DuoPro 1000 Interface module

The DuoPro is a powerful low cost interface between an American Automatrix building automation control system and a Carrier chiller control system.

The DuoPro acts as a slave (non-peer) on the American Automatrix Public Unitary Protocol (RS485 or PUP) network. It serves as a bridge to the Carrier Dataport, accepting data for up to 64 variables on each of 3 devices through a serial (RS232) port. It processes strings of ASCII characters supplied by the Dataport and provides them on request to the PUP as attributes with values and descriptions. The communication speed (baud rate) is independently programmable for each port in increments of 1200 baud up to 19.2K baud.

To provide maximum flexibility within the Automatrix system, the DuoPro does minimal processing of data acquired from the Dataport. All data is presented to Automatrix as an attribute with a text description. The text description is supplied by the Dataport, with Variable Name, Engineering Units, and Description in the text string. In order to provide data typing and alarm interpretation, each variable provided by the Dataport for chiller monitoring (51 variables) is processed to define its value and data type as appropriate for the PUP network. Additionally, each data value supplied to the Automatrix system will have a corresponding attribute representing the "status" of that data point as supplied by the Carrier Dataport.

The DuoPro responds to "Read Attribute" requests on the PUP network with "Numeric Data Response" as defined by the Public Unitary Protocol Guidelines, Version 8, dated December, 1992, by American Automatrix. The DuoPro is configured by sending it "Write Attribute" commands.

The DuoPro will respond to all alarm requests with "normal."

The DuoPro maintains a table of the most recent variables received from the chiller. A configuration attribute is provided to determine how old the table must be before a read request from the PUP causes a new read request to be sent to the Dataport. If the Dataport does not respond, all values are returned as zeros.

A configuration attribute is available to request the most recent data provided by each chiller, along with time since its acquisition, irrespective of its age. This allows post-mortem analysis of chillers.

Configuration parameters are maintained in EEPROM and all data tables are maintained in battery backed up SRAM. This allows the DuoPro to survive power outages with no loss of data.

Digital Action Corporation
1545 N. Larrabee St, Ste 3-South
Chicago, IL 60610
Voice: 312.266.4931
Fax: 312.337.0366
daction@mcs.com