A.1. Scaling Modbus data (for legacy Gen 1 systems only)
All analog data is transferred to/from the flare.IQ as 16-bit, unsigned integers. Each input parameter and output value occupy
a single 16-bit Modbus register. To maintain the desired dynamic range or turndown, data may be scaled by multiplying or
dividing by a multiple of ten.
Example 1:
XH2_INPUT is a value written to the flare.IQ containing the
percentage of hydrogen in the flare gas, expressed in the
Modbus address list as:
Cmd:
address
Signal
name
Description
Cfg Scaling Units
X:0013
XH2_INPUT
Hydrogen
content
(from GC/MS)
*10
%
The GC/MS data indicates that the H2 content is 27.5%.
Applying the scaling factor (*10): 27.5 * 10 = 275
275 is the integer value that should be written to Modbus
register 0013 with command 06 (preset single register).
Example 2:
QFUEL_DEMAND is a value read from the flare.IQ containing
the amount of supplemental fuel in standard cubic feet per
hour (SCFH) required for compliance. It is expressed in the
Modbus address list as:
Cmd:
address
Signal
name
Description
Cfg Scaling Units
4:0001
QFUEL_
DEMAND
Fuel Gas
Demand
*10
SCFH
Reading Modbus register 0001 with command 04
(read input register) returns the integer value 3125.
Applying the scaling factor (*10): 3125 * 10 = 31,250
31,250 SCFH is the amount of supplemental fuel required
for compliance.
Example 3:
VTIP_ACTUAL is a value read from the flare.IQ containing
the velocity of the flare gas through the flare tip in feet per
second (ft/s). It is expressed in the Modbus address list as:
Cmd:
address
Signal
name
Description
Cfg Scaling Units
4:0004 VTIP_
ACTUAL
Flare tip
velocity
calculated
/100
ft/s
Reading Modbus register 0004 with command 04
(read input register) returns the integer value 4833.
Applying the scaling factor (/100): 4833/100 = 48.33
48.33 ft/s is the calculated flare gas velocity.
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Summary of Contents for flare.IQ Generation 2
Page 1: ...flare IQ Generation 2 Operation and maintenance manual...
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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...
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