Table of Contents
MP STUDIO 2 Phase 5 · Memory and Symbols
한국어 | English
An address used in the ladder consists of a memory area name and a number. This page describes the memory areas and their notation, data memory sizes and retentive settings, the symbol table, and how to check which data is used.
Memory Areas
| Area | Name | Use | Basic unit |
|---|---|---|---|
P | I/O | Digital input and output points of the device | Bit |
M | Internal relay | Bits used inside the program | Bit |
D | Data | Numeric values | Word |
T | Timer | Timer current values | Word |
C | Counter | Counter current values | Word |
R | Real | Decimal values (1 = 2 words) | Real |
The range of I/O addresses differs from model to model. If you use an I/O address that the model does not have, the cell turns red.
Bit, Byte, Word and Double Word Notation
The same memory can be read and written in units of bits, bytes (B), words (W) or double words (D). Put the unit letter in front of the area name.
| Area | Bit | Byte | Word | Double word |
|---|---|---|---|---|
| P | P0 | BP0 | WP0 | DP0 |
| M | M0 | BM0 | WM0 | DM0 |
| D | — | BD0 | D0 | DD0 |
| T | — | BT0 | T0 | DT0 |
| C | — | BC0 | C0 | DC0 |
| R | — | — | — | R0 (real) |
Eight bit addresses make one byte. For example, P0 to P7 are BP0, and P32 to P39 are BP4. Double word numbers overlap in word steps: DD0 occupies D0 and D1, and DD1 occupies D1 and D2. Be careful not to use overlapping double words together.
System Bits and User Variables
| Notation | Meaning |
|---|---|
@n | A pulse that is ON for one scan every n×10 ms. Example: @100 is ON for one scan every second. |
@Fn | A blink that toggles ON/OFF every n×10 ms. Example: @F100 has a 2-second period. |
#name · ##name · ###name | User bit, word and double word variables used by name |
Data Memory
Select Setting → Data Memory to open the Data Memory window, where you set the size of each area and the retentive ranges.
- ① Available data: the remaining memory (WORD) and the total size. If it is below 0 it is shown in red, and you need to reduce the area sizes.
- ② Size (WORD): the sizes of the M, D, C, T and R areas.
- ③ Retentive (EEPROM) range: check Use and enter the start and end numbers to keep the values in that range when the power is turned off.
- ④ EEPROM update cycle: how often the retentive values are written to EEPROM (×10 ms; 100 = 1000 ms).
- ⑤ USER and SERIAL: the user memory used by function blocks (USER MEMORY) and the send and receive buffer size of each serial channel.
- ⑥ Default: returns to the default sizes of the current model.
The data memory settings are saved with the project. If you use an address outside the area size (for example a D number beyond the D area size), the cell turns red and you cannot download or monitor.
When You Change the Model
When you change the model in the Device Select window, check Reset the data memory sizes to this model's defaults. to change the memory sizes to the defaults of the new model as well. If you leave it unchecked, the current settings are kept.
For MPA models, select ① MPA, then choose ② Model and ③ the expansion modules (Analog Input X to X5, Analog Output Y to Y4, PT100Ω Input F to F5, Pulse Output K to K4). ④ Device Name shows the name including the module configuration (for example MPA-16A16R(T)-X), along with the CPU and the P area size. If you choose a combination that cannot be fitted, the reason is shown at the bottom of the window.
Symbol Table
Symbols are names and descriptions attached to addresses. Select Setting → Symbol or click the Symbol button in the top band to open the SYMBOL TABLE window.
- Choose an area in ① the memory area tabs (P Memory, M Memory, D Memory and so on) to show only the symbols of that area. The number next to a tab is the number of registered symbols.
- In ② the add row, enter the address, symbol name and comment, and click Add (Enter).
- Type in ③ Text Search to show only the matching symbols.
- Click a cell in the table to edit a registered symbol. Select a row and press
Deleteto delete it. - Use ④ Import and Export at the top to read or save a CSV file. When importing, choose whether to Merge with the current table or Replace it.
- Changes are applied to the project only when you click OK. The number of symbols to be saved is shown at the bottom of the window.
Symbols of addresses that are not used in the ladder are marked Not used in ladder. If the same symbol name is used for several addresses, or a name cannot be used, the number of entries to review and the reason are shown.
Showing Symbols on the Ladder
Turn on View → Show Symbols and View → Show Comments to show symbol names and comments above and below the cells.
Used Data
Select Run → Used Data or click the Used button in the top band to open the Used Memory window. In the memory grid of each area you can see which locations the program uses.
- ① Area tabs: choose the area to view: M Memory, T Memory, D Memory, C Memory or R Memory.
- ② Used cells: the bits used by the program are filled in. In the figure,
D0toD2are in use. - ③ Usage count: the number of used bits, the total number of bits in the area, and the number of rows.
Hover over a grid cell to see its address. Use Rows shown at the top right to change how many rows are visible at once. Use this window to check that a new address does not overlap with locations already in use.
Related Pages
- MPS Series and MPA Series — I/O point names of each product