Hitachi hitachi series inverter 用户手册

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19 
Connecting to PLCs and Other Devices 
Hitachi inverters (drives) are useful in many types of applications. During installation, the 
inverter keypad (or other programming device) will facilitate the initial configuration. After 
installation, the inverter will generally receive its control commands through the control 
logic connector or serial interface from another controlling device. In a simple application 
such as single-conveyor speed control, a Run/Stop switch and potentiometer will give the 
operator all the required control. In a sophisticated application, you may have a 
programmable logic controller (PLC) as the system controller, with several connections to 
the inverter. 
It is not possible to cover all the possible types of application in this manual. It will be 
necessary for you to know the electrical characteristics of the devices you want to connect 
to the inverter. Then, this section and the following sections on I/O terminal functions can 
help you quickly and safely connect those devices to the inverter. 
 
CAUTION: It is possible to damage the inverter or other devices if your application 
exceeds the maximum current or voltage characteristics of a connection point. 
The connections between the inverter and 
other devices rely on the electrical input/output 
characteristics at both ends of each connection, 
shown in the diagram to the right. The 
inverter’s configurable inputs accept either a 
sourcing or sinking output from an external 
device (such as PLC). This chapter shows the 
inverter’s internal electrical component(s) at 
each I/O terminal. In some cases, you will 
need to insert a power source in the interface 
wiring. 
In order to avoid equipment damage and get 
your application running smoothly, we 
recommend drawing a schematic of each 
connection between the inverter and the other 
device. Include the internal components of 
each device in the schematic, so that it makes 
a complete circuit loop. 
After making the schematic, then: 
1.  Verify that the current and voltage for each 
connection is within the operating limits of 
each device. 
2.  Make sure that the logic sense (active high or active low) of any ON/OFF connection is 
correct. 
3.  Check the zero and span (curve end points) for analog connections, and be sure the 
scale factor from input to output is correct. 
4.  Understand what will happen at the system level if any particular device suddenly 
loses power, or powers up after other devices. 
Other device
Input 
circuit
Output 
circuit
WJ200 inverter 
Input 
circuit 
Output 
circuit 
signal 
return 
signal 
return 
Other device 
WJ200 inverter 
Input 
circuits 
P24 
24V 
+ - 
GND
…