Intek RheoVac 950A - Manual (Page 43)

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I:\OFFICE\WPMANUAL\RV950A Appendix C revB.doc Feb. 4, 2010
Table C2.1: Modbus Server Global Settings
Address Description Allowed Values Default Format Read Only?
0001 Restart Modbus Server Write ‘1’ to restart 0 16-bit unsigned No
0002 RheoVac Serial Port Set to ‘0’ internally by
RheoVac System 0 16-bit unsigned Yes
0003 Baud Rate 2400,4800,9600,14400,
19200 bps 9600 16-bit unsigned No
0004 Data Bits 7 or 8 8 16-bit unsigned No
0005 Stop Bits 0 = 1 stop bit
1 = 1.5 stop bits
2 – 2 stop bits 2 16-bit unsigned No
0006 Parity 0 = No Parity
1 = Odd Parity
2 = Even Parity
3 = Mark Parity
4 = Space Parity 0 16-bit unsigned No
0007 Modbus Address 1 – 255 1 16-bit unsigned No
0008 Communication Mode 0 = ASCII
1 = RTU 0 16-bit unsigned No
0009 Conversion Mode 0 = Multiplied Integer
1 = Single Float 0 16-bit unsigned No
0010 Number of Probes 1 – 3 1 16-bit unsigned Yes
C.2.3 MODBUS DATA SETTINGS (Multiplied Integer Mode)
The values listed in Table C2.2 are used only when the Modbus server is in “Multiplied Integer” mode
(“0” written to register 09). These register values determine the power of 10 that is used to multiply each
parameter (effectively shifting the decimal point) before it is transmitted as a 16-bit unsigned integer.
Table C2.2: Modbus Data Multiplier Registers
Address Description Allowed
Values
Default Read
Only?
0011 Multiplier power for Actual Volume Flow 0 – 3 16-bit unsigned No
0012 Multiplier power for Total Mass Flow 0 – 3 16-bit unsigned No
0013 Multiplier power for Water Vapor Flow 0 – 3 16-bit unsigned No
0014 Multiplier power for RheoVac Pressure 0 – 3 16-bit unsigned No
0015 Multiplier power for Water Vapor Specific Volume 0 – 3 16-bit unsigned No
0016 Multiplier power for Water Vapor to Air Mass Ratio 0 – 3 16-bit unsigned No
0017 Multiplier power for Relative Saturation 0 – 3 16-bit unsigned No
0018 Multiplied power for Water Vapor Partial Pressure 0 – 3 16-bit unsigned No
0019 Multiplier power for Air Flow In-Leak 0 – 3 16-bit unsigned No
0020 Multiplier power for Probe Temperature 0 – 3 16-bit unsigned No
C.2.4 MODBUS DATA REGISTERS (Multiplied Integer Mode)
When in Multiplied Integer mode, the RheoVac 950 data values are multiplied by a power of ten specified
in the registers listed in Table C2.2. The resulting values are then transmitted as 16-bit unsigned
integers. Each value therefore needs only 1 register (2 bytes) of allocated space. In this mode, the data
registers are allocated in pairs, with each data value followed by the multiplication power corresponding
to it. For example, assuming all multiplier registers are set to 3, the RheoVac Pressure is transmitted as
follows:
RheoVac Pressure (probe reading) = 1.257
Register 117 (RheoVac Pressure) = 1257
Register 118 (Multiplier Value) = 3