11
Set up
ModBus
in MACH:
“Setting goals is the first step in turning the invisible into the visible.” - Tony Robbins
First, it is helpful to understand what ‘ModBus’ is and also what it is not.
It is not something extra that you have to buy and install on your computer.
‘ModBus’ refers to an interface standard just like ‘
serial’
, ‘
parallel’
, ‘
USB’
, ‘
Ethernet’
, etc.
The physical connection varies, and in this case, the connection is made using any
normal USB port on your computer.
However, ‘ModBus’ is not a physical thing. It is a set of rules. When two devices follow
the same rules, they can communicate and send information back and forth.
The speed and capacity
of a ‘ModBus’ setup depends on what kind of hardware it is
running on and what kind of ‘topology’ (serial, Ethernet, etc.) is being used.
Second, you just need to know the steps to take to set up your ModBus.
ModBus notes:
MACH3 ModBus starts automatically when MACH3 starts and it talks to the controller thru
COM
xx.
While xx can be any number, it must be the SAME for both the controller and ModBus, and that will
only happen if the correct sequence is followed in the startup.
In the explanation below, COM8 is used as an example for clarity, but remember that your number
may be different.
It is important to recognize that these are not actual physical ports, but are ‘virtual’
ports created on-the-fly and reside in the comput
er’s memory ‘emulating’ a real port.
IMPORTANT: While plugged into the USB port, the controller will automatically create the
NEXT AVAILABLE COMxx in the computer EACH time it is powered on, so the COM number
that is created depends on the conditions AT THE TIME the controller is powered on.
In this example, COM8 is the next available so the Controller creates COM8. There is no physical
COM8, but the ‘fake’ COM8 behaves as if it was real.
In the configuration, MACH was told to use COM8 for ModBus communication, so if MACH3 is
started BEFORE the controller, it will still open
‘COM8’ even though there is no controller present.
If the controller is started AFTER MACH is already running, when the controller scans for the next
available COMxx it will find
COM8 is already ‘IN USE’ and will, therefore, skip past it and will create
COM9. If this happens, MACH and the Controller will be on different ports, so . . no talkie.
