Hitachi hitachi series inverter user manual Connecting to PLCs and Other Devices, Gnd

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 device	signal	WJ200 inverter
other devices rely on the electrical input/output					Input		Output
characteristics at both ends of each connection,						return
					circuit		circuit
shown in the diagram to the right. The
						signal
inverter’s configurable inputs accept either a					Output		Input
sourcing or sinking output from an external					circuit	return	circuit
device (such as PLC). This chapter shows the
inverter’s internal electrical component(s) at
each	I/O terminal. In some		cases, you	will	Other device		WJ200 inverter
need to insert a power source in the interface
wiring.						P24	+ - 24V
In order to avoid equipment damage and get
your	application	running	smoothly,	we		1
recommend drawing a schematic of each
connection between the inverter and the other						2
device. Include the internal components of							Input
each device in the schematic, so that it makes					…	3	circuits
a complete circuit loop.
						…
After making the schematic, then:
1. Verify that the current and voltage for each						7
connection is within the operating limits of					GND	L
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.

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