Why can't the 475 handheld communicator communicate with the pressure transmitter normally
The 475 handheld communicator and the pressure transmitter cannot communicate normally due to improper use of the handheld communicator, faulty transmitters, problems with the handheld communicator and mismatched communication addresses. In this article, the 475 handheld communicator and the pressure transmitter In-depth interpretation of the reasons for the inability to communicate normally.
1. Improper use of the 475 handheld terminal. The handheld terminal must be connected to the transmitter input or both ends of the load. The load resistance is not less than 250Ω; it cannot be connected to both ends of the power supply, because the low impedance of the power supply is equivalent to the same end point. , The handheld communicator will not be able to read and store information from the transmitter. The communication protocol of the transmitter is inconsistent with the communication protocol of the handheld programmer, which is also the main reason that the two cannot communicate.
2. The pressure transmitter is faulty. The handheld communicator displays "communication error" in the communication, which means that the self-check of the handheld communicator has passed and the fault lies in the transmitter. The polarity of the transmitter's power supply is not reversed. The following problems may be caused. ①The power supply part of the transmitter is damaged. Due to the inability to supply power normally, the transmitter cannot complete the communication and the power module needs to be replaced. There is a diode on the terminal block of the transmitter. When the diode is broken down or damaged and cannot supply power normally, the transmitter will not be able to communicate. The communication can be restored by replacing the terminal block. ②The circuit board of the pressure sensor diaphragm box of the pressure transmitter is damaged. Most of the pressure transmitter is impacted by strong current such as lightning strikes, which damages the circuit board and makes it impossible to communicate with the handheld communicator. This failure cannot be repaired and can only be scrapped. ③The circuit board fails to complete the communication work, and some are accompanied by high alarms. At this time, the circuit board needs to be replaced. The pressure transmitter whose parts have been replaced must be verified and calibrated before it can be used. ④The field conditions do not meet the requirements for use. The circuit load resistance is too large or too low. Check whether the resistance is lower than 250Ω. The field wiring is incorrect. Check whether the wiring polarity and connection are normal. Check whether the cable shield is grounded at one end of the control system. The loop voltage and loop current of the transmitter are insufficient. Check whether the voltage is lower than 12VDC and the current is lower than 4mA.
3. The most common is that the battery pack of the handheld communicator has no electricity, and the battery pack can be removed for charging. There is a problem with the wire of the Communicator. Check or replace the wire. When the 475 Communicator has crashed and cannot be shut down by the normal shutdown method, you can press and hold the Fn + Bulb key for a few seconds to shut it down. Do not pull out the battery to shut it down. The 475 handheld communicator often crashes, you can reinstall the firmware and software from the system card, that is, RE-FLASH operation; when the fault still exists, you can reinstall the 475 handheld communicator's operating system, system software and applications, that is, RE- IM-AGE operation, RE-IMAGE operation function is only available for 475 handheld communicators version 2.0 and above. Steps: Go to the Main menu→Settings→About HART475 of the 475 Communicator; select RE-FLASH or RE-IMAGE→YES. After pressing OK to start, wait patiently. RE-FLASH takes about 20 minutes, and RE-IMAGE takes about 50 minutes. After the operation is completed, there will be a prompt on the screen, just follow the prompts. The charger must be plugged in during operation, because this operation consumes power. During operation, disable the standby and automatic shutdown timers, otherwise it may cause serious consequences that cannot be repaired. The touch screen can be calibrated when the touch pen cannot operate the 475 handheld communicator. Steps: Enter the HART475 Communicator Main menu→Settings, delete the key to enter the next menu→Touch Screen Alignment, press the Delete key to enter the calibration interface, a cross symbol will appear in the center of the screen, use the touch pen to point the cross symbol, the cross symbol It will appear in 5 positions in sequence. After clicking the cross symbol with the stylus, the touch screen can return to normal.
4. The communication address is incorrect. Check whether the pressure transmitter is set to a non-zero address and is in the polling multi-point loop mode. The polling mode of the 475 Communicator can be set to use address polling. Set it to "0" for polling. Inquiry for non-multipoint loops. The polling address or tag number does not match the pressure transmitter, and the incorrect polling address will also fail to communicate. Check whether the communication between the pressure transmitter and the 475 handheld communicator is prohibited by the control system. By stopping the HART communication of the control system, the communication between the 475 handheld communicator and the pressure transmitter can be restored to normal.