What is a fieldbus? What are the commonly used bus cables?
According to the interpretation of IEC: Fieldbus refers to a digital, serial, multi-point communication data bus between field devices installed in the manufacturing or process area and automatic devices in the control room.
The current mainstream field buses include PROFIBUS, CANBus, DeviceNet, CC-Link, KNX/EIB, FOUNDATION Fieldbus, AS Interface, RS485 and other products. Zhaolong can provide these high-quality bus cables to customers.
What is the rated voltage, withstand voltage and spark voltage?
Rated voltage: the reference voltage for cable design and electrical performance test, that is, the maximum voltage that the cable is allowed to apply during long-term work. The rated voltage is expressed by Uo/U, and the unit is volts (V).
Withstand voltage is to apply a voltage value higher than a certain multiple of the rated voltage on the insulation of the finished wire and cable, and keep it for a certain period of time without insulation breakdown. For signal control cables and power cables, each product must undergo such a test before leaving the factory.
Spark voltage: Check if there is any leakage of copper or skin impurities in the insulation. The spark tester periodically loads the set voltage value on the insulated wire according to a certain rule, while the conductor part is grounded, so that a voltage difference is formed between the conductor and the insulation surface, so that it can detect whether the insulation layer is defective and ensure the wire and cable products Qualified delivery.
How to choose Mitsubishi servo cables?
Compared with other well-known manufacturers, there are relatively fewer Mitsubishi's servo models. Generally, the most common ones in the market are J2 and J3 series, which are the most widely used. J3 series is a relatively complete series, even the servo cables used in J4 servo series is still the J3 model.
After talking about the servo models, each manufacturer will have some subtle differences in cable models. For example, for power cables, the low-power cables generally use a 4-core 0.5 square structure, the medium-power cables generally use 0.75 square, and the large-power i gcables use 1.0. The encoder cables are simpler, usually in a 6-core 24AWG or 0.2 square structure, and the core wire adopts a twisted structure. Among them, in order to save costs, some manufacturers use 5-core structures. Because of the RS232 communication protocol, only the 5-core structure can be used, and one core is used for short connection. Of course, it is recommended not to save that core in the actual selection, because there will inevitably be accidents in the actual use process, so the extra core can be temporarily used as a substitute.
Notes for the applications of servo drag-chain cables?
The first is to choose the brand and the second is to choose the performance margin. We all know the brand choice, but the price is also relatively high. The original servo cable is several times more expensive than the ones in the market. The second is to have more performance options while choosing domestic brands. For example, we can choose CAT5 servo cables for fixed installation applications, whose service life is much longer. If you choose flexible installation, it is recommended to use drag-chain cables with service life from 300 to 500 times. Generally, the price of this cable is not too high, after all, its process has been very mature. Finally, when choosing this kind of cables, you still have to choose a brand that everyone has trusted, and let the manufacturer provide the corresponding drag-chain test report, performance test report, etc.
How to choose the color of the servo cable and what are the common colors in the market?
The colors of servo cables are generally green, orange, black and gray. The specific cause of color confusion is caused by the different styles of manufacturers. For the European style, orange is generally used to distinguish servo power cables and green is used to distinguish encoder cables. The Japanese style is relatively simple. Black is mostly used in whether the power cables or the encoder cables. The advantage is to reduce the cost, but the disadvantage is that it is not easy to distinguish the cables on site. The domestic servo cables develop late, so we use the colors of Japanese and European styles to distinguish them.
Why white marks are left on the sheath of the bending servo cables?
There are several reasons as follows: 1. Selection of sheath materials. Common servo materials include PVC and PUR. The LSZH materials are not bending resistant, so no discussion will be made here. To put it simply, PVC is divided into oil-resistant PVC and non-oil-resistant PVC. Oil-resistant PVC will not have creases in this case, because the material is very soft and of excellent flexibility, and the cross section is very bright and smooth. In contrast, non-oil-resistant PVC, which will go whitening and whose cross section will not shine, is generally not recommended for use. This kind of sheath materials has a short service life when used in the servo motor, less than two or three months to be replaced. PUR, on the other hand, rarely produces creases unless the sheath material is very thin. The servo cables of Zhaolong are generally made of oil-resistant and bendable modified PVC, which have been tested by a third party and have high performance. The maximum life of the drag chain is up to 20 million times.
What are the types and slections of servo cables?
The servo cables we generally mentioned are mostly industrial servo cables, and commercial ones are not discussed here. Industrial servo cables generally require the characteristics such as oil resistance, high temperature resistance, drag chain, etc. Additional high temperature resistance are required for some special parts of the servos, which may require to use materials such as Teflon.
Industrial servo cables generally include: servo power cables, servo encoder/decoder cables, IO control cables, Ethernet cables, and some bus cables (RS485/RS422/USB/CAN cables, etc.).
According to the occasion of use, there are fixed laying and flexible applications for industrial servo cables. In some occasions, the cables are needed to be used in robot arms, which is not discussed here. Among them, fixed laying accounts for the largest proportion, which has the highest cost performance. Servo cables for drag chain applications include low speed and high speed. The service life of low-speed drag chain cables is generally 5 million times, and that of high-speed drag chain cables is mostly 10 million times. Some manufacturers have introduced servo cables with 20 million times, which we generally do not recommend, because the price is high and the cost performance is low. Servo cables that can actually reach 20 million times generally use alloy wires or copper foil wires as conductors, correspondingly the resistance will increase.
There are many types of IO control cables in the market, which will not be described in detail here.