OnTimer watchdogs, heartbeats, and EA schedulers

Free education, not signals. This lesson is part of EarnSouthAfrica's free forex course. It does not tell you what to buy or sell, it does not promise income, and it should be practised on a demo account before any real-money decision.

OnTick is tempting because every EA begins there, but not every responsibility belongs there. Some checks should happen even when ticks are quiet. Other checks should happen on a schedule instead of every price update.

This lesson teaches how to think about OnTimer as a system scheduler: heartbeat, risk watchdog, session switch, log rotation, stale data check, calendar refresh, and emergency stop monitor.

What you should be able to do after this lesson

• Use timer events for scheduled EA responsibilities.
• Design heartbeat logs that prove a bot is alive and safe.
• Separate market-tick logic from maintenance, news, spread, and risk checks.

Timer responsibilities

Responsibility	Timer reason
Heartbeat	Proves the EA is running, connected, and reading settings.
Risk watchdog	Checks daily loss, equity drawdown, open exposure, and kill switch state.
Session scheduler	Changes observe-only/no-trade state around sessions, rollover, and news windows.
Data freshness	Detects stale ticks, missing bars, or disconnected terminal state.

OnTick versus OnTimer

• Use OnTick for market updates and signal state that truly depends on fresh prices.
• Use OnTimer for scheduled checks that should not depend on tick frequency.
• Keep timer handlers fast; do not turn a heartbeat into a slow reporting engine.
• Log missed or stale states so the EA can pause instead of pretending everything is normal.

Watchdog drill

Build a demo EA that does not trade. It should print a heartbeat every fixed interval, report connection and account state, block itself during a configured no-trade window, and warn when the latest tick is stale. This teaches operational safety before strategy code enters the picture.

Academy-grade study plan

This is the production-thinking layer of the course. A serious MT5 system is not a lucky Expert Advisor; it is a documented machine with account preflight, symbol preflight, event handling, risk gates, order checks, logs, recovery rules, and demo evidence for every assumption.

Course element	What you must produce
Primary artifact	EA systems engineering dossier
Lesson focus	OnTimer watchdogs, heartbeats, and EA schedulers
Working environment	Demo account, notebook, exported platform data, or local code sandbox. Never live funds for first practice.
Completion standard	You can explain the concept, reproduce the exercise, identify failure modes, and show evidence without relying on a seller's claims.

Instructor workflow

Use this workflow as if an instructor were marking the lesson. The important question is not whether the topic sounds familiar. The question is whether your notes, screenshots, calculations, logs, or code prove that you can apply ontimer watchdogs, heartbeats, and ea schedulers under controlled conditions.

• Start every system session by recording account mode, margin mode, symbol specification, trade permissions, spread state, stops level, freeze level, and session/news context.
• Separate signal logic, position sizing, preflight checks, order submission, trade lifecycle tracking, recovery, and observability so failures can be isolated.
• Use MT5 and MQL5 events deliberately: OnTick for market updates, OnTimer for scheduled checks, OnTradeTransaction for lifecycle evidence, and OnBookEvent only when market-book data is subscribed and useful.
• Treat every reject, retcode, skipped trade, stale quote, bad tick, and risk block as useful evidence rather than an annoyance.

Worked case study: The EA refuses to trade for the right reason

A learner runs a demo EA during a volatile session. The signal is true, but the symbol has a widened spread, the requested stop is inside the broker's stop level, and margin would be too tight after the order. A weak bot sends the trade and blames the broker. A professional system logs each preflight result, rejects the order before submission, and records the account state for review.

After reading the scenario, write the decision you would make before checking the suggested workflow above. Then compare your decision with the operating model. The gap between those two answers is the part of the lesson that deserves another demo repetition.

Professional template

Complete this template in your own notebook. A paid course would normally hide this kind of operating document behind worksheets; here it is part of the free lesson.

Field	Standard
Preflight area	Account mode, symbol specification, margin, stops/freeze level, spread, session, and permission state.
Event handler	OnTick, OnTimer, OnTradeTransaction, OnBookEvent, OnCalculate, or OnTester responsibility.
Safety gate	The exact condition that blocks duplicated, oversized, stale, unfillable, or undocumented trades.
Evidence	Journal/Experts log, tester report, exported settings, screenshots, retcode notes, and review memo.

Failure-mode lab

Paid courses often sell confidence. A serious course teaches you how the idea breaks. Before continuing, test the failure modes below on demo, paper, or code review. If you cannot describe the failure, you are not ready to trust the concept.

• Sending orders before checking broker symbol rules, account mode, filling policy, margin, and stop-distance constraints.
• Using OnTick for every responsibility until the EA becomes impossible to debug.
• Ignoring trade-server retcodes, partial fills, rejects, and asynchronous lifecycle events.
• Optimizing parameters while the underlying execution and risk engine is still unproven.

Evidence pack and pass standard

Do not mark this lesson complete because you read it. Mark it complete only when you can show the evidence below. Keep the files in a dated folder so your learning history survives platform updates, memory gaps, and sales pressure.

• A one-page note explaining ontimer watchdogs, heartbeats, and ea schedulers without sales language or copied definitions.
• A screenshot, export, calculation, log, or code file that proves the practical work was completed on demo.
• A written stop rule that says when this topic must not be used with real money.
• A system preflight table showing pass/fail results for at least three symbols on demo.
• A log excerpt where the system rejects a tempting but unsafe trade with a clear reason.

Assessment rubric

Level	What it looks like
Not ready	You can repeat the vocabulary but cannot complete the demo task, calculate the risk, explain the failure mode, or show evidence.
Course pass	You can complete the practical task on demo, explain the decision rules, show evidence, and name the conditions where the idea must not be used.
Strong pass	You can teach the concept to someone else, find edge cases, document a rejected example, and improve the template without weakening risk controls.

Advanced homework

• Create five deliberately bad trade requests and document exactly where each one should be rejected.
• Build a state diagram for order request, check, send, fill, modification, close, reject, and recovery paths.
• Run the same EA on a demo hedging account and a demo netting account, then document lifecycle differences.

Practical drill

Do this lesson as a controlled exercise, not as a reason to trade live. Open a demo account or notebook, write the lesson title, and record what you changed, clicked, calculated, or checked. If the lesson includes code, compile it only in a demo environment and keep the original version unchanged so you can compare edits safely.

• Write a one-paragraph explanation of ontimer watchdogs, heartbeats, and ea schedulers in your own words.
• Take one screenshot or note that proves you completed the platform, maths, research, or code task.
• Record one risk rule that would stop you from using this idea with real money.
• If anything feels unclear, repeat the lesson before moving to the next module.

How scammers misuse this topic

Scammers often take real concepts and wrap them in urgency. They may use platform jargon, bot screenshots, copied profit charts, or official-sounding language to make a paid offer feel safe. A real concept is not the same as a safe offer. Before paying anyone, ask whether you can verify the provider, reproduce the calculation, test the claim on demo, understand the risk, and walk away without pressure.

Checkpoint before continuing

• You can decide which checks belong in OnTick and which belong in OnTimer.
• Your EA has a heartbeat that confirms running, paused, blocked, and error states.
• Your scheduler can put the EA into observe-only mode without deleting it from the chart.

Official references

These lessons are written as free education. When platform features or rules matter, verify against the official source before using real money.

• MQL5 EventSetTimer documentation
• MQL5 event handlers
• MetaTrader 5 terminal help

Risk note: leveraged forex and contracts for difference can lose money quickly. EarnSouthAfrica is an educational publisher, not a broker, adviser, signal provider, or money manager.