Deltaqpaupi (Ziyaretçi)
| | DE at pin 3 goes high, enabling the driver and causing the differential data on pins 6 and 7 to follow pin 4. When pin 4 goes high logic 1 , pin 6 of Schmitt-trigger inverter 74AC14 goes high. The 0.001pF capacitor charges through the 27k and 390Q resistors. After a short delay, pin 9 of the 74AC14 goes high and DE goes low. DE thus remains high while the line switches to logic 1 and for a short time afterwards. After the delay, pin 3 on the SN75176B goes low, disabling the driver. The data on pins 6 and 7 follows pin 4 as it switches state and remains at a logic 1 after the driver is disabled Figure 6-15 . When the data input goes low again, DE follows, going high to enable the driver. With the components shown, the delay in switching the driver off is approximately 27 ps. Ideally, the delay is half of one bit width. In reality, the computers 101 Chapter 6 Figure 6-16: This retriggerable 1-shot can automatically enable an RS-485 driver. A Start bit or logic 0 results in a pulse of 1.5 word widths. in most networks don’t respond immediately after the Stop bit so a slightly longer delay causes no harm. To reduce the delay, decrease the value of the 27k resistor. Each kilohm of resistance corresponds to approximately 1 ps of delay. The circuit has a small effect on the transmitted RS-485 data. When the data input goes low, the driver’s output switches from disabled to logic 0. When the data input goes high, the driver’s output is already enabled and switches from logic 0 to logic 1. At very fast bit rates or when the bit rates of the transmitting and receiving computers don’t closely match, differing delays in switching the driver on and switching the output of an enabled driver can result in errors when reading data. The transceiver’s data sheet specifies the maximum delays for a specific load. The relevant delays are driver-enable to output and driver input to output. At low to moderate bit rates, the asymmetry is small enough that it causes no problems. Using a prom-electric.ru |
MichaeltLenly (Ziyaretçi)
| | Привет всем!
Вылезла авария al207 на частотнике N3-215-N1. Похожие устройства ATV71WU40N4A24, CIMRF7Z42P21B, CIMR-V7TCB1P57 на компрессорах исправны.
Методику нашел через рамблер по запросу "SKiiP39MLI12T4V1" prom-electric.ru/media/SEMIKRON_DataSheet_SKiiP_39MLI12T4V1_25230510.pdf . Неиcправен был контроллер питания.
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MichaeltLenly (Ziyaretçi)
| | Бодрого дня!
Высвечивается error err9 на преобразователе CFW110211T4ON1Z. Подобные устройства ATV71HD11Y, CIMR-E7Z20151, EI-9011-030H установленные на вентиляции в норме.
Методику нашел через rambler по запросу "ABB ACS310 (En)" prom-electric.ru/media/ACS310SHORTUserManual.pdf . Заменил модуль SKM.
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MichaeltLenly (Ziyaretçi)
| | День добрый!
Вылазит ошибка w130 на частотном преобразователе M400-094002240A. Подобные устройства CIMR-E7C27P51, CIMRE7Z40451A, E1-P7002 175H установленные на двигателях в норме.
Инструкцию нашел в поисковике по запросу "SKiiP11HEB066V1" prom-electric.ru/media/SEMIKRON_DataSheet_SKiiP_11HEB066V1_25230830.pdf . Оказался неисправен микропроцессор.
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