iControlr PROFIBUSr, PROFINETr, DeviceNett, and EtherNet/IPt Generation 4 Slot 9 Gateway
22
Part 1605930−02
E 2020 Nordson Corporation
Flow % Adjust Message
Using Module 5
This module relates to the PLC commands that adjust all the flow nodes to
operate at some percentage of their setpoint. Separate Flow and Atomizing
percentages may be entered.
The percentage value may be from −100% to +100%.
S 0% − Control flow rate at current set point
S −100% − Sets flow rate to zero
S +100% − Doubles the flow rate (limited by saturation)
S negative percent values are expressed in two’s complement form.
Use Address Offset 27 for WAIT function, if needed for the Multi Scan
Method.
Address Offset 28 contains the % value for the Flow setpoint.
Address Offset #29 contains the % value for the Atomize setpoint.
NOTE: A zero in Address Offset 27 does not indicate that this % Adjust
feature is OFF. To turn the feature OFF, or to be sure that the % Adjust is
0% for both Flow and Atomize, it is important to write zeros in Address
Offsets 28 and 29. Once it is certain that % Adjust is OFF (i.e. all
percentages equal to 0), it is permissible to write a zero into Address Offset
27. If this feature is never used it requires no maintenance. However, if it is
(or was) ever used then it is recommended to set Module 5 during system
initialization to a known value. This step is important since the flow control
nodes store their last %Adjust values in EEPROM. When flow control node
power is cycled, they will start up with the last %Adjust value sent to them.
The Gateway sends a broadcast message to each channel of each flow
control node every time the PLC sends a Flow % Adjust message.
Reading Data at the PLC − Input Image Table
Since the data contained in the slave’s Input Image Table is written by the
DSP controller; the data is automatically sent and projected into the PLC’s
master fieldbus memory space. Therefore, for the PLC to read data it is a
simple matter of knowing what data is available at the various addresses of
the PLC’s input image table. This section defines the contents of IO
Modules in the Input Image Table and how it is to be interpreted. Almost all
the data stored in the Input Image Table come from the messages collected
by the gateway from the gun control nodes. Data from the gun control
nodes arrive unsolicited to the gateway by way of the Data Table #4 and
Data Table #7 messages. The Gateway stores all of the gun data locally in
its own memory space and places only a portion of it (as requested by the
PLC) into the dual port memory. The reason the Gateway places only a
portion of all the data into the dual port memory is because the PLC master
cannot accept more than a total of 244 bytes of input data; the total amount
of gun data can require much more than this amount of memory.
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