Item Reference Syntax

Use item references to access data stored in memory registers in connected devices, as well as to access standard system items in the OI Server itself.

This section only describes the item reference syntax and options for the MELSEC server. For more general information about item references, see "Managing Device Items" and "Item Reference Descriptions" in the Operations Integration Server Manager Help.

Item references in this OI Server use the following syntax.

For Discrete (1-bit) memory registers — i.e., register types X, DX, Y, DY, B, SB, M, SM, L, S, V, F, TS, TC, SS, SC, CS, CC — use the following syntax:

<register type><address>

For Word (2-byte) memory registers — i.e., register types TN, SN, CN, D, SD, W, SW, Z, R, ZR — use the following syntax:

<register type><address>@[data type]

For bit-accessible memory registers and strings — i.e., register types DSH, WSH, RSH — use the following syntax:

<register type><address>.<bit number or string length>

The following syntax diagram shows all of the possible options:

{ register type | X | DX | Y | DY | B | SB | M | SM | L | S | V | F | TS | TC | TN | SS | SC | SN | CS | CC | CN | D | DSH | SD | W | WSH | SW | Z | R | RSH }address { | @ { data type | SHORT | WORD | BCD | LONG | DWORD | LBCD | FLOAT } | . { bit number | string length } }

Where,

register type: The type of memory register on the connected device, such as Input Relay (X), Output Relay (Y), File Register (R), and so on.

address: The address of the memory register on the connected device. This value can be either decimal or hexadecimal, depending on the register type.

data type: The formatted data type of the value read from the memory register. This is optional; if the data type is not specified, the value will be formatted as Word (i.e., unsigned,16-bit decimal) by default.

bit number or string length: The number of the bit to read/write. Bit 00 is the low bit. Bit 15 is the high bit. For string registers like DSH, WSH and RSH, the length of the string is specified here.