What Is the Primary Hours Only Setting in Job Totals?
User Solutions TeamPrimary Hours Only is the job-level hours option that counts primary steps only when totaling hours, excluding the mirrored steps that synchronized parallel machines produce, so a job's total reads the work elapsed rather than the machine time consumed. Three mirrored drill heads log twenty-four machine-hours between them; with this setting on, the job total reads eight.
EDGEBIC by User Solutions exposes it on the Schedule page of Settings, under Job-Level Hours, where it is off by default. This article defines which hours it excludes and why both totals are correct. For the arrangement that creates the duplication, see the sibling term dependent parallel processing.
How It Works
When an operation runs on several machines that must work simultaneously, EDGEBIC models it as a primary step plus one mirrored step per additional machine. Each mirrored step holds the same window as the primary and its own hours, because each machine really is occupied for that window and that time is genuinely unavailable to anything else.
That produces two different, equally true answers to the question of how many hours a job represents:
- All hours. The sum across primary and mirrored steps. This is machine time consumed. Three heads working eight hours is twenty-four hours of machine capacity.
- Primary hours only. The sum across primary steps alone. This is work elapsed. The same operation reads eight hours.
The setting chooses which of the two your totals show. It is a rollup rule, so it takes effect immediately on the screens it affects rather than waiting for a scheduler run, and it changes nothing about the plan itself: the same operations run at the same times on the same machines, and each machine's own load and utilization are unaffected.
Because it applies everywhere hours roll up, a job's total reads the same number in the routing header, in Job View, and in reports. There is no per-screen version, which is deliberate: two different totals for one job is worse than either total on its own.
A Concrete Example
Think of three painters and one wall. The wall takes two hours with all three working. The job took two hours; it also took six painter-hours. Ask the foreman how long the wall took and you get two. Ask the accountant what it cost and you get six. Neither is wrong, and quoting the wrong one in the wrong meeting causes an argument.
At Acme Industries, Weld-1 runs three synchronized drill heads on Bracket-B:
| Step | Kind | Hours held |
|---|---|---|
| Weld-1 head 1 | primary | 8.0 |
| Weld-1 head 2 | mirrored | 8.0 |
| Weld-1 head 3 | mirrored | 8.0 |
| Setting | Job total for this operation |
|---|---|
| Off, the default | 24.0 hours |
| On | 8.0 hours |
The floor reports eight, because that is what the shift experienced. With the setting off, the job total says twenty-four and the two numbers appear to disagree.
How EDGEBIC Uses It
The default is off because machine time is the more conservative figure and because most sites do not run synchronized parallel operations at all. Where there are none, the setting makes no difference: every step is a primary step and both totals are identical.
Where synchronized parallel operations do exist, the choice is really about who reads the number. A planner comparing job totals against what supervisors report from the floor wants elapsed work, and should turn the setting on. Someone costing machine time, or judging how much equipment a job ties up, wants the full figure and should leave it off.
The signature that prompts most sites to look at it is a job total that is an exact multiple of what the floor reports, matching the number of machines on a synchronized operation. That multiple is the arithmetic of mirroring, not a data error, and it resolves with one tick.
Two things are worth knowing when you flip it. It is safe, because it touches totals and not the plan or the capacity picture. And it is visible, because a job total that drops from twenty-four to eight looks alarming to anyone who was not told, and figures recorded before the change will not reconcile with figures taken after it.
For how the mirrored steps arise, see what is a parallel work center type, and for how their actuals behave see what is parallel actuals mirroring in scheduling. For the comparison the totals feed, see what is planned vs actual hours. Browse more definitions in the manufacturing glossary.
It is a job-level hours option that makes job and routing hour totals count primary steps only, excluding the mirrored steps created by synchronized parallel machines. Three mirrored drill heads log twenty-four machine-hours between them, but with the setting on the job total reads eight, the elapsed work rather than the machine time. It is off by default.
No. It is a display and rollup setting only. The plan, the capacity consumed on each machine, and the dates are all unchanged, and it takes effect immediately on the screens it affects rather than waiting for a scheduler run. It only alters which hours are summed into a total.
Everywhere hours roll up: routing header totals, Job View, and reports. It is deliberately a single setting rather than a per-screen toggle, so a job's total hours read the same number wherever you look at them and nobody has to reconcile two different figures for the same job.
Almost certainly not, and the multiple is the clue. A factor of exactly three on a job that runs a synchronized three-machine operation is the signature of mirrored parallel hours being counted in the total. When several machines are synchronized on one operation, each one holds its own hours for the window, because each machine really is occupied for that time. Summed naively, an eight-hour operation on three heads contributes twenty-four hours to the job. Both numbers are true, they just answer different questions: twenty-four is the machine time consumed, eight is the work elapsed. The floor reports the second because that is what an operator experiences. Ticking Primary Hours Only makes the job total report the second as well. Before you do, check that the multiple matches your parallel configuration, because if it does not, the cause may be something else and worth finding.
No, because capacity is not calculated from these totals. The setting changes what gets summed into a job or routing header figure; it does not change what each machine has booked. A work center that is occupied for eight hours by a mirrored operation is still shown as occupied for eight hours in its own load and utilization, because that time is genuinely unavailable for other work. What changes is only the job-level answer to how many hours this job represents. This is why the setting is safe to flip and why it takes effect immediately rather than on the next scheduler run. The one thing to do when you turn it on is tell whoever reads the reports, because a job total that drops from twenty-four to eight overnight looks alarming if nobody knows why, and any figure someone recorded from before the change will not reconcile with figures taken after it.
Expert Q&A: Deep Dive
Q: Our job totals read three times what the floor reports for a welding job. Is something wrong with our data?
A: Almost certainly not, and the multiple is the clue. A factor of exactly three on a job that runs a synchronized three-machine operation is the signature of mirrored parallel hours being counted in the total. When several machines are synchronized on one operation, each one holds its own hours for the window, because each machine really is occupied for that time. Summed naively, an eight-hour operation on three heads contributes twenty-four hours to the job. Both numbers are true, they just answer different questions: twenty-four is the machine time consumed, eight is the work elapsed. The floor reports the second because that is what an operator experiences. Ticking Primary Hours Only makes the job total report the second as well. Before you do, check that the multiple matches your parallel configuration, because if it does not, the cause may be something else and worth finding.
Q: If we turn Primary Hours Only on, does our capacity picture become wrong?
A: No, because capacity is not calculated from these totals. The setting changes what gets summed into a job or routing header figure; it does not change what each machine has booked. A work center that is occupied for eight hours by a mirrored operation is still shown as occupied for eight hours in its own load and utilization, because that time is genuinely unavailable for other work. What changes is only the job-level answer to how many hours this job represents. This is why the setting is safe to flip and why it takes effect immediately rather than on the next scheduler run. The one thing to do when you turn it on is tell whoever reads the reports, because a job total that drops from twenty-four to eight overnight looks alarming if nobody knows why, and any figure someone recorded from before the change will not reconcile with figures taken after it.
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