PN 305200901, Rev YT
Holding Registers
Since the RAM space on the analyzers is limited and not every customer’s
DCS\SCADA\DAS\PLC supports Modbus oating point value transfer, oating
point values that are commonly accessed on a 3050 Analyzer are scaled and
converted into integer values to load into Modbus registers for transmission.
The Register values need to be scaled back at the receiving end to yield the
actual values. The size of a Modbus holding register is 16-bit which can assume
a value from -32768 to +32767 in two’s complement. The holding Register
Denitions, Units of measurement, and Scaling factors are shown below. Ac-
cess is ‘r’ (read) or ‘w’ (write).
REG DEFINITION
UNITS SCALING
ACCESS
0
Current moisture concentration (Moisture= 51 Hex)
ppm 100
r
1
Concentration held during verication (HeldConc= 52 Hex)
units 100
r
2
Sensor frequency (Frequency= 53 Hex)
Hz
1 r
3
Delta frequency (DeltaFrequency= 54 Hex)
Hz 100
r
4
Flow reading (Flow= 55 Hex)
sccm 100
r
5
Sensor pressure (Pressure1= 4B Hex)
kPa 100
r
6 Electronics temperature (EETemp= 4C Hex)
°C 100
r
7 Sensor temperature (CellTemp= 4d Hex)
°C 100
r
8
System alarms and warnings (SystemState= 5F Hex) — 1 r
9
Flow control output (Loop1Duty= 60 Hex) —
100
r
10
Heater control output (Loop2Duty= 61 Hex) —
100
r
11
Reading is ready (DataState= 62 Hex) — 1 r
12
Sensor pressure analog input (Analog0= 64 Hex)
counts
1 r
13
Flow analog input (Analog1= 65 Hex)
counts
1 r
14
Sensor temperature analog input (Analog2= 66 Hex)
counts
1 r
15
Process pressure analog input (Analog3= 67 Hex)
counts
1 r
16
Analyzer cycle status (OutputState= 68 Hex) — 1 r
17
Reference period counter (ReferencePer= 69 Hex)
second
1 r
18
Sample period counter (SamplePer= 6A Hex)
second
1 r
19
Wet sensor frequency reading (WetFreq= 6B Hex)
Hz
1 r
20
Dry sensor frequency reading (DryFreq= 6C Hex)
Hz
1 r
21
Verication counter (CalcCycleCount= 6F Hex)
minute
1 r
22
Electronics temperature input (AnalogEE= 70 Hex)
counts
1 r
23
Current ow reading (CurrentFlow= 8A Hex)
sccm 100
r
24
Maximum ow deviation (MaxFlowDev= 8E Hex
sccm 100
r
25
Special command (MODBUSCommand= 93 Hex) — 1
r,w
26
Sensor pressure coecient (Pressure1Span= 2 Hex)
kPa 100 r,w
27
Sensor pressure oset (Pressure1Oset= 3 Hex)
kPa 100 r,w
Serial Communication Interface | 6-5