IS220PDIAH1A燃機卡件
解釋COMREQ狀態(tài)字在解釋COMREQ的內(nèi)容時，需要記住以下幾點：
狀態(tài)字：1.以十六進制形式顯示狀態(tài)字，以便更容易區(qū)分高和低字節(jié)。這樣做的一個好方法是使用“移動單詞”功能塊來顯示梯形圖程序中的十六進制值。
2.FIP總線控制器永遠不會向PLC CPU。在發(fā)出
COMREQ函數(shù)，然后檢查非零值，表明FIP總線控制器正在響應COMREQ。這樣做的一個好方法是使用移動字功能塊將COMREQ狀態(tài)字歸零。
3.低字節(jié)中的狀態(tài)碼1和高字節(jié)中的0表示請求是成功的。所有其他非零值表示錯誤。有關主要和次要錯誤代碼的完整列表，請參閱附錄B中的表格。開發(fā)控制COMREQ執(zhí)行的邏輯時必須小心
作用每個梯形圖計劃，無論是在開發(fā)階段還是在運行階段
階段，應在啟動COMREQ功能之前執(zhí)行以下操作。在下面例如，昵稱用于使程序更易于遵循。
示例邏輯說明了這些要點：
1.使用單觸發(fā)過渡線圈或觸點啟動COMREQ功能。這防止多次發(fā)送相同的COMREQ命令塊。
2.在總線控制器狀態(tài)字中至少包括總線控制器OK位作為COMREQ功能的聯(lián)鎖觸點。您可以添加更多的聯(lián)鎖。
3.將COMREQ狀態(tài)（CRS）字以及OK和FT的字位置歸零啟動COMREQ之前COMREQ功能塊的輸出。
4.將COMREQ的命令代碼和參數(shù)移動到存儲器中COMREQ功能塊輸入中指定的位置，在COMREQ之前
啟動功能。在示例邏輯中：第1級：輸入FIPIFOK（FIP總線控制器狀態(tài)位的第16位）監(jiān)控FIP
總線控制器。如果可以發(fā)送COMREQ，則健康線圈打開。健康用作梯級3-6的聯(lián)鎖裝置。
橫檔#2：輸入BEGREAD觸發(fā)READREQ，從而執(zhí)行移動以及COMREQ功能。READREQ是一個單觸發(fā)線圈，在BEGREAD時激活一次從關閉轉換為打開。
Interpreting the COMREQ Status Word
There are several points to remember when interpreting the contents of the COMREQ
Status word:
1. Display the Status Words in hexadecimal form to more easily differentiate the high and
low bytes. A good way to do this is to use a MOVE WORD function block to display
the hexadecimal value within the ladder program.
2. The FIP Bus Controller will never send a zero for the COMREQ Status Word to the
PLC CPU. The program should zero the COMREQ Status word before issuing the
COMREQ function and then check for a non-zero value indicating that the FIP Bus
Controller is responding to the COMREQ. A good way to do this is to use a MOVE
WORD function block to zero the COMREQ Status Word.
3. A status code of 1 in the low byte and 0 in the high byte indicates that the request
was successful. All other non-zero values indicate errors. Refer to the tables in Appendix B for a complete listing of major and minor error codes.Care must be taken in developing the logic that controls the execution of the COMREQ
function. Every ladder program, whether in the developmental phase or the operational
phase, should do the following before initiating a COMREQ function. In the following
example, Nicknames are used to make the program easier to follow.The example logic illustrates these important points:
1. Initiate the COMREQ function with a one-shot transitional coil or contact. This
prevents sending the same COMREQ Command Block more than once.
2. Include at least the Bus Controller OK bit in the Bus Controller Status Word as an
interlock contact for the COMREQ function. You may add more interlocks.
3. Zero the word location for the COMREQ Status (CRS) word, and OK and FT
Outputs of the COMREQ Function Block before initiating the COMREQ.
4. Move the command code and parameters for the COMREQ into the memory
location specified in IN input of the COMREQ Function Block before the COMREQ
function is initiated.
In the example logic:
Rung # 1: Input FIPIFOK (bit 16 of the FIP Bus Controller Status bits) monitors the FIP
Bus Controller. If it is OK to send a COMREQ, the HEALTHY coil is ON. HEALTHY is
used as an interlock for Rungs 3-6.
Rung # 2: Input BEGREAD triggers READREQ, which enables execution of the MOVE
and COMREQ functions. READREQ is a one-shot coil, activating once when BEGREAD
transitions from OFF to ON.
