Metro rail voltages are commonly used at 750 VDC and 1500 VDC. ISO EMH series rail voltage monitoring dedicated 6000VAC high isolation amplifier, designed for the monitoring system of rail transit circuit PLC.
In the rail transit, the track circuit control system is one of the important equipments for ensuring the driving command automation in the signal equipment. Therefore, the state of the track circuit must be checked frequently to ensure that the track circuit is in a normal state and reliable in operation. Whether the working state of the track circuit is normal can be manifested by monitoring the change of the track voltage. With the development and application of microelectronics technology, especially the programmable controller PLC based on micro-processing technology, integrated computer technology and automation technology, the station signal interlocking control system is gradually replacing the relay type 6502 electric centralized control system. The track voltage test panel is also replaced by the rail voltage monitoring system composed of PLC. The track voltage monitoring system is a contactless control circuit with long equipment life, stable and reliable performance, accurate test data and simple and convenient operation. To test the voltage of the whole station track segment, simply click the loop test button on the track voltage monitoring screen with the mouse, and all the test data is displayed quickly. At the same time, the computer automatically compares the monitored voltage value of each track segment with the set standard voltage value. If the difference between the two is too large, that is, the track voltage is too high or too low, an alarm message is given, and the maintenance personnel are notified to deal with it in advance. Potential failure. The main process flow of the track voltage monitoring system is: the upper computer (workstation) issues the track voltage monitoring command, the lower computer (PLC) receives the command, after the logic operation, sends the address signal to drive the track voltage collector, and strobes a certain acquisition channel. The collected 0~30 volt AC voltage is converted into 0~5 volt DC voltage signal and sent to the PLC system. After logical operation and data processing, the result is put into the data storage area, and the upper computer reads the data on the CRT. display.
ISO 4-20mA-H Current Loop The 6000VAC high isolator is a monolithic two-wire isolated interface chip. The IC includes a current signal modulation and demodulation circuit, a signal coupling isolation conversion circuit, and the like. The small input equivalent resistance makes the input voltage of the IC reach an ultra-wide range (7.5-32V), so that users can realize long-distance, distortion-free transmission of 4-20mA (0-20mA) signals without external power supply. The internal ceramic substrate, printed resistor process and new technology isolation measures enable the device to meet the harsh environmental requirements of 6000VAC insulation voltage and industrial grade wide temperature, humidity and vibration.
Features :
· Standard SIP16 or DIP24 flame retardant package
·Signal input / output 5400VAC isolation voltage
·Input and output do not need external power supply, no external components required
· 4-20mA current input / output accuracy (distortion <0.2%)
·Industrial wide temperature (-45 -+85 °C)
·(7.5-32V) ultra-wide range input voltage
·High linearity (non-linearity <0.2%)
Low impedance (voltage drop <4V)
· Frequency response (small signal bandwidth): 2KHZ (Io = 20mA)
Typical application :
· Analog signal data isolation, acquisition
·Isolation 4-20mA signal transmission
·Industrial field signal isolation
·Ground interference suppression
· Signal long line without distortion transmission
·Instrument signal transmission and reception
·Power monitoring, medical equipment isolation barrier
Track voltage monitoring application plan:
Rail transit control system related product application picture:
