Hitachi L100 instruction manual Connecting to PLCs and Other Devices, 24V, Circuits, Com

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Connecting to PLCs and Other Devices

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 configura- tion. 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 poten- tiometer 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.

The variety of applications is practically endless, and is beyond the scope of this manual. It will be important 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 in your application if the maximum current or voltage characteristics of a connection point are exceeded.

Operations and Monitoring

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 inputs require a sourcing output from an external device (such as a 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 compo- nents 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.

Other device		L100 Inverter
Input	signal		Output
	return
circuit			circuit
	signal
Output			Input
	return
circuit			circuit

PLC		Inverter
COM	P24	24V
		+ –
	1
	2	Input
	3
		circuits
	4
	5
	6
	L

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.