Hello everyone !
Today we are going to drive asynchronous motor with Omron MX2 Frequency Inverter.
Although MX2 has contain wide-range functionality , today we have just focus on intelligent inputs and internal output.
First move on with control logic signal specifications. These terminals can be seen obviously from pictures that i shared below.
We are going to focus on logic input and relay contacts parts which have marked with red circles on the picture 2.
Terminals , , , , ,  and  are identical, programmable inputs for general use.
The input circuits can use the inverter’s internal (isolated) +24 V field supply or an external power supply.
I will describe input circuits operation and how to connect them properly to switches or transistor outputs on field devices.
The MX2 inverter features selectable sinking or sourcing inputs. These terms refer to the connection to the external switching device-it either sinks current (from the input to GND) or sources current (from a power source) into the input. PNP and NPN can be referred SOURCE and SINK respectively.
Let’s discover these wiring types with pictures !
The two diagrams at the right input wiring circuits using the inverter’s internal+24 V supply.
Each diagram shows the connection for simple switches, or for a field device with transistor outputs.
Note that in the lower diagram, it is necessary to connect terminal [L] only when using the field device with transistors.
Be sure to use the correct connection of the short bar shown for each wiring diagram.
The two diagrams at the right show input wiring circuits using an external supply.
If using the “Sinking Inputs, External Supply” in below wiring diagram, be sure to remove the short bar, and use a diode (*) with the external supply. This will prevent a power supply contention in case the short bar is accidentally placed in the incorrect position.
For the “Sourcing Inputs, External Supply”, please connect the short bar as drawn in the diagram below.
It can be seen clearly user must be careful whether short bar should be added or not.
We will use internal supply which is source (PNP) type in our applications.
That’s why we must make short circuit between PLC and L terminals and these connection can be seen from Picture 3.
Intelligent function summary table which has contain Symbol , Code , Page number in User manuel and Name related with ınput functions can be seen from Picture 4.
In our application we will applicate just Forward Run/Stop , Reverse Run/Stop.
Let’s start with Forward and Reverse Run/Stop functions.
In order to do these applications we have to set parameters of terminals C001 and C002 which are belong to terminal  and  respectively and A002 parameter must be change to 1 which means Run Command Selection takes reference as Control Circuit Terminals.
These operations can be seen from Picture 5.
Now its time to drive asynchronous motor !!!
From Picture 6 it can be seen that when +24V connect with terminal  motor has rotated forward direction. Hovewer when +24V connect with terminal  motor has rotated reverse direction.
If you wonder what happen if terminal  and  connected with +24V at the same time , let me say that , inverter enters the Stop Mode (Yeah i have wondered too 🙂 )
Notice that : Direction of motor that seen from Picture 6 might be seem differences according to your R-S-T connection. Briefly , it is not same all the time.
Let’s look at Internal Relay Output. The MX2 has an internal relay output with normally open and normally closed contacts. The output signal that controls the relay is configurable as “Alarm Signal” and it had configured in default setting. This signal reference can be change with C026 parameter. As I sad before it has configured ‘5’ “Alarm Signal” in default.
C026 parameter function selection choices can be seen below ;
Generally in the industry , this parameter used for alarm signal output.
Therefore , we are going to use this output as an alarm signal.
But let’s first configure th terminal as an External Trip function and then in order to activate internal relay output we trigger th terminal with +24V source.
These all operation as i mentioned above can be seen on Picture 7.
Finally we have finished our applications for today , in the future I want to arrange a document about changing speed of motor with analog reference and multiple speed settings with intelligent input terminals through MX2 inverter.
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