Hitachi NJI-350B manual Analogue Input, Analogue Output

Chapter 8 High-speed counter, PWM / Pulse train output and Analogue I/O

8.9 Analogue Input

The 23-point type CPU is equipped with two points of analogue input. The input to these two points can be set to voltage input or current input individually. The setting of current or voltage input is made in the special internal output WRF06E. This special internal output is stored in the FLASH memory by turning on various setting write requests (R7F6). Once it is stored in the memory, it is not necessary to set the value again when the power is turned on for the next time.

Bit:

WRF06E:

Initial value:

15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
a	b							Not used

0 0

Figure 8.42 Special internal output for selecting the analogue type

WRF06E

Setting value

	Function
Analogue CH0 (Bit a)		Analogue CH1 (Bit b)

C000H	Current input	Current input
8000H	Current input	Voltage input
4000H	Voltage input	Current input
0000H	Voltage input	Voltage input

Please note that the external wiring is different for voltage input and current input. See the section regarding analogue system wiring for the details.

Through the above-mentioned settings, the input data of channel 0 is stored in WX 30 and the input data of channel 1 is stored in WX31. The correspondence between analogue data and digital data is shown in the figure 8.40 (divide 0 to 10 V and 0 to 20 mA in 0 to 4000). The voltage data is converted to 0.0025 [V] per 1H and the current data is converted to 0.005 [mA] per 1H. Therefore, the value ranges that can be measured from the output channel are 0 to 10.2375 [V] for voltage data and 0 to 20.475 [mA] for current data, respectively.

FA0H

(4000)

7D0H

(2000)

FA0H (4000)

7D0H

(2000)

V mA

0 5 10 0 10 20

Figure 8.43 Correspondence diagrams of digital and analogue input

(Example)

If analogue input channel 0 is set to voltage input and the analogue input channel 1 is set to current input, and 3V and 14mA are applied respectively, 4B0H (1200) is stored in WX30 and AF0H (2800) is stored in WX31.

8.10 Analogue Output

The 23-point type CPU is equipped with one point of analogue output. In analogue output, digital values set at WY40 are converted to analogue output, and then output. Switching between voltage output/current output is performed by external wiring; analogue voltage outputs are output when connected to a voltage output terminal, and analogue current output when connected to a current output terminal.

The correspondence between analogue data and digital data is shown in the figure 8.41 (divide 0 to 10 V and 0 to 20 mA in 0 to 4000). The voltage data is converted to 0.0025 [V] per 1H and the current data is converted to 0.005 [mA] per 1H. Therefore, the values that can be output from the output channel are 0 to 10.2375 [V] for voltage data and 0 to 20.475 [mA] for current data, respectively.

V	10			mA 20
	5			10
	0	7D0H	FA0H	0	7D0H	FA0H
		(2000)	(4000)		(2000)	(4000)

Figure 8.44 Correspondence diagrams of digital and analogue output

(Example)

If 5F0H (1520) is set in WY40, 3.8 V is output from the analogue voltage output terminal. When reconnected to the analogue current output terminal, 7.6 mA is output. Please note that if connected to both terminals by mistake, the correct output value will not be output.

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