Display HH:MM:SS time on an HMI numeric object

Why the separator list has no colon

A numeric object shows a whole part, a separator mark and fractional digits. The digits are a base-10 fraction, so the mark is a decimal point, and the property list offers its two spellings: a period or a comma. Open the object's properties and read the list. If it holds a period and a comma and nothing else, the object has no colon to give you, and time fields count in base 60 anyway: minutes run 0 to 59 and seconds run 0 to 59, so a decimal fraction cannot carry them.

That mismatch is what sinks the usual workarounds.

What you need

• The time in the PLC in one of two forms: three integer registers (hours, minutes, seconds) or one elapsed-seconds count.
• For a single count, three integer destinations for the split result.
• HMI programming software with a message database, or any text object that accepts embedded variables.
• A message or text display object on the screen.
• A download path to the panel for the test.

If you have never placed a variable inside message text, your HMI editor's manual for its message database or text object covers the mechanics; the only extra step here is typing the colons as literal characters between the three tags.

Sort the source data first

Monitor the registers in the PLC, not on the panel, and note which of three forms the time takes.

1. Three separate integers, one each for hours, minutes and seconds: skip the split and go straight to the message build.
2. One elapsed-seconds count from a timer or counter accumulator: do the split in the PLC before anything reaches the screen.
3. A decimal such as 12.34 standing in for 12:34: move the two parts into separate integer registers first. A base-10 decimal cannot carry base-60 fields, and no formatting on the display side repairs the digits.

There is one shortcut. If the screen only has to show the panel's current wall time, the clock object already does it and no registers are involved. For a date with a 12-hour clock on one line, your package's clock and text objects carry the same embedded-field mechanics described below.

Split total seconds in the PLC

In words: integer-divide the total by 3600 to get hours. The remainder of that divide holds everything under one hour; integer-divide it by 60 to get minutes, and what is left is seconds. Integer divide truncates, which is what a clock does with a partial hour and a partial minute.

The same split sits behind a rolling 24 hour runtime for a pump display, where the counter also accumulates whole seconds, so build the accumulation once and reuse it.

The names and types below are illustrative. Use your platform's integer divide and remainder instructions and keep the destinations integer-typed, so each divide truncates.

TotalSec : DINT := 3725;   (* whole seconds from the timer accumulator *)
Hours    : DINT := 0;
Minutes  : DINT := 0;
Seconds  : DINT := 0;

Hours   := TotalSec / 3600;           (* integer divide *)
Minutes := (TotalSec MOD 3600) / 60;  (* integer divide *)
Seconds := TotalSec MOD 60;           (* remainder *)

In ladder the same three results come from the divide instruction and the remainder instruction with the constants 3600 and 60.

If the count arrives as two 16-bit words that form a 32-bit value, confirm the word order before the split. A swapped pair produces a huge but plausible hours count, and nothing on the screen looks obviously broken.

Worked example: a batch timer at 3725 seconds

Inputs: TotalSec = 3725 s, one 32-bit integer in the PLC that a batch cycle timer increments once per second. The divisors are fixed: 3600 s per hour and 60 s per minute. The variable name is illustrative; the case is any elapsed-seconds count, and this value is a typical batch time.

Rule: hours are TotalSec divided by 3600 with the remainder kept; minutes are that remainder divided by 60 with the remainder kept; seconds are the final remainder.

Arithmetic:

• Hours: 3725 ÷ 3600 = 1 remainder 125 (1 × 3600 = 3600; 3725 − 3600 = 125).
• Minutes: 125 ÷ 60 = 2 remainder 5 (2 × 60 = 120; 125 − 120 = 5).
• Seconds: 5.

Result: 1 h, 2 min, 5 s, printed as two digits each, so the message reads 01:02:05.

Decision: force the accumulator to 3725 and the screen must show 01:02:05. Two-digit hours carry every total up to 359999 s, which prints 99:59:59. The next second, 360000 s, needs a third hour digit, so widen the hours field when you build the message or reset the counter at the end of each shift.

Build the HH:MM:SS message

1. Create three integer tags in the panel tag database, one for each register the split writes, or for the three original registers.
2. Add a new message in the message database.
3. Insert the hours tag as an embedded data value, type :, insert the minutes tag, type :, then insert the seconds tag. The layout reads HOUR:MINUTE:SECOND.
4. Set each embedded field to two digits with leading-zero fill, so a raw 5 prints 05.
5. Place the message display object on the screen and assign the new message to it. Size the object for the widest string you expect, eight characters for HH:MM:SS.
6. Download the project to the panel and run the checks below.

Recommendation: Drive one message entry with three embedded integer tags whenever the time comes from a register, a timer or an elapsed count, and split the count in the PLC first so each tag carries a whole number. Keep the three-numeric-object layout only as a temporary restore that runs the line before the message is built, and reach for the clock object only when the screen needs the panel's current wall time.

Check it against known values

Force the source register, or all three registers, to the values in the table and read the screen. The expected strings come straight from the split.

59 s is the last second with no full minute, 60 s is the first minute carry, 3599 s is the last second with zero hours and 3600 s is the first hour carry. If a row disagrees, the split is wrong, not the message. When all six agree, let the value count live and watch the seconds roll into minutes with the string width unchanged.

Pitfalls once it runs

• Leading zeros missing. 1:2:5 on the screen means the embedded fields print raw values; set two digits with leading-zero fill on all three fields.
• Hours outgrow the object. Past the two-digit hour ceiling the hour field needs a third digit; widen the message and the object together.
• A signed register crosses zero. A countdown through zero prints a minus sign and shifts every field. Clamp the total at zero in the PLC or format it as time remaining.
• The tag points at a register the PLC stopped writing. Watch the register in the PLC and the object on the panel at the same time. A register that moves with a still screen means the tag address is wrong; repoint it.

If you also want a separate shop-floor notice or status screen next to the machine, our industrial displays for shop-floor signage are built for that job.

Questions