APC ACRP500 User Manual

To configure Modbus, select the Administration tab, General on the top menu bar, and Serial Modbus 
on the left navigation menu. You can enable or disable Modbus, choose a baud rate, and specify a unique 
identifier.

Modbus defines a request/response message structure for a client/server environment. The APC 
implementation of Modbus uses Remote Terminal Unit (RTU) mode. You can use Modbus to view the 
cooling unit through your building management system interface. It is read-only.

•  The Modbus interface supports 3-wire RS-485 (D0, D1, and Ground). 
•  Modbus runs at 9600 or 19200 bps.

The Modbus register map for the cooling unit defines the data (type, location, and valid responses) 
available through Modbus. To download the latest Modbus register map, go to the APC Web site 
(www.apc.com), search by product, and click the documentation link. Click on the link to the register 
map in the list of documentation. Check the publication date at the start of the file.

Select the Administration tab, the General option on the top menu bar, and the Quick Links option on 
the left navigation menu to view the three URL links displayed at the bottom left of each page of the 
interface. 

By default, these links access the following Web pages:

•  APC’s Web Site: The APC home page. 
•  Testdrive Demo: A demonstration page where you can use samples of APC Web-enabled 

products.

•  APC Monitoring: The home page of the APC Remote Monitoring Service.

To reconfigure a link, click on that link in the Display column, and change any of the following:

•  Display: The short link name displayed on each interface page.
•  Name: A name that fully identifies the target or purpose of the link.
•  Address: Any URL — for example the URL of another device and server.

For more information on Modbus, see the Modbus Standard Library at www.modbus.org.