Owner manual

-C7-

I:\OFFICE\WPMANUAL\RV950A Appendix C revB.doc Feb. 4, 2010

To allow for future expansion and up to three different probes, each probe is allocated a space of 100

registers, with the registers for the first probe beginning at address 0101. Registers for the second probe

begin at address 0201, and the third probe begins at register address 0301. Table C2.3 details the

RheoVac Model 950 data register setup when in Multiplier Integer mode.

Table C2.3: Modbus Data Registers (Multiplied Integer Mode)

Address Description Format Read Only?

0101 – 0105 Probe Serial Number 10 ASCII characters Yes

0106 Error Code: see Section C.2.6 16-bit unsigned Yes

0111 Actual Volume Flow 16-bit unsigned Yes

0112 Multiplier Value 16-bit unsigned Yes

0113 Total Mass Flow 16-bit unsigned Yes

0114 Multiplier Value 16-bit unsigned Yes

0115 Water Vapor Flow 16-bit unsigned Yes

0116 Multiplier Value 16-bit unsigned Yes

0117 RheoVac Pressure 16-bit unsigned Yes

0118 Multiplier Value 16-bit unsigned Yes

0119 Water Vapor Specific Volume 16-bit unsigned Yes

0120 Multiplier Value 16-bit unsigned Yes

0121 Water Vapor to Air Mass Ratio 16-bit unsigned Yes

0122 Multiplier Value 16-bit unsigned Yes

0123 Relative Saturation 16-bit unsigned Yes

0124 Multiplier Value 16-bit unsigned Yes

0125 Water Vapor Partial Pressure 16-bit unsigned Yes

0126 Multiplier Value 16-bit unsigned Yes

0127 Air Flow In-Leak 16-bit unsigned Yes

0128 Multiplier Value 16-bit unsigned Yes

0129 Probe Temperature 16-bit unsigned Yes

0130 Multiplier Value 16-bit unsigned Yes

C.2.5 MODBUS DATA REGISTERS (Single Float Mode)

In Single Float mode, all of the data values are converted into the 4-byte, big-endian hexadecimal string

corresponding to their single-precision float representation. The Modbus client program must be capable

of converting these 4-byte values back into single-precision float values. If the client software is unable

to make this conversion, the Multiplied Integer mode must be used. Data in the Single Float mode is

transmitted as follows:

RheoVac Pressure (probe reading) = 1.257

Single-Float Hex Representation = 0x3FA0E560

As in the Multiplied Integer mode, each probe is allocated a space of 100 registers, with the registers for

the first probe beginning at address 0101. Registers for the second probe begin at address 0201, and the

third probe begins at register address 0301. Table C2.4 details the RheoVac Model 950 data register

setup when in Single Float mode.