This article is mainly about the introduction of pulses, and focuses on the detailed distinction between the pulses sent by the PLC and the pulses received by the driver.
pulsePulse usually refers to a pulse-like short-term electrical shock (voltage or current) often used in electronic technology. The main characteristics are waveform, amplitude, width and repetition frequency. A pulse is a signal that occurs in a short period of time in the entire signal period relative to a continuous signal, and there is no signal in most of the signal period. It's like a person's pulse. Now generally refers to the digital signal, it has a signal half of the time in a cycle. The signal in the computer is a pulse signal, also called a digital signal. In addition, pulses are also used to express impulses and demands on thoughts and emotions.
Taken literally-the shock wave generated by the beating of the pulse. The definition of pulse is actually this: the waveform of voltage (V) or current (A) is like the pulse wave on the electrocardiogram. But what power pulses, sound pulses...and how to explain it—the original intent of the pulses is extended: mechanical forms such as waves emitted at the same time interval.
The academic definition of pulse is: the change process of a physical quantity that changes suddenly in a short duration and then quickly returns to its initial value is called pulse. From the definition of pulse, it is not difficult to see that the pulse has the characteristic of interval, so we can regard the pulse as a kind of signal. The definition of impulse signal arises from this: In contrast to continuous signals (signals that exist for a short period of time in the entire signal period), there is no signal in most of the impulse signal periods. It's like a person's pulse. Pulse signal generally refers to a digital signal, which has a signal for half of the time (or even longer) in a cycle. The signal in the computer is a pulse signal, also called a digital signal.
Related terms
Nerve impulse
Nerve impulse, correctly speaking, should be called nerve im-pulse (nerve im-pulse). When a certain part of the nerve is stimulated with sufficient intensity, an action potential is generated in that part and propagates in two directions along the nerve fiber from this point. Impulse has the same meaning as action potential, but impulse is used when viewed as a signal propagating along the axon. According to the original location of the impulse, the central nerve is the organ that produces effects from the center to the periphery, and the central nerve conducts unidirectionally from the peripheral receptors to the center. Its role is to connect the central and peripheral signals. Impulse conduction speed can vary depending on the presence or absence of myelin and thickness of nerve fibers. The conduction velocity of myelinated nerves is directly proportional to the fiber diameter. In mammals, it is expressed as fiber diameter (micrometers) × 6 meters per second, and the maximum is 120 meters per second. The conduction velocity of unmyelinated nerves is proportional to the square root of the diameter. Proportional, usually below 2-3 m/s.
Pulse signal
The voltage or current that changes suddenly in an instant and has an extremely short acting time is called a pulse signal. It can be repeated periodically, aperiodic or single. The pulse signal is a discrete signal with various shapes. Compared with ordinary analog signals (such as sine waves), the waveforms are not continuous on the time axis (there is a clear interval between the waveform and the waveform) but have a certain periodicity. Is its characteristic. The most common pulse wave is a rectangular wave (that is, a square wave). The pulse signal can be used to express information, and can also be used as a carrier wave, such as pulse code modulation (PCM), pulse width modulation (PWM), etc. in pulse modulation, and can also be used as a clock signal for various digital circuits and high-performance chips. . The so-called pulse signal expressed in plane coordinates is a curve with countless breakpoints, that is to say, the limit of points does not exist in some periodic places, such as sawtooth waves, and also the signals of digital circuits used in computers, 0, 1. . Pulse signal, that is, signal like pulse beating, compared to direct current, intermittent signal, if you describe it with water flow, direct current means that the faucet is kept on and flowing, and the pulse is the continuous turning on and off of the faucet to form a water pulse. You turn on the flashlight and the light turns on. This is DC. If you keep switching the light on and off, pulses are formed. The switching speed is the pulse frequency.
Electromagnetic Pulse
Electromagnetic pulse (EMP) is a powerful energy field generated instantaneously. It is very sensitive to energy waves and can destroy countless power systems and high-tech microcircuits at a distance. The explosion of nuclear weapons in the high-altitude atmosphere can produce a huge electromagnetic pulse effect, which is the high-altitude electromagnetic pulse (HEMP) phenomenon.
Pulse reactor
A reactor that can reach the supercritical state within a short time interval, thereby generating high pulse power and strong neutron flux, and being able to safely and reliably operate repeatedly for many times. It is divided into thermal neutron pulse reactor and fast neutron pulse reactor. China has built a uranium-hydrogen zirconium pulse reactor, which uses uranium-hydrogen zirconium as fuel. It mainly uses hydrogen as a moderator. When the power increases, the temperature increases, the moderating effect of hydrogen decreases, and the reactivity decreases immediately. The reactor has a large prompt negative temperature coefficient, so it runs in pulses. In addition to training personnel, conducting research, and producing short-lived radioisotopes, pulsed reactors can also be used to treat cancer, neutron photography, activation analysis, and irradiate fuels and materials.
Pulse power
The user's load needs to be powered on intermittently, that is, according to a certain time rule, the load is powered on for a certain period of time, and then the power is turned off for a certain period of time. The on and off form a cycle at a time. Such repeated execution constitutes a pulse power supply. For example, in the sophisticated process of non-polar electrolytic capacitors, it is necessary to charge the capacitor in the forward direction for a period of time, then discharge, and then charge the capacitor in the reverse direction for a period of time, and then discharge, thus forming a forward direction→discharge (power off)→reverse→ Discharge → positive..., and so on.
1. Single pulse power supply
Single-pulse power supplies generally output one-way pulse current with fixed parameters. If you want to change the pulse parameters, you need to reset it after stopping the machine.
2. Double pulse power supply
The dual-pulse power supply generally outputs a periodic commutation pulse current with fixed parameters. If you want to change the pulse parameters, you need to reset after the shutdown. The reverse pulse of the dual-pulse power supply The anodizing and dissolving makes the metal ion concentration on the cathode surface rise rapidly, which is beneficial to the subsequent The cathode cycle uses high pulse current density, so the coating is dense, bright, and low porosity; the reverse pulse anode stripping of the double pulse power supply greatly reduces the entrapment of organic impurities (including brightener) in the coating, so the coating purity is high , Strong resistance to discoloration. YS-9000 wing-up intelligent pulse electroplating power supply provides a powerful means for the development and production of nano electroplating technology
Specifications
1. Output waveform: square wave pulse or DC
2. Pulse frequency: 1-100HZ 100-1000HZ 200-2000HZ 500～5000Hz 10KHZ-30KHZ (optional can be customized)
3. Pulse duty cycle: 0～100%
4. Forward and reverse pulse commutation time: 0～9999ms
5. Output voltage: 0-100V
6. The maximum average output current: 0-5000A
7. Maximum peak current: 15000A
Pulse Width
It is the duration of the high level. It is often used as a sampling signal or trigger signal for components such as thyristors.
Pulse circuit
It is the circuit for generating, shaping and transforming the pulse waveform. The pulse circuit is composed of two parts: an inertia circuit and a switch. The function of the switch is to destroy the steady state and make the circuit appear transient.
Pulse dial
It is a time-domain processing method, which uses the number of pulses to represent the number digits. Pulse dialing has strict requirements on the pulse width, size, spacing, and shape. If these parameters are changed due to line interference or other reasons, it may cause errors in number reception. On the other hand, because each pulse occupies a certain amount of time (generally, each pulse occupies 100ms), which makes this dialing method relatively slow.
Pulse heating
It uses various waveform pulse currents to heat in an intermittent manner to meet some special process requirements.
Pulse wave
It is the signal waveform generated in the form of impact.
Any distinction between the pulse sent by the PLC and the pulse received by the driverThere are generally 3 reasons for deviation
1 Is the coupling fixed? (Although it is simple, it still depends on it)
2 Whether the signal line has an insulating layer, and whether it is connected to the driver in an insulated manner.
3 There are high-voltage wires (220V, 380u) near the signal wires and go separately
When the pulse sent by the PLC is monitored on the servo drive, it is seen that the value is different every time it reaches a position. For example, if two positions move back and forth, two fixed values ​​should change. The PLC is very close to the servo drive. The signal line is about 20cm long. There is also a servo drive next to it. The situation is similar. All use twisted-pair shielded wires, and the quality of the wires is not bad. The signal line is completely separated from the motor line. The equipment is mainly used for two servo positioning. The control cabinet is a three-phase 380 power supply, and there is a three-phase motor for hydraulic use. The single-phase power has a separate neutral wire. Take the three-phase one to connect it for use. Lots of punches. There is no ground wire nearby, and the servo drive is just connected to the control cabinet shell.
PLC and drive pulse signal connection methodIndustrial control products are divided into two groups. The barriers are the same, and there are many incompatible places. This is the European system represented by Germany and the Japanese system represented by Japan.
Most of the Japanese pulse input uses 5VDC differential or pulse + direction. Of course, 24V pulse + direction is the same, just a series of resistors. You have to be optimistic about the manual.
But the pulse feedback output is a bit tragic. Most of them are 5Vdc differential. European PLCs are "immune" to such a low voltage. The Panasonic A4 servo drive pulse output used some time ago is 5VDC differential and has no collector.
Delta is a Japanese faction. It is estimated that some models support 5VDC differential and have not been used yet.
Pay more attention to the model selection, look at the manual before starting, otherwise you will go too long and detour too much.
Pulse + direction. For Siemens 200, it is Q0.0+Q0.2 one axis, Q0.1+Q0.2 two axis, library instructions, if I remember correctly.
I have also used Taiwan Yonghong's, one-axis Y0Y1, two-axis Y2Y3, three-axis Y4Y5, and four-axis Y6Y7.
Delta can't remember clearly, the different models are different (this is very awkward). It seems to be the same as the FATEK above, but there are fewer axles.
ConclusionThis is the end of the related introduction about pulses. I hope this article will give you a more comprehensive understanding of pulses.
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