Omron NT31 NT31C manual Host Link NT Link, Features of the Direct Connection Function

Communications with the Host Section 1-4

Features of the Direct Connection Function

1-4-2 Host Link

1-4-3 NT Link

The NT31/NT31C can directly write to and read from such allocated bits and words to change the display status of the elements on the 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 with- out using a PC program is called the direct connection function.

The words and bits allocated for direct connection are called the allocated words and allocated bits.

The direct connection function allows the data to be displayed at the NT31/NT31C to be read from the memory area in the PC and written to memory tables in the NT31/NT31C. Also, the data input at the NT31/NT31C can be writ- ten to the memory area in the PC. The NT31/NT31C screen can be changed in accordance with statuses in the PC memory area, and the NT31/NT31C’s status data can be written to the PC’s memory area.

NT31/NT31C PC

DM area I/O relay area

Auxiliary relay area Timers/counters

The direct connection function has the following features.

•The bits and words referring to operating status and work instruction informa- tion and those for storing input data can be freely allocated to almost any area of the PC memory.

•Since the NT31/NT31C can directly refer to PC bit and word data without using the program at the PC, it can be connected to the PC without changing the PC program which controls the currently running production line.

•The area to control and notify the NT31/NT31C statuses, including display screens, display/no display status, and buzzer output, can be freely allocated to any part of the PC data area. This means that the PC status can be read and controlled just by reading this area at the PC side, without preparing a special communication program.

The direct connection function allows the NT31/NT31C to directly read and write almost all bits and words in the PC and to automatically change the NT31/NT31C screen display. This function can reduce the load on the PC so that its program development efficiency is improved.

The host is connected to a PT in a 1:1 connection, and the words and bits of the host are read and displayed by host link communication. This method can be used for connection to the majority of PC types.

NT link is a method for high-speed communication with a PC using the direct connection function. The PCs that can be connected with the NT link are as fol- lows.

•When using the built-in host link function of a CPU unit or SRM1:

CPM1, CPM2A, CPM2C, CQM1, CQM1H, C200HS, C200HX/HG/HE(-Z)E, CS1G/CS1H-E(V1), CVM1/CV-series PC (-EV1 or later version), SRM1

Besides the 1:1 NT Link method, in which one PC is connected to one PT, the NT31/NT31C can also use the 1:N connection NT Link method, which allows a maximum of eight PTs to be connected to one PC port.

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