3 SPECIFICATIONS

3.2 Function List

Table 3.2 shows the function list of the A/D converter modules.

MELSEC-Q

Table 3.2 Function list

Item

 

Function

Reference section

A/D conversion enable/

(1)

Specifies whether to enable or disable the A/D conversion for each channel.

Section 3.4.2

disable setting

(2)

By disabling the conversion for the channels that are not used, the

 

sampling time can be shortened.

 

 

 

 

 

(1)

Sampling processing

 

 

 

The A/D conversion for analog input values is performed successively for

 

A/D conversion method

 

each channel, and the digital output value is output upon each conversion.

Section 3.2.1

(2) Averaging processing

 

 

For each channel, A/D conversion values are averaged for the set number of

 

 

 

times or set amount of time, and the average value is output as a digital value.

 

Maximum and minimum

(1) The maximum and minimum values of the digital output values is retained

Section 3.2.2

values hold function

 

in the module.

 

 

 

(1)

Errors arising from changes in the ambient temperature of the module are

 

Temperature drift

 

automatically compensated for to improve conversion accuracy.

——

compensation function

(2)

The temperature drift compensation function can be performed at (A/D

 

 

 

conversion time for all channels) + 160 s.

 

 

(1)

The resolution mode can be switched according to the application, and digital-

 

 

 

value resolution settings of 1/4000, 1/12000 or 1/16000 can be selected.

Section 3.1.1

Resolution mode

(2)

The resolution mode setting is applicable to all channels.

Section 4.5

 

(3)

See Section 3.1.1 for the digital output values and maximum resolution in

 

 

 

 

normal resolution mode and high resolution mode.

 

Online module change

(1) A module change is made without the system being stopped.

Chapter 7

3.2.1 A/D conversion methods

There are two A/D conversion methods, sampling processing and averaging processing.

(1) Sampling processing

A/D conversion is performed successively for the analog input value, and the converted digital output values are stored in the buffer memory.

The sampling processing time depends on the number of channels used (the number of channels set to A/D conversion enable) and whether the temperature drift compensation function is available.

(a)Without the temperature drift compensation function

(Processing time) = (Number of channels used) 80 ( s/1 channel)

(b)With the temperature drift compensation function

(Processing time) = (Number of channels used) 80 ( s/1 channel) + 160 s [Example]

When three channels (channels 1, 2 and 4) are A/D conversion enabled with the temperature drift compensation function, the sampling processing time is 400 s.

3 80 + 160 = 400 ( s)

(2)Averaging processing

For channels for which averaging processing is specified, A/D conversion is performed for the set number of times or the set amount of time. The average value is calculated from the sum of values excluding the maximum and minimum values, and then stored in the buffer memory.

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Mitsubishi Electronics Q68ADI, Q68ADV Function List, 1 A/D conversion methods, Sampling processing, Averaging processing
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Q68ADV, Q68ADI, Q64AD specifications

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