Products > Communications

AC-PRO®/ZERO-Hertz® Communications Setup

MODBUS communication setup

AC-PRO trip units with the communications option have an RS485 port and use the industry standard Modbus RTU protocol. Up to 32 trip units can be connected on one twisted pair. Each AC-PRO is programmed with a unique address. Data can be requested from the trip units and commands can be sent to the trip units from the HMI system. A locally installed Local Communications Interface (LCI) can be used to view the data from each AC-PRO trip unit. A host PC running a HMI application collects information from the communicating AC-PRO trip units. The Modbus driver in the HMI interrogates each trip unit individually and reports that information to the HMI application on a continual basis.

Commands sent from HMI system to any AC-PRO or ZERO-Hertz through communications

• New settings
• Clear last trip data, trip log & kwh
• Clear trip alarm
• Force trip breaker (if enabled in trip unit)
• Energize 2 user defined auxiliary relays

PT Module Function PT Module

• Provides voltage information for power calculations in the AC-PRO trip unit
• Allows the AC-PRO trip unit to communicate when there is less than 10% breaker current or when the breaker is open


LCI® FunctionLCI

• Provides local access to data from all connected AC-PRO trip units
• Provides an Internet port



Information available from each AC-PRO or ZERO-Hertz through communications

• Currents, 3-Phase & Ground Fault
• Voltages, 3-Phase L-L & L-N
• Protective settings
• Alarm status
• Last trip data including currents
• Trip log
• Breaker open or closed status

System Requirements Provided by URC

• AC-PRO retrofit kit with communication option and PT module

Provided by Others

• Shielded twisted pair for RS485 connection
• CAT 5 cable for LAN connection
• HMI software


Screen Shot of a Demonstration Spreadsheet Using the AC-PRO Communications Package

AC-PRO Communications Demo Page

This spreadsheet shows the types of information that is available from the AC-PRO communications package. Utility Relay Company does not have a software package that can be used in the field. The software that we do have is used to demonstrate the capabilities of our system to any potential users.

AC-PRO Compatibility with HMI Software

AC-PRO communications can be integrated into various industry-standard HMI systems that have a Modbus RTU driver. A few examples are:

•  Schneider Electric ION-Enterprise™ •  Schneider Electric SMS-3000™
•  Wonderware’ s INTOUCH™      •  Power Measurements PEGASYS™
•  Siemens WinPM™  

Please contact us if you need more information about the communication options available from Utility Relay Company.