APPENDIX A:
Modbus map for legacy flare.IQ Gen 1 installations
flare.IQ Gen 2 is designed to be backward compatible
with Gen 1 installations for flare control applications
(digital meter verification feature is not available in
Gen 1). For those customers that wish to continue to use
their existing DCS configuration for flare control, the
Gen 2 system supports the Modbus map of unsigned
integers shown in table 11 (analog inputs) and
table 12 (analog outputs). Since all analog values sent
and received must be integers, these values have to be
scaled appropriately as described in section A.1 to maintain
the desired range and accuracy. The “scaling” column
in the table below shows the scaling factor to multiple
or divide a value by before sending or after receiving
(/ = divide, * = multiply) on DCS master.
Table 11: Modbus address list for flare.IQ Gen 1 legacy customers (analog inputs for flare control)
Register tag name
Register
address
Number of
registers
Description
Scaling
factor
AR
10
1
Argon concentration, fraction (0.0 to 1.0)
*10
CO2
11
1
Carbon dioxide concentration, fraction (0.0 to 1.0)
*10
CO
12
1
Carbon monoxide concentration, fraction (0.0 to 1.0)
*10
H2
13
1
Hydrogen concentration, fraction (0.0 to 1.0)
*10
N2
14
1
Nitrogen concentration, fraction (0.0 to 1.0)
*10
O2
15
1
Oxygen concentration, fraction (0.0 to 1.0)
*10
H2O
16
1
Water vapor concentration, fraction (0.0 to 1.0)
*10
MW_INPUT
20
1
Molecular weight from GC/MS, g/mol
*100
NHVVG_INPUT
21
1
Net heating value of vent (flare) gas, BTU/SCF
*10
QFUEL_TC
30
1
Fuel gas flow rate, SCFH
/10
QFLARE_TC
40
1
Flare flow rate, SCFH
/100
TFLARE_TC
41
1
Flare temperature, degrees Fahrenheit
*10
PFLARE_TC
42
1
Flare pressure, PSIa
*100
CFLARE_TC
43
1
Flare sound speed, ft/s
*10
QSTEAM_TC
50
1
Steam flow rate, PPH
/10
TSTEAM_TC
51
1
Steam temperature, degrees Fahrenheit (future use)
*10
PSTEAM_TC
52
1
Steam pressure, PSIg (future use)
*100
QAIR_TC
60
1
Air flow rate, CFM
/10
TAIR_TC
61
1
Assist air temperature, degrees Fahrenheit
*10
43
Summary of Contents for flare.IQ Generation 2
Page 1: ...flare IQ Generation 2 Operation and maintenance manual...
Page 2: ...2...
Page 3: ...flare IQ Generation 2 Operation and maintenance manual 910 350 rev A June 2020 3...
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Page 38: ...Figure 30 System wiring diagram 38...
Page 48: ...48...