to least significant bit.

Why BACnet Device Profiles Matter

BACnet MS/TP is commonly used by building automation equipment such as controllers, gateways, VAV systems, and field devices. A MAC address identifies a node on its local MS/TP segment. Devices on the same segment cannot share the same active address without causing communication problems.

Generic binary profile: This is an arithmetic reference for seven sequential weights of 1, 2, 4, 8, 16, 32, and 64. The 0–127 range is mathematical, not proof that an arbitrary controller permits all values.

Johnson Controls SC-Connect: The manufacturer’s SC-Connect documentation specifies using the first seven of eight DIP switches to set an MS/TP MAC address from 1 through 127. The calculator does not claim that the eighth switch is an address bit or prescribe its position. This profile must not be generalized to every Metasys, Verasys, or Johnson Controls model.

Schneider Electric GWNP: The GWNP installation instructions use address switches 1–7 with binary weights 1–64. The eighth switch toggles communications protocol, and OFF selects BACnet for this particular model. BACnet address 0 is permitted by the GWNP instructions, while Modbus address 0 is not an individual Modbus address. Do not apply the protocol switch rule to unrelated Schneider devices.

Field safety: Treat these settings as a planning aid. Some controllers reserve particular MAC values, use other bit orders, or apply the changes only after restart. Follow the manufacturer’s commissioning and isolation procedures, especially around energized HVAC control panels.

BACnet MAC Address vs Device Instance

The MS/TP MAC address identifies the node on its physical MS/TP segment. A BACnet device instance is a different identifier used at the BACnet application level. Changing a DIP switch MAC setting does not necessarily set the BACnet device instance to that same number. For example, Johnson Controls documents an SC-Connect automatic instance method based on a separate formula.

Common Reasons a New Address Does Not Work

For systematic diagnosis of MAC conflicts and devices that drop offline, see our BACnet MS/TP Duplicate MAC Address Troubleshooting Guide.

  • Duplicate MAC address: Two devices may have the same address on the same MS/TP segment.
  • Wrong profile: Switch number 8 may control protocol, mode, or another feature.
  • Physical ON direction misunderstood: Compare the device’s ON marking with the actual lever direction.
  • Settings have not been applied: Consult the manual for power-cycle or commissioning requirements.
  • Network issue unrelated to the address: Wiring, baud-rate mismatch, termination, or bus configuration may be responsible.

For a different serial protocol, use our Modbus DIP switch address calculator. For HVAC configuration context, see the HVAC DIP switch setting calculator. These tools are not interchangeable with a model-specific BACnet manual.

BACnet address planning

Before applying a DIP pattern, understand the difference between a local MS/TP MAC address, Device Object instance and Max Master: BACnet MAC vs Device ID vs Max Master explained.

Frequently Asked Questions

Can I use this calculator for any BACnet controller?

No. The generic pattern only shows seven-bit binary math. Use the specific profile only for the named device, and verify your exact model’s DIP bank in its current manual.

Is BACnet MAC address 0 valid?

It depends on the device and bus setup. The Schneider GWNP documentation allows 0 in BACnet mode, while the Johnson Controls SC-Connect range covered here begins at 1.

What switches are ON for BACnet address 37?

For the seven-bit layout defined here, SW1, SW3 and SW6 are ON because 1 + 4 + 32 = 37.

Is switch 8 always set to OFF?

No. On the named Schneider GWNP, OFF on switch 8 selects BACnet protocol. Other controllers may use switch 8 differently. Consult the exact manufacturer’s diagram.

Why is a seven-bit switch bank limited to 127?

Seven binary bits represent values from zero through 2 to the power of seven minus one, or 127. Many real BACnet devices impose additional address restrictions.

Official Documentation and Sources

Independent educational calculator. Not affiliated with, endorsed by, or a replacement for any manufacturer. Reviewed October 2026.