MP STUDIO 2 offers two ways to show values and characters on a 4-digit or 6-digit 7-segment LED module (FND) built on the TM1637 chip.

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• Box mode
  The FINI, FINT and FDATA functions write directly to the chip from the ladder. These are the same functions as in the previous MP STUDIO.
• Screen mode
  You lay out screens in advance in the 7-Segment Screen Editor and show each one with a single FSCR function (V1.3.0 and later). The value fields on a screen follow the values in the PLC memory automatically.
• Simulation
  During simulation, a virtual 7-segment display appears in the editor (V1.3.0 and later).
• Live PLC display
  During monitoring, the editor shows the characters the PLC sent to the chip (V1.3.0 and later).

On this page

• Two Ways to Display
• Supported Products and Connections
• Box Mode (FINI·FINT·FDATA)
• 7-Segment Screen Editor
• Showing a Screen from the Ladder (FSCR)
• Viewing in Simulation
• Viewing the 7-Segment Display on the PLC During Monitoring
• Checks and Warnings
• Examples
• Troubleshooting

The program will not compile if one display uses both modes
Each 7-segment display can use only one of the two modes. If you use box mode functions and FSCR on the same 7-segment display, the box mode cells turn red and the program cannot be compiled (see Checks and Warnings).

The terminals for the 7-segment display and the values to enter for the CLK and DIO arguments of FINI depend on the model. See the product pages in the table for the terminal locations and connector diagrams. For the module types you can use (clock type and decimal-point type) and photos of the modules, see the 7-Segment LED Guide.

On MPS-16A8R(T), the 7-segment display works from V1.3.0 (in earlier versions, the PLC did not output the 7-segment signals).

• In box mode on MPS-8A8R and MPS-16A8R8T, each CLK/DIO pair of an executed FINI gets its own 7-segment display, and FINT and FDATA write to the display of the FINI executed last. MPS-16A8R(T) uses only the one pin pair of the FINI placed last in the program.
• Connect VCC, GND, CLK and DIO of the 7-segment module as shown in the connector diagram on the product page.

A 7-segment display does not work on a standard MPS-8A4T-S
On the standard MPS-8A4T-S, the FND / ENCO connector has 4.7 kΩ pull-down resistors, so a 7-segment display does not work correctly. To use a 7-segment display, choose the 7-segment control option when you order (see MPS-8A4T-S).

Running FINI on an MPA turns off serial 3 communication
On the MPA series, executing FINI switches off serial 3 communication, and serial 3 cannot send or receive until the PLC is restarted.

Box mode writes directly to the 7-segment display with FINI, FINT and FDATA in the 7-Segment category of the Functions panel. The chip is written on every scan in which the rung containing the function is on, and nothing is sent while the rung is off. The chip holds the characters it received, so the last characters stay on the display after the rung turns off.

When FINT or FDATA runs normally, power continues to the right of the function. If an argument is invalid and nothing can be shown, the power to the right is cut.

• On MPS-8A4R(T)-S, MPS-8A8R(T)-S and MPS-16A16R(T), the 7-segment display switches on automatically when the PLC starts if the program has FINT or FDATA, so FINI is not required.
• On other models, the 7-segment display switches on only when FINI runs. If there is no FINI, the FINT and FDATA cells show an orange warning.
• FINI clears digits 1 to 4 every time it runs. If its rung is always on, the digits are cleared and rewritten on every scan, so use a rising edge or a similar condition so that FINI runs only once, when needed.

POSITION (POS) is the chip address plus 1. On a 4-digit module, the chip addresses usually run from 0 to 3 starting at the left, so POS 1 is the leftmost digit and POS 4 is the rightmost. On 6-digit modules, the order of the digits and chip addresses varies by product, so in box mode, check that each character appears in the digit you want.

• With SIGN off, negative values are shown as unsigned numbers. For example, the byte -5 is shown as 251.
• With SIGN on, the sign needs one more digit to the left of the number. POSITION must be greater than LENGTH to show the sign.
• If the value has more digits than are shown, only the lower digits appear (12345 → 2345 with LENGTH 4).
• Double word values and negative values with SIGN on are shown correctly from V1.3.0.

FDATA writes the low byte of DATA as is to the digit at POSITION (1 to 4). Bits 0 to 6 are segments a to g, and bit 7 is the dot. Use it for shapes other than numbers and letters, or to switch individual segments on and off directly.

You can write DATA in any of these forms: 16#3F (hex), 63 (decimal) or 2#00111111 (binary). You can make the values for other characters in the Characters tab of the 7-Segment Screen Editor. To light the dot as well, add 16#80 to the value (for example, 1. = 16#86).

The 7-Segment Screen Editor is a window where you lay out the screens for a 7-segment display on a picture of the real module (V1.3.0 and later).

• Select Settings → 7-Segment Screen Editor.
• Press Enter on an FSCR cell in the ladder, or double-click it, to open the editor with that display and screen selected.
• When you edit an argument cell of FSCR, click Open screen editor below the input box.
• If you add an FSCR when there are no 7-segment displays yet, display 1 is created and the editor opens automatically.
• Right-click an FINI, FINT or FDATA cell and select Show 7-segment display. The editor opens, and its display follows what the 7-segment display is currently showing.

The editor has no OK or Cancel button. Your changes are applied to the project right away, and you can undo or redo them with Ctrl+Z and Ctrl+Y. To keep them in the file, save the project (Ctrl+S). You can keep editing the ladder while the editor is open. Close the window with ✕ or Esc.

• ① Status badge: During simulation or monitoring, shows what the display is showing (Simulation · running · screen N or PLC display · screen N).
• ② LED color · 7-segment only: Choose the LED color of the editor display (red, green, blue, amber or white). The color is remembered only on this PC and does not affect the PLC. 7-segment only shrinks the window.
• ③ 7-segment display list: Add and select 7-segment displays here.
• ④ Display properties: The number, digits, digit order, pins, brightness and style of the selected display.
• ⑤ Screens: The screens of the selected display.
• ⑥ Screen number · Add value field: Change the number of the selected screen, or place a value field at the digit selected on the display.
• ⑦ Value field band: Value fields appear as colored bars. Drag a bar to move it, and drag its right end to change the width.
• ⑧ Display: Draws the characters the PLC will show on the 7-segment display. The digit numbers and chip addresses are shown below the display.
• ⑨ Value fields on this screen: The list of value fields on the screen and the longest time screen mode adds to a scan.
• ⑩ Tabs on the right: Value field (properties of the selected value field), Segments (fixed segments of the selected digit) and Characters (making segment values).
• ⑪ Problem list: Lists any problems in the 7-segment screen definitions.

1. Click ＋ in 7-segment displays on the left (or Add 7-segment display, shown when no display exists yet). A display is created with the lowest unused number, 4 digits, digit order 0,1,2,3, brightness 7 and screen 0.
2. Set the properties in the table below to match the 7-segment module and its wiring.

Click Remove this 7-segment display to delete the selected display. Each entry in the display list also shows its number of digits and screens.

If characters appear scrambled on a 6-digit module, the digit order does not match the module. Many common 6-digit modules are wired with the chip addresses in the order 2,1,0,5,4,3. The digit order is shown below the editor display as chip N.

You can make several screens for one display. In Screens, ＋ adds a screen, ⧉ duplicates it and − deletes it. Screens are identified by number (0 to 255), and you can change the number of the selected screen in Screen number above the display. One display can have up to 255 screens. Press PgUp and PgDn to move to the previous and next screen.

The thumbnails in the list show each screen with its preview values. During simulation or monitoring, the number of the screen currently on the 7-segment display is shown in green.

Click a digit on the display and type a character to put a fixed character (fixed segments) in that digit. The cursor then moves one digit to the right.

• You can use 0 to 9, A b C c d E F G H h I J L n o P q r S t U u y, - _ ° = and a space. A letter that can be drawn in only one case is entered in that shape (a → A, O → 0).
• Typing . switches the dot of the previous character on or off.
• Delete with Backspace and Delete, and move between digits with ←, →, Home and End.
• Characters that a 7-segment display cannot draw (K, M, V, W, X, Z, Korean characters and so on) are not entered, and the reason is shown below the display. Draw such shapes one segment at a time in the Segments tab.

The Segments tab edits the fixed segments of the selected digit one segment at a time.

• ① Fixed segments of digit N: The selected digit and its current value (hex).
• ② Segments: Click a segment to switch it on or off.
• ③ Quick characters: Click a character to apply its shape. Dot switches the dot on or off, and Clear empties the digit.

You cannot write fixed characters in a digit that has a value field. In such a digit, only the dot of the fixed segments lights up along with the value. Use this to light the colon of a clock-type module, or a fixed decimal point, together with a value field.

A value field is a place on the display that shows a value from the PLC memory.

1. Click the digit on the display where the value should start.
2. Click Dec, Hex or Bit text in Add value field above the display. A value field of the default width (4 digits for decimal, 2 for hex and 3 for bit text, or fewer if fewer digits remain) is placed starting at the selected digit. Ctrl+Enter places a decimal value field.
3. Enter an address or a symbol in Address on the Value field tab on the right. Dec and Hex take a byte, word or double word address (for example D10 or DD20), and Bit text takes a bit address (for example M5).
4. Set the options you need.

• If a value does not fit in the width, the whole value field is shown as top bars (‾). In a signed decimal field, a negative value that does not fit is shown as bottom bars (_). If a preview value overflows, the Value field tab shows Overflow — the whole width shows top bars (a cut-off number is never shown).
• Hex values are shown with 0 to 9 and A b C d E F.
• Drag a bar on the value field band to move a value field, and drag its right end to change the width. You can also move it with Alt+←→ and change the width with Alt+Shift+←→.
• To delete a value field, click Remove this value field, or select the value field and press Delete.

Value fields on this screen below the display lists the value fields on the screen with their type, address, digit and width. Click a row to select that value field. The bottom row, Up to ≈ 70 µs per scan · N scans when the whole screen changes, shows the longest time screen mode adds to a scan and how many scans it takes to show the whole screen when every digit changes. With two or more displays, the displays take turns sending, so the number of scans grows accordingly.

The Characters tab is a tool for making the value of one 7-segment digit by clicking segments. It does not change the screen you are editing. Use the buttons at the bottom to choose where the value goes.

• ① Copy digit N from the display: Copies the shape of the digit selected on the display. During simulation or monitoring, it copies the actual character shown on the display.
• ② Painter: Click a segment to switch it on or off.
• ③ Value: The Hex (in the form 16#3F), Dec and Binary values of the shape. Click the ⧉ button to copy a value.
• ④ Bits: Switch bits 7 (dot) to 0 (a) on and off one by one.
• ⑤ Quick characters: Click a character to apply its shape. You can also press a character key to pick it directly (. dot · Del clear · Ctrl+C copy hex).
• ⑥ Insert: With the DATA cell of an FDATA selected in the ladder, click this to put the hex value in that cell. Load into the painter loads the current value of that cell into the painter.
• ⑦ Insert as fixed segments: Puts the shape into the fixed segments of the digit selected on the display.

Ctrl+Enter puts the value into the DATA cell of FDATA if that cell is selected, and otherwise into the fixed segments of the selected digit. You can undo either with Ctrl+Z.

Click 7-segment only at the top of the window to turn the editor into a small window with only the display. Use it to watch the 7-segment display during simulation or monitoring while you look at the ladder. Click Full view to return to the full window.

Screens are shown with the FSCR function (V1.3.0 and later). Choose FSCR: Show Screen in the 7-Segment category of the Functions panel, or type FSCR 1 0 in the Insert Function window (Ctrl+E).

• The screen is shown while the rung is on. When the rung turns off, the last screen stays and its value fields keep updating. You do not need to call it with a pulse, and FINI is not needed either.
• The output of FSCR turns on when the screen is in the screen list and the 7-segment display responds. MPS-8A8R and MPS-16A8R8T do not read the response from the 7-segment display, so on these models the output turns on whenever the screen exists.
• If you use a word address (for example D20) for PAGE, you can switch screens by changing that value. If the number is not in the screen list, the last screen stays on the display and the output turns off.
• If two or more FSCR for the same display are on in the same scan, the screen chosen by the later FSCR is shown.
• When you add an FSCR, DSP and PAGE are filled in with the first display and the first screen. When you edit the DSP or PAGE cell, the displays and screens appear as small pictures below the input box, so you can pick one.
• The screen keeps being sent even while the 7-segment display is not responding. If you unplug the module and plug it back in, the whole screen is sent again within about 1 second.

If you open the 7-Segment Screen Editor during simulation, the editor display shows the characters the simulator sent to the 7-segment display (V1.3.0 and later). Both screen mode and box mode are simulated. For how to start and stop simulation, see Phase 8 · Simulation.

• ① Status badge: Shows the run state and the screen currently showing, as in Simulation · running · screen N.
• ② Display status: Each display in the display list shows On, Off, No response or Pins not set.
• ③ Display: The value field digits show the actual values from the simulator, and the border of the display turns green. Fixed characters are shown exactly as set in the editor.
• ④ Status line: One line below the display shows the screen currently showing and facts about the 7-segment display.
• ⑤ Values: Value fields on this screen shows the characters each value field is currently showing.

At first, the editor follows the screen that is on the 7-segment display. If you select another screen, it stops following, and 7-segment display N is now showing screen M. It differs from screen K, which you are editing. appears below the display along with Go to that screen. Click Go to that screen to follow the screen on the 7-segment display again.

When simulation is off, a Start simulation button appears below the display.

The 7-segment displays that FINI, FINT and FDATA write to are listed under Box mode (FINI, FINT, FDATA) in the list on the left. Select an entry to show that 7-segment display on the editor display in the center (read only). Click a character on the display to copy its shape to the Characters tab.

• In box mode, MP STUDIO 2 cannot tell how many digits the module has. When you select the display, choose the number of digits of the editor display with Digits (4 digits or 6 digits) on the left. This setting is remembered only on this PC.
• Facts about that 7-segment display are shown below the display, for example The number is longer than the digits to show (LEN), so only the lower digits appear — the PLC does the same. or FINI has not run yet, so the 7-segment pins are not set up — FINT and FDATA before that do not reach the chip.

If you open the 7-Segment Screen Editor while monitoring a real PLC, the editor display shows the characters the PLC sent to the 7-segment display (V1.3.0 and later). The status badge shows PLC display · screen N, and From the 7-segment display buffer in PLC RAM — exactly what was sent to the chip appears below the display.

• ① Status badge: Shows PLC display · screen N while the editor shows the 7-segment display of the PLC.
• ② Display status: Each display in the display list shows its state, such as On.
• ③ Display: Shows the characters the PLC sent to the chip, with the actual values from the PLC in the value fields.
• ④ Source line: From the 7-segment display buffer in PLC RAM — exactly what was sent to the chip shows where the characters come from.
• ⑤ ACK notice: On models that do not read the chip response, This model does not read the chip response (ACK), so a disconnected chip cannot be detected — the screen is re-sent every second. is shown.

• The PLC also keeps the characters it sent to the 7-segment display in its memory. MP STUDIO 2 reads and shows those values, so they may differ from what the 7-segment module actually shows (a faulty module or a wiring error cannot be detected).
• The characters are shown only when the program on the PLC is confirmed to be the same as this project. If it is different or cannot be confirmed, the display is not drawn and the reason is shown instead.
• The values are read only while the editor is open. With two or more displays, they are read one display at a time in turn, so the more displays there are, the slower the updates.
• If you edit value fields during monitoring, only the value fields you did not edit show the actual values from the PLC, the border of the display becomes dashed, and The value fields you edited are not on the PLC yet, so they are drawn with preview values. is shown. Your changes reach the PLC only after you download them.
• On models that read the 7-segment response, if a screen mode 7-segment display does not respond, the characters the PLC sent are drawn dimmed on the display, and The chip is not responding — the screen is still being sent, but the module may be showing something else. Retrying every second. is shown.
• Box mode 7-segment displays are shown too. However, they are not shown for a program that has two or more FINI with different pins.

MPS-8A8R and MPS-16A8R8T do not read the response from the 7-segment display, so No response is never shown. Instead, This model does not read the chip response (ACK), so a disconnected chip cannot be detected — the screen is re-sent every second. appears below the display.

If there is a problem with a 7-segment cell, the cell turns red (the program cannot be compiled) or its address turns orange (a warning; the program can still be compiled). Hover over the cell to see the reason. When you select the cell, the Inspector shows the same reason.

If a 7-segment screen definition has a problem, it is listed in the problem list at the bottom of the editor, and the FSCR cells that use that table turn red and cannot be compiled. Click a row to go to that display, screen or value field. If there are no problems, No problems is shown.

This example connects a 4-digit module to the FND / ENCO connector of MPS-8A8R(T)-S and shows the value of D0 with two decimal places. On this model, the 7-segment display switches on without FINI.

• FINT D0 4 4 2 TRUE FALSE writes the ones digit of D0 to POS 4 (the rightmost digit), shows 4 digits, puts a dot after the second digit and fills the leading digits with 0.
• In simulation, open the 7-Segment Screen Editor and select the entry under Box mode (FINI, FINT, FDATA) to see 12.34. If you change 1234 in rung 1 to 5, 00.05 is shown.

In this example on MPS-8A8R(T)-S, screen 0 shows the run value D10, screen 1 shows Er with the error code D11, and the display switches to screen 1 when P0 turns on.

1. Open Settings → 7-Segment Screen Editor and click Add 7-segment display (display 1 · 4 digits · screen 0).
2. Screen 0: Click digit 1, click Add value field → Dec, and enter D10 in Address (start digit 1 · width 4).
3. Click ＋ in Screens to make screen 1.
4. Screen 1: Click digit 1 and type Er. Then click digit 3, click Add value field → Dec, set Address to D11 and the width to 2, and turn on Pad with leading zeros.
5. Write the rungs below.

In simulation, the display shows 1234 while P0 is off and Er05 when P0 is on. Instead of rungs 0 and 1, you can also write a single rung, @ON (NO) → FSCR 1 D20, and switch screens with the value of D20 (0 or 1).

• Phase 4 · Functions
• Phase 8 · Simulation
• Phase 7 · Monitoring and the Data Table
• CLCD Screen Editor
• 7-Segment LED Guide

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