Galvanic Applied Sciences 943-TGS-CE, Operation Manual

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Revision 5 98 August 2021
Figure 65: Enron Modbus Format
The Enron Modbus format contains 4 nodes on the Modbus tree: Coils , Short Integers,
Long Integers, and Floating Point . Coils are Boolean (i.e. ON or OFF) data points
which have a value of either 0 or 1. Thus, points placed into the Coils should be points
that have only an ON or an OFF state, such as Relay Status points, Fault Status points,
or Warning Status points. Control Command points can also be placed into the Coils
node for remote initiation of different commands. Short Integers are 16-bit whole
numbers with either a positive or a negative sign. Long Integers are 32-bit whole
numbers with either a positive or a negative sign.
Floating Point
values are also 32-bit
numbers, but unlike the integers they do not have a sign, but they do have decimal points.
Because the Floating Point node can display data that includes decimal points, it is the
most suitable node to use for the output of concentration data and other calculated
results.
5.3.2.2 Modicon 16 Format
If Modicon 16 is chosen as the Modbus format , the Modbus list will contain 4 nodes as
shown in Figure 66.
Figure 66: Modicon 16 Format
The Modicon 16 Modbus format contains 4 nodes on the Modbus tree: Output “Coils”
Status, Input Status, Input Register, and Output “Holding” Register . The Input
Status and Output “Coils” Status nodes contain Boolean data points. Data points in
the Input Status node can be written to, so if any Control Command points are required,
they should be placed into the Input Status node. Data points in the Output “Coils”
Status node are read-only, so points placed into this node should include any data points
from the
Relay Status
,
Fault Status
, or
Warning Status
nodes, as data points in these
nodes are all read-only. Output “Holding” Registers are data points that are read-only
outputs of analyzer data, such as concentration values and calculated values like Air
Demand. The Input Register node is used for non-Boolean (i.e. numerical) data points
that can be written to.
The Modicon 16 format only outputs numerical data as 16-bit numbers. Thus,
the ouptut of decimal point data in this format is not possible – all numerical
data output in Modicon 16 is whole number only.