How to collect digital and analog quantities in industrial automation control?

In industrial automation control, we often encounter various concepts such as switching quantity, digital quantity, analog quantity, and pulse quantity. How do you understand these concepts and how to collect them? This article will analyze with you.

I. Overview

1, digital quantity

Many people confuse the amount of digital with the switch and confuse it with the analog. The digital quantity is a discrete physical quantity in time and quantity, and the signal represented by it is a digital signal. The digital quantity is a signal composed of 0 and 1, which is coded to form a regular signal, and the quantized analog quantity is a digital quantity.

Figure 1 Digital signal

2, analog quantity

The concept of analog corresponds to the amount of digital, but after quantization, it can be converted into digital. The analog quantity is a continuous physical quantity in both time and quantity, and the signal represented by it is an analog signal. Any value of the analog quantity in a continuous change process is a specific meaningful physical quantity, such as temperature, voltage, current, and the like.

Figure 2 analog signal

3, the amount of switching

Generally refers to the "on" and "off" states of the contacts. Generally, in the computer equipment, "0" or "1" is also used to indicate the state of the switch. The switching quantity is divided into an active switching quantity signal and a passive switching quantity signal. The active switching quantity signal refers to the state of “on” and “off” being a signal with a power supply, and the professional name is a step signal, which can be understood as The pulse quantity generally has signals of 220VAC, 110VAC, 24VDC, 12VDC, etc. The passive switch signal refers to the signal without power supply when it is in the "on" and "off" states, and is generally called the dry contact. The resistance test method is resistance 0 or infinity.

Figure 3 Switching

4, the amount of pulse

The amount of pulse is the amount of semaphore whose instantaneous voltage or current changes from one value to another. After quantization, the change continues to be a regular quantity, and if it changes from 0 to a fixed value and remains unchanged, it is the amount of switching.

Figure 4 pulse signal

Second, how to collect digital and analog

ZLG Zhiyuan Electronics DM100, DP100 data acquisition recorder is a general-purpose data acquisition device. It provides users with diverse data acquisition modules through modular design framework, and comprehensively collects DC voltage, DC current, digital quantity, temperature and humidity. A variety of sensor signal data, real-time operation and display a variety of measurement results. The user can perform custom operation processing on the collected data and realize high reliability data storage and recording function.

Figure 5 DM100 data acquisition recorder

At the same time, it adopts intelligent architecture design, which consists of DM100 host, DM90PS power module and high-precision data acquisition module. A single DM100 host can connect 1-10 data acquisition modules, and multiple cascades can be expanded to up to 200 acquisition channels. Strong scalability, suitable for multi-channel data acquisition and recording.

Figure 6 DM signal measurement

The DM100 data acquisition recorder, from data acquisition, measurement operations to storage records, takes advantage of the overall optimal performance of the data acquisition recorder.

Figure 7 DM100 performance advantages