Multi-Drop Transmitter Startup Control via Staggered Sequencing
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Solution Overview
Problem
In industrial processing facilities, process variable transmitters in multi-drop network configurations face startup current issues due to most power supplies being unable to supply the required high initial current levels, leading to potential startup failures and downtime.
Innovation Solution
Implementing a power accumulator module with an energy storage device, such as capacitors or rechargeable batteries, and a startup sequencing algorithm that monitors initial node voltage and sets a pseudo-random low power state time for each transmitter, ensuring staggered startup and preventing current starvation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple process variable transmitters are connected in parallel on a common line to share loop current from a common DC power supply, then the quantity of field devices on the network is increased, but the power supply becomes unable to provide sufficient startup current to all devices simultaneously
Solution Approach 1:
The startup sequencing algorithm performs preliminary actions by monitoring initial node voltage and implementing a pseudo-random low power state time for each transmitter. This staggered startup approach prevents simultaneous high current demands, allowing multiple field devices to be connected while maintaining power supply capability.
2Reliability
If the power supply provides high initial current levels to all transmitters simultaneously at startup, then all transmitters can initialize properly, but the power supply becomes overloaded and current starvation occurs
Solution Approach 1:
The startup sequencing algorithm implements periodic action through time-based current distribution. Each transmitter is assigned a pseudo-random low power state time, creating a staggered startup sequence where transmitters initialize at different times rather than simultaneously, preventing current starvation while maintaining startup reliability.
3Power
If a fixed startup delay is applied to all transmitters, then current overload is prevented, but startup time becomes deterministic and potential conflicts remain
Solution Approach 1:
The startup sequencing algorithm applies asymmetry by using pseudo-random low power state times for different transmitters rather than uniform fixed delays. This asymmetric approach maintains current distribution control while reducing the likelihood of synchronized startup conflicts, and the pseudo-random nature introduces variability to prevent systematic timing issues.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows process variable transmitters to start up successfully without overloading the power supply, preventing failures and minimizing downtime by managing current distribution and sequencing start-ups.
Implementation Method 1
an energy storage device (e.g., a capacitor)
Implementation Method 2
a power accumulator module comprising an energy storage device
Implementation Method 3
or a rechargeable battery
Data Source
AI summary
A method of operating process variable transmitters configured for sensing within an industrial processing facility connected in parallel to a current loop that receives power from a common power supply. The transmitters include a power accumulator module including an energy storage device including at least one capacitor or a rechargeable battery and a sensor module including a transceiver coupled to a processor having an associated memory that stores a startup sequencing algorithm. After a fixed period of time following a startup, an initial node voltage is measured across the energy storage device. The initial node voltage is compared to a predetermined voltage, and the transmitter is placed in a low power mode when the initial node voltage is <the predetermined voltage, an at least partially random low power state time for the transmitter is set, and startup sequencing algorithm is restarted after the low power time.