HIMA F8627處理器模塊,F8627使用指導
RS-485多單元（單個(gè)或一半）需要多點(diǎn)握手雙工）或單單元半雙工配置。這將啟用傳輸驅動(dòng)器
僅當RTU正在傳輸時(shí)。對于RS-232，該模式控制CT與可操作的RS232-to-RS485轉換器兼容的信號在半雙工模式下。啟用多點(diǎn)握手時(shí)，沒(méi)有其他可以握手。
無(wú)線(xiàn)電調制解調器-類(lèi)似于硬件握手，但RTS僅被斷言當RTU有數據要發(fā)送時(shí)。此后，RTU發(fā)送或暫停數據基于CTS線(xiàn)路的傳輸。
無(wú)線(xiàn)電調制解調器模式還提供可選的調制解調器掉頭計時(shí)器
HIMA F8627處理器模塊（TAT）。如果調制解調器在指定的時(shí)間段內沒(méi)有響應RTS線(xiàn)路，則會(huì )刷新傳輸緩沖區，丟棄RTS并丟失幀。TAT是通過(guò)在配置中指定0.25、50、75和1.00之一啟用第二）時(shí)間間隔。將時(shí)間間隔設置為無(wú)將禁用TAT。3.5 DCS主動(dòng)檢測
RTU接口模塊提供了選擇性監測Modbus活動(dòng)的能力主人如果該活動(dòng)下降，則在配置的%I參考（位0）和Modbus異常狀態(tài)字節；此外，DCS LED將開(kāi)始以1秒的速度閃爍。這為CPU、維護操作員和主機提供一種方法，以確定主機是否功能正常。
要啟用此功能，請將DCS配置條目設置為您希望RTU模塊的時(shí)間量在設置指示位之前，等待發(fā)送最后一個(gè)通信幀。超時(shí)值為限制為1到12秒。將超時(shí)值設置為零將禁用此功能。
Multi-drop handshaking is required for RS-485 multiple unit (either single or half
duplex) or single unit half-duplex configurations. This enables the transmit driver
only when the RTU is transmitting. For RS-232, this mode controls the CTS
signal for compatibility with RS232-to-RS485 converters which can be operated
in a half-duplex mode. When multi-drop handshaking is enabled, no other
handshaking is available.
RADIO MODEM - Similar to hardware handshaking with the exception that RTS is only asserted
when the RTU has data to send. Thereafter, the RTU sends or suspends data
transfer based on the CTS line.
The radio modem mode also provides an optional modem turn-around-timer
(TAT). If the modem does not respond to the RTS line within a specified period,then the transmit buffer is flushed, RTS is dropped and the frame is lost. TAT is
enabled by specifying in the confi guration one of the (.25, .50, .75 and 1.00
Second) time intervals. Setting the time interval to NONE disables the TAT.
3.5 DCS Active Detection
The RTU Interface Module provides the capability to optionally monitor the activity from the Modbus
master. Should that activity drop off, a bit is set in both the configured %I reference (Bit 0) and the
Modbus exception status byte; furthermore, the DCS LED will begin to flash at a 1 second rate. This
provides a method for the CPU, maintenance operator and the master to determine if the master is
functioning properly.
To enable this feature, set the DCS configuration entry to the amount of time you wish the RTU Module to
wait after the last communications frame was sent before setting the indication bit. Th e time-out value is
limited to 1 through 12 Seconds. Setting the Time-out value to zero disables this feature.
