Delta SLC-500, PLC-5, 1770-KF2 user manual Types 0 3 Basic Commands

Powerful Solutions for Digital Plants

Types 0 – 3 (Basic Commands):

These are mainly for PLC-5 backward compatibility to older types of PLC with non-paged memory like PLC-2. The special data fields are not used during configuration. All data (16-bit integer or discrete) are written/read through the PLC-2 compatibility file. The memory address in PLC-5 is assigned with the communication module address. This address is an octal based number which can be set with dip switches on the module. For example, if the KE module has an address of 13 octal (11 decimal), data will be accessed from PLC-5 integer file N11.

The Basic Protected (0) and Basic Unprotected (2) use word address to operate on integer data. The Basic Protected Bit (1) and Basic Unprotected Bit (3) use byte address to operate on discrete or binary data. Since the addressing scheme differs between Basic word and Basic bit commands, the user needs to be cautious in specifying the starting address in the Dataset. For example, if user wants to access bit 0 in word 10 (N11:10), the starting address needs to be 20 to convert word address into byte address. All four commands support both single and block output mode. In single output mode, only the changed bits will be written in addressed byte for Basic Bit write.

Types 4 (Typed Transaction with ASCII addressing) and 8 (Typed Transaction with binary addressing):

The typed transactions treat each data type as an element and automatically adjust the memory address to accommodate the defined element type. Therefore, the starting address points to different memory location depending on the data type. It points to the word address for integer data and double word address for floating point data.

For Binary data type, it points to the word, not the bit, address within the Binary file. The number of element denotes the number of bits to be included in the Dataset starting at the specified word address. The bit position is relative to the starting word address. Therefore, every seventeenth bit will start at the next word. For example, a starting address of 8 with 32 elements means the Dataset starts at the eighth word in the binary file and contains 32 bits. The seventeenth bit will start at the ninth word. The bit position in the PLC is specified by a slash (/) after the word address. Therefore, the first bit in the above Dataset has an address of B3:8/0. Although each Dataset can contain 100 elements, it is recommended that the maximum number to be 96 to ensure the Dataset ends on a word address boundary.

Both single and block output modes are supported for integer, binary, and floating point file type.

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