Today, I will introduce a national invention authorized patent-a high-voltage isolated DC voltage and current transmitter. The patent was applied for by Nanjing Guodian Nanzi Rail Transit Engineering Co., Ltd., and the authorization was announced on January 4, 2016. The invention relates to a device for measuring voltage and current of high-voltage direct current systems such as subways and light rails, and in particular to a high-voltage isolated direct current voltage and current transmitter. With the development of rail transportation such as subways and light rails, the application of DC systems has become more and more extensive, which brings about the problems of DC voltage and current measurement. When the DC analog signal is isolated by linear optocoupler, the cost is relatively high, and the isolation voltage is limited, which cannot meet the safety requirements. For example, in CN201928261U, a circuit used to isolate analog signals, the linear triangle wave is a method of generating a sawtooth wave through the 555 circuit. The sawtooth wave is realized by the filtering of the square wave. Due to the charge and discharge characteristics of the capacitor, the sawtooth will be generated. The wave is not linear, which will cause the duty cycle of the subsequent PWM to be also not linear, thus introducing errors into the system. PWM is a method of digitally encoding the analog signal level. Through the adjustment of the duty cycle, the level of a specific analog signal is encoded. As long as the bandwidth is sufficient, any analog signal can be encoded using PWM. Especially suitable for DC voltage conversion, the output voltage can be controlled by adjusting the duty cycle. The PWM signal is a complete digital signal, which can easily realize signal isolation. However, in the circuit of PWM encoding and PWM to DC voltage, the duty ratio of PWM and the value corresponding to the output voltage usually present a non-linear state, and this non-linear state will cause the accuracy of the PWM at work to decrease . Aiming at the problems in the prior art, the purpose of the present invention is to provide a high-voltage isolated DC voltage and current transmitter. The technical solution of the present invention is: a high-voltage isolated DC voltage and current transmitter, including a transmitter body and a signal processing circuit, the signal processing circuit is composed of a fixed frequency pulse generating circuit, a linear triangular wave generating circuit, a sampling signal modulation and amplifying circuit, Photoelectric isolation circuit, DAC conversion circuit and V/I conversion circuit. The fixed-frequency pulse generating circuit is connected to a linear triangular wave generating circuit; the triangular wave generating circuit and the sampling signal modulation and amplifying circuit are respectively connected to a comparator to form a PWM wave; the PWM wave is connected to a photoelectric isolation circuit; the photoelectric isolation circuit is passed through Schmidt The trigger is connected with the DAC conversion circuit; a voltage output of the DAC conversion circuit is connected with the V/I conversion circuit. The above-mentioned high-voltage isolated DC voltage and current transmitter is further characterized in that: the linear triangle wave generating circuit uses a constant current source to control the charging speed of the capacitor on the basis of the generated fixed frequency square wave. Under the action of a fixed frequency square wave, rapid discharge is realized. It is further characterized in that: the DAC conversion circuit is a dual-channel PWM input DAC chip, which realizes PWM to 1-5V voltage output and 4-20mA current output. The invention realizes that the sampled signal of ±60mV is converted into a standard control signal of 1-5V or 4-20mA, and the corresponding isolation optocoupler and power supply are selected according to the isolation level and requirements, and the isolation of up to 10KV can be achieved. At the same time, the delay of signal output is reduced, the system error is reduced, and the measurement result is more accurate. Solder Cup Waterproof D-Sub Connector
The Solder Cups D-sub connector, also known as Solder Cups D-sub connector , typically contains a pin layout of 9 pin, 15 pin, 25 pin, 37 pin & 50 pin positions housed in increasing shell sizes accordingly. They are available in both male (plug) and female (socket) variants with the male signal contacts/pins (current rating of 5A) spaced every 2.76mm in horizontal rows and the spacing of rows vertically at 2.84mm laid out half the distance between pins of existing rows.
IP66 IP67 Rated Waterproof D-Sub Panel Mount Solder Connectors
Antenk offer a wide range of waterproof standard density and high density male and female high density D-Sub connectors solder cup with stamped and formed Contacts in cable mount used in a variety of demanding applications.
Antenk's Solder Cup D-Sub Connectors Stamped contacts
FEATURES
Solder cup d-subs available in industry sizes/positions
Low cost economy series.
Nickel shells have indents to provide grounding and additional retention.
Low cost & high performance, non-removable stamped contacts.
Optional mounting hardware available.
Antenk's SOLDER CUP D-SUB CONNECTORS Stamped contacts
MATERIALS
Shell: Steel, Tin or Nickel Plated
Insulator: Glass-filled thermoplastic. U.L. rated 94V-O
(230°C process temp)
Stamped contacts: Male pins - Brass | Female pins - Phosphor bronze
Plating: Gold flash on entire contact (contact us for other plating options)
Solder Cup Waterproof D-Sub Connector Stamped & Formed Contact, Solder Cup Waterproof D-Sub Connector Machined Contacts, Waterproof Panel Mount Solder Cup D-Sub Connector ShenZhen Antenk Electronics Co,Ltd , https://www.antenkelec.com
Harsh outdoor or indoor environments can destroy electronic equipment. Standard D-sub connectors are not intended to withstand contaminants such as water and dust. These waterproof solder cup connectors are available in male or female genders and DB9, DB15, DB25, and HD15 sizes. They will accommodate wire ranges from 30 - 20 AWG. Construction features gold plated brass contacts, nickel plated steel shells, and a silicone insulating ring. Maximum recommended panel thickness is 0.078".