16. Add-on Modbus RTU
66
Dr. A. Kuntze
I
Gutes Wasser mit System
Robert-Bosch-Str. 7a
40668 Meerbusch
+49 (0) 2150-7066-0 / Fax -60
www.kuntze.com
16.3. Registers
Neon
®
provides the following variables:
˃
Measured values: measuring parameter, temperature, and raw value
˃
Controller outputs: S1 and S2 for add-on controller and S1 for add-on volume based dosing
˃
Status of digital inputs and outputs: digital inputs 1 and 2, relays 1-3
˃
Event messages
˃
Calibration results as in the Cal/Info menu
˃
Instrument data incl. activated add-ons
All parameter settings can be read and most parameters can be set via the interface.
All test functions can be activated via the interface.
16.3.1. How to read variables
Each variable has at least three registers. The first register contains the value, the second in the lower
8 bit the number of decimal places and in Bit 8 the percentage flag, which is set if a value is expressed
as percentage of a given range. In that case, the value of the first register lies within 0 (0%) and 10000
(100%). The third register conatins a code indicating a unit or text – refer to table “units and texts”.
Numerical values with a limited range have two additional registers specifying the minimum and
maximum value of the range.
Example for a numerical value without percentage flag:
The temperature is listed as follows:
1. register: 4160, quantity of registers: 5
If you read these five registers, the response is as follows:
Reg. 1 (4136)
Reg. 2 (4137)
Reg. 3 (4138)
Reg. 4 (4139)
Reg. 5 (4140)
250d
1d
1001d
-300d
1400d
Value
Number of
decimal places
Code of unit
(°C)
Minimum of
range
Maximum of
range
The 1 in the second register means:
˃
Value and range limits have to be divided by 10 to achieve one decimal place.
˃
The percentage flag is not set. Otherwise the number in the second register would be 257 (=256+1;
expressed as hexadecimal value 0101h). The value is not a percentage of the range but already
the true measured value.
The first register gives the value 250. This represents a temperature of 25.0 and from the third register
the unit °C.
