NT21_Reference Manual (V069-E1-1) (986756), страница 8
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Make the settings in accordance with the communication method that can be used with the PC to be connected and the conditions atthe operation site.Reference: When using an RS-232C/422A Adaptor (NT-AL001) with the host link or 1:1 NTLink communication method, RS-485 cannot be used. The connection must bemade with RS-232C or RS-422A.25SectionCommunications with the Host1-41-4Communications with the HostThe NT21, NT31/NT31C, or NT631/NT631C is connected to the host by one ofthe following four communication methods.The following communications can be used to connect an OMRON PC:• Host link• 1:1 NT Link• 1:N NT Link (standard or high-speed)The following communications can be used to connect another companies’ PC:• Communications protocol supported by the other company’s PC(NT31/NT31C or NT631/NT631C only)The following communications can be used to connect RS-232C/RS-422 devices, such as factory computers:• Memory linksIn all of these communication methods that can be used with NT21,NT31/NT31C, or NT631/NT631C, data communication with host is by directconnection (Memory link is, however, a quasi-direct connection).In the following, the host link and NT Link that carry out the direct connection willbe discussed.
Memory link will be explained in section 1-5 Communication byMemory Link.1-4-1 Direct Connection FunctionWith the NT21, NT31/NT31C, or NT631/NT631C, the bits and words used to access data required for display, and those for storing input data, can be allocatedin any part of the PC memory area.The NT21, NT31/NT31C, or NT631/NT631C can directly write to and read fromsuch allocated bits and words to change the display status of the elements onthe PT screen, control the PT operating status, and notify statuses to the host.This function, which directly reads and writes the statuses of words and bits without using a PC program, is called the direct connection function.The words and bits allocated for direct connection are called the allocated wordsand allocated bits.The direct connection function allows the data to be displayed at the PT to beread from the memory area in the PC and written to memory table entries in thePT.
Also, the data input at the PT can be written to the memory area in the PC.The PT screen can be changed in accordance with statuses in the PC memoryarea, and the PT’s status data can be written to the PC’s memory area.PTPCDM AreaAR AreaFeatures of the DirectConnection Function26IR/CIO AreaTimer/Counter AreaThe direct connection function has the following features.• The bits and words used to access operating status and work instruction information and those for storing input data can be freely allocated in almost anyarea of the PC memory.• Since the PT can directly access PC bit and word data without using the program at the PC, it can be connected to the PC without changing the PC program that controls the currently running production line.Communications with the HostSection1-4• The area to control and notify the PT statuses, including display screens, display/no display status, and buzzer output, can be freely allocated in any part ofthe PC data area.
This means that the PC status can be read and controlledjust by reading this area at the PC side, without preparing a special communication program.The direct connection function allows the PT to directly read and write almost allbits and words in the PC and to automatically change the PT screen display.
Thisfunction can reduce the load on the PC so that its program development efficiency is improved.1-4-2 Host LinkThe host is connected to a PT in a 1:1 connection, and the words and bits of thehost are read and displayed by host link communication. This method can beused for connection to the majority of PC models.1-4-3 NT LinkNT Link is a method for high-speed communication with a PC using the directconnection function. The PCs that can be connected with the NT Link are as follows:CPM1, CPM2A, CPM2C, CQM1, CQM1H, C200HS, C200HX/HG/HE(-Z)E,CS1 (V1), CS1-H, CJ1, CJ1-H, CVM1/CV-series PC (-EV1 or later version),SRM1Besides the 1:1 NT Link method, in which one PC is connected to one PT, theNT21, NT31/NT31C, and NT631/NT631C can also use the 1:N connection NTLink method, which allows a maximum of eight PTs to be connected to one PCport.PCs that can be connected with the 1:N connection NT Link method are as follows: CQM1H, C200HX/HG/HE(-Z)E, CS1 (V1), CS1-H, CJ1, and CJ1-H.The NT21, NT31/NT31C, and NT631/NT631C also support OMRON’s highspeed 1:N NT Link that provides faster 1:N communications.
The only PCs thatsupport the high-speed 1:N NT Link are the -EV1 and higher versions of theCS1, the CS1-H, the CJ1, and the CJ1-H.In the following sections, the term NT Link is used to refer to the NT Link communication method in general, the term 1:1 NT Link is used to refer specifically toNT Links with a 1:1 connection, and the term 1:N NT Link is used to refer to bothstandard and high-speed NT Links with 1:N connections. When necessary, thestandard 1:N NT Link is distinguished from the high-speed 1:N NT Link.Features of the NT LinkThe NT Link has the following features.• High-speed communications with specific models of PCs can be executed.The NT21, NT31/NT31C, and NT631/NT631C also support OMRON’s highspeed 1:N NT Link.• Writing in units of bits to the PC memory area is possible.This enables the other bits of words allocated for a touch switch to be allocated for other purposes (e.g.
a lamp).However, since data is written to the DM Area in word units, the other bits ofwords allocated for touch switches in the DM Area cannot be used for otherpurposes.• The NT Link can be used even when the PC is in the RUN mode. (When thehost link method is used, the PT switches to the monitor mode when the PC isin the RUN mode.)• In the case of PTs that support the standard 1:N NT Link (NT20S, NT21, NT30,NT30C, NT1, NT31, NT31C, NT600S, NT620S, NT620C, NT625C, NT631,NT631C) up to 8 PTs can be connected to one port of the PC and used at the27SectionCommunications with the Host1-4same time. Up to 8 PTs (NT21, NT31, NT31C, NT631, and NT631C) can alsobe connected simultaneously when the high-speed 1:N NT Link is being used.All of the PTs connected to a PC port must use either the standard or highspeed 1:N NT Link; the two communications systems cannot share a singleport.• When using a C200HX/HG/HE(-Z)E PC and standard 1:N NT Links, up tothree 1:N NT Link systems (i.e., 24 PTs) can be connected by installing a communication board in the option slot of the CPU.
For details on the communication board, refer to the SYSMAC Serial Communications Board OperationManual (W304-E1-j).• When using a CQM1H PC and standard 1:N NT Links, multiple 1:N NT Linksystems can be connected by installing Serial Communications Boards in theInner Board slots. For details on the Serial Communications Board, refer to theCQM1H Serial Communications Board Operation Manual (W365-E1-j).• When using a CS1, CS1-H, CJ1, or CJ1-H PC, multiple 1:N NT Link systems(standard or high-speed) can be connected by installing a Serial Communications Board in the Inner Board slot or installing a Serial Communications Uniton the Backplane.
For details on the Communications Board/CommunicationsUnit, refer to the CS/CJ Series Serial Communication Board/Unit OperationManual (W336-E1-j).• If the PC being used supports the Programming Console function, the NT21,NT31/NT31C or NT631/NT631C can be used as a Programming Console.• If the PC being used supports the Device Monitor function, the NT31/NT31C orNT631/NT631C can be used to change the PC’s operating mode and read/change data in the PC’s memory areas.
(The NT21 does not support the device monitor function.)The NT Link is compatible with the host link. The PT screen data and PC programs used with the host link direct connection method can be used with the NTLink method as they are.1-4-4 Functions of the Allocated Bits and WordsWords and bits in the PC can be allocated to elements displayed on the PT andPT status when using the direct connection function. By changing the contentsof the bits and words, the PT can be controlled from the PC. It is also possible tosend data to the PC by pressing touch switches at the PT.Controlling the PT fromthe PCThe following PT functions can be controlled from the PC.• Screens:Display of designated screens, confirmation of screen numbers, etc.• Memory table:Writing to a memory table entry, copying from a memory table entry to another memory table entry, etc.• Lamps:Display instructions, confirmation of display status, etc.• Touch switches:Display instructions, confirmation of display status, enable/disable operations, etc.• Numeric inputs, character string inputs, thumbwheel switch inputs:Enable/disable inputs, etc.• System control:Buzzer ON/OFF, display/no display status, screen printing, window open/close status, and other PT status28SectionCommunications with the HostNotification from the PTto the PC1-4Data in the PT is sent to a PC when, for example, a touch switch is pressed.
Thefollowing 5 types of data are sent to a PC.• PT status, screen number of currently displayed screen• The status of touch switch inputs• Numeric values and character string input with the numeral/character stringsetting function using touch switches or a bar code reader.• Changes in memory table entries after copying between memory table entries,etc.• Numerical results of calculations from the mathematical functionFunctions of Display ElementsLamps (page 112)Allocated: BitPTPCLamp #1 (Bit 000100)LitSwitch 1: ON (Bit 000100)UnlitSwitch 2: OFF (Bit 000101)Lamp #2 (Bit 000101)The PC’s bit status is displayed by the lamp at the PT.Normal (standard) lamps come on (flash) when the PC’s bit status (lamp bit) isON (1), and go off when it is OFF (0).With image/library lamps, the displayed image or library data can be switched inaccordance with the ON (1)/OFF (0) status of PC bits (lamp bits).Touch Switches (page 119)Allocated: Bit (lamp bit, notification bit, or interlock bit)PCPTBit 009012: ONTouch switch #12Bit 0090120090121The lamp comes on (flashes) when the PC’s bit (lamp bit) is ON (1) and goesOFF when it is OFF (0).
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