Servicing of the Remote Monitoring Unit at Bukit Gombak Camp
Image of Remote Monitoring Unit
Overview of Project
The remote monitoring unit (RMU) is a remote alarm warning system that utilizes GSM technology to alert and inform users whenever an alarm or sensor is triggered through SMS notifications. It can receive both digital and analogue inputs, which are the 2 main inputs the remote monitoring unit can accept. Furthermore, each SMS notification can be customized based on the needs of the user.
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When an alarm or sensor is connected to the analogue input, the current voltage will exceed the trip voltage whenever an alarm or sensor is activated. As a result, the RMU would send the user an SMS notification to inform them of the fault. For digital inputs, the logic level would switch from "LOW (0V)" to "HIGH (5V)" whenever an alarm or sensor was triggered. As such, the RMU would send an SMS warning to the user if the logic level at the digital input pins is "HIGH."
Image of Remote Monitoring Unit at Bukit Gombak Camp Pump House
It is usually installed in areas with a large number of alarms and sensors such as pump houses and sever rooms. Furthermore, because the maintenance engineers would no longer have to constantly monitor the pumps, their workload would be decreased, and the extra manpower could be better allocated to other tasks. Furthermore, the pump rooms are extremely hot and humid, making it difficult for employees to work there for extended periods of time.
My Roles and Responsibilities
My role in this project is to assist Ace to service the RMU at the Bukit Gombak Camp (MINDEF HQ) pump house. I'm also in charge of conducting a routine check of the RMU in the server room at Gombak Camp BLK 307.
My Contributions
I helped to test the RMU at the pump house using the various skills imparted to me by my colleague and I was able to successfully test the RMU. Furthermore, I helped to set the phone numbers of the maintenance engineers into the RMU. Lastly, I also helped to configure the different analogue and digital inputs of the RMU to their desired specifications (e.g., content of warning SMS, trip voltage).
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I also helped to perform the routine check at the server room at Gombak Camp BLK 307. I carried out the necessary procedures, which included deleting all the contact information kept in the remote monitoring unit and replacing it with the point of contact's contact number because we did not want to raise any false alarms. Furthermore, I also needed to conduct the transmission check, routine check and the power failure check.
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Before the RMU can be deemed to be in good working order, it must pass the transmission test, routine check, point-to-point check, and power failure test. Furthermore, I also learned how to test and service the RMU by shorting 5V to the various pins using a jumper wire and verifying that a warning SMS is received.​
Explanation of the various tests that must be performed on the RMU
The transmission is a simple check to verify the functionality of the SIM Card and antenna before we perform the other checks, it can be triggered by pressing the “down” button four times on the monitoring page. It will then transmit an SMS notification to a pre-set phone number and the pre-set phone number can be changed using the buttons on the RMU. Alternatively, we can also set the phone number using the RMU PCLink software.
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As part of its routine check, the RMU will send out a periodic SMS notification. The objective of the routine check is to ensure that the RMU is operating normally on a daily basis. By accessing the unit details page in the RMU, the interval between each routine notification can be adjusted.
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The point-to-point check ensures that all of the RMU's analogue and digital input pins, each of which corresponds to a pump's alarm, are functioning properly. When there is a fault with the pump, the voltage at the pin will be "HIGH (~5V)" and the RMU will send a warning SMS notification indicating that there is a fault with the specific pump.
When the issue is resolved, the voltage at the pin will be "LOW (~0V)" and the RMU will send another SMS notification indicating that the issue with the pump has been resolved. When compared to the digital input pins, the analogue input pins work in the same way. However, the voltage at which the warning SMS notification is transmitted is dependent on the trip voltage.
The trip voltage determines the minimum voltage before the warning SMS is sent and it can be adjusted using the RMU interface. The RMU interface can also be used to modify the contents of the SMS notification. Furthermore, we can set whether the warning SMS is sent when the voltage at the pin is "HIGH (~5V)" or "LOW (~0V)".
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The power failure test simulates a power outage whenever the AC power is disconnected from the remote monitoring unit, and it will notify the user of a power outage whenever it occurs by sending out a warning notification using its internal batteries. As such, the power failure test ensures that the RMU can continue to operate on its internal battery and verifies that it is able to send a warning SMS notification to warn the maintenance engineers about the power outage.
Real world application of industry domain knowledge and skills in the workplace
In both Digital Fundamentals and Applied Digital Electronics, we learned the fundamentals of digital electronics, and I was able to apply the theoretical knowledge I gained from my lecturers in both modules to understand how we can use two different voltages, "High (~5V)" and "Low (~0V), to generate two different distinct outputs. As a result, I was able to quickly understand how the RMU operates.
Learning points
I learned how to navigate the RMU using the buttons on it as well as how to use the RMU PCLink software to reprogram the RMU.
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I also realized the importance of servicing the RMU every three months to ensure that it functions properly.
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In addition, I learned how to service and test the Remote Monitoring unit by conducting the transmission test, routine check, point-to-point check, and the power failure test before it can be deemed to be in good working condition.