Rockwell Automation 1758-RTU202 DataSite Software User Manual FRN 1.2 - Manual (Page 329)

Publication 1758-UM002D-EN-P - October 2010
Enron Modbus Protocol for the 1758-FLO DataSite Controller 329
Long Integer Variables
Long integer variables are accessed using commands 3, 6, and 16. These
commands are similar to the corresponding standard Modbus commands, and
they use Enron Modbus addressing. The size of the data fields for each
variable is determined by the variable address. The read command returns four
bytes for each requested register. The write command provides four bytes for
each register value. Read-only (RO) registers cannot be written by using
commands 6 and 16.
The following table lists all the long integer variables used by Enron Modbus
in the DataSite controller.
Meter Run 0 Data Variables
Floating Point Variables
Floating point variables are accessed using commands 3, 6, and 16. These
commands are similar to the corresponding standard Modbus commands, and
they use Enron Modbus addressing. The size of the data fields for each
variable is determined by the variable address. The read command returns four
bytes for each requested register. The write command provides four bytes for
each register value. Read-only (RO) registers cannot be written by using
commands 6 and 16.
Accumulated flow variables
Register Description Access
5001 Total accumulated run time. Unit is seconds. RO
5002 Total flow time of the previous day. Unit is seconds. RO
5003 Total flow time of the current day. Unit is seconds. RO
5004 Total flow time of the previous hour. Unit is seconds. RO
5005 Total flow time of the current hour. Unit is seconds. RO
5006 Total accumulated mass flow quantity. RO
5007 Total accumulated flow volume at base conditions. RO
5008 Total accumulated flow volume at flowing conditions. RO
5009…5010 Reserved —