E03 Pulse Width

Definition

Sets the pulse width of the flow meter when E02 OCT Definition is set to “Pulse v2”. Default: 0.5 ms.

Pulse Output – Pulse V2 Function (Click to Expand)

一、 Technical Principle: Pulse V2 “Batch Reporting” Mechanism

Pulse V2 differs from traditional continuous variable-frequency pulse output. It uses a periodic pulse burst mechanism. At the end of each update cycle, the system converts the accumulated flow into a burst of pulses and transmits them in a short period of time.

A19 Defines the “Reporting Cycle”:

• A19 = 1.0 s (Default): Flow is accumulated every 1 second, and the corresponding pulse burst is transmitted during the following 1 second.

• A19 = 0.5 s (High-speed): Flow is accumulated every 0.5 seconds, and the corresponding pulse burst is transmitted during the following 0.5 seconds.

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2. Parameter Configuration Table

Parameter Code	Name	Function Description	Setting Recommendation
A19	Fast Update	Flow Calculation Cycle	1.0 s: Suitable for general PLC applications. 0.5 s: Suitable for high-precision or high-speed counting applications.
E02	OCT Definition	Output Mode Selection	Pulse V2 must be selected.
E14	Pulse Base Unit	Flow per Pulse	Determines the resolution (e.g., 0.1 represents 0.1 L/pulse).
E03	Pulse Width	Signal Duration	Determines whether the PLC can correctly capture the signal.

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3. Core Steps: Settings Based on PLC Type

Option A: Connected to General PLC Input (Common DI)

• Applicable for: PLCs without high-speed counting modules or with slow scan cycles (>10 ms).

• A19 (Update Frequency): Recommended 1.0 s (updates once per second).

• E14 (Resolution): Recommended large (e.g., 0.1 or 1.0).

• E03 (Pulse Width): Recommended 50 ms.

• Limitation: When the flow rate is high, the total number of pulses should not be too large, otherwise all pulses may not be transmitted within 1 second.

Option B: Connected to PLC High-Speed Counting Module (HSC)

• Applicable for: Precise quantitative control and high-resolution monitoring.

• A19 (Update Frequency): Can be set to 0.5 s (updates every 0.5 seconds).

• E14 (Resolution): Can be set small (e.g., 0.01 or 0.001).

• E03 (Pulse Width): Recommended 0.5 ms (default) or 1 ms.

• Limitation: Although HSC can read high-frequency signals, it must still ensure that all pulses can be transmitted within 0.5 seconds.

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4. Frequency Safety Check (Error Prevention Calculation)

To prevent signal overlap (“traffic jam”) that may cause the PLC to miss pulses, the following calculation should be performed: verify whether the pulse burst generated at maximum flow can be fully transmitted within the A19 reporting cycle.

1. Calculate the Number of Pulses per Cycle (N)

First, calculate the maximum number of pulses the flowmeter can generate within one update cycle:

$N = \frac{(\mathrm{Maximum\ LPM} / 60) \times \mathrm{A19\ Cycle\ (s)}}{E14}$

2. Determine Safety Standard

To ensure sufficient spacing between pulses (recommended 50% duty cycle), the following condition must be met:

$N×(E03×2)< A19 cycle (s)$

💡 Why multiply by 2?

A complete pulse cycle consists of high-level time (E03) and low-level interval time. To ensure stable detection by the receiving device (PLC), it is generally recommended that the interval time be at least equal to the pulse width.

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Example Scenario Calculation

Assume the following site conditions and settings:

• Maximum Flow: 60 LPM

• A19 (Cycle Time): 1.0 s

• E14 (Pulse Unit): 0.1 L/pulse

• E03 (Pulse Width): 50 ms (0.05 s)

Step 1: Calculate Number of Pulses

$N = \frac{(60 \div 60) \times 1.0}{0.1} = 10 \text{ (pulse)}$

Step 2: Check Safety Standard

$10 \times (0.05 \times 2) = 1.0\text{s}$

Result Evaluation: The calculated transmission time is 1.0 s, exactly equal to the A19 cycle time. This indicates that the signal is at the “limit” state, with almost no extra spacing between pulses. If the actual flow exceeds 60 LPM, pulses may overlap, causing the PLC to miss counts.

Optimization Suggestions:

• Option A: Increase E14 (e.g., set to 0.2) to reduce the number of pulses by half.

• Option B: Decrease E03 (e.g., set to 20 ms) to shorten the duration of each pulse.

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5. Troubleshooting

Q1: The panel shows flow, but the PLC does not receive any values

• Cause A: E03 (Pulse Width) is set too short and is filtered out by the PLC. Solution: Increase E03 to 50 ms.

• Cause B: E02 is not set to Pulse V2.

Q2: PLC misses counts or stops increasing at high flow rates

• Cause: Signal overlap. Pulses are too wide and dense, causing the high-level signal to “stick” and form a straight line. Solution A: Increase E14 (e.g., 0.01 → 0.1) to reduce the total number of pulses. Solution B: Decrease E03 (e.g., 10 ms → 1 ms) to increase spacing between pulses.

Q3: PLC cumulative value does not match the flowmeter panel

• Cause: Pulse frequency approaches the PLC’s sampling limit, causing occasional missed counts.

• Solution: Increase E14 to use a larger pulse unit (e.g., change from 1 mL/pulse to 10 mL/pulse).

Notes

To enable the pulse function, set E02 OCT Definition to “Pulse v2”, configure the pulse width in E03 Pulse Time, set the forward flow unit in B01, and define the pulse output reference unit in E14 Pulse v2 Unit.

Operation Procedure

Button Functions (Click to Expand)

The main unit has four buttons. The bottom line (Line 3) of the LCD displays the current function of each button. Under normal operation, the button functions are as follows:

• Blue Button - Leftmost button: Return, exit, or save settings.

Gray Arrow Buttons:

• Left Gray Button: Page up, increase value, or select item

• Right Gray Button: Page down, decrease value, or select item

• Orange Button: Rightmost button: Enter settings, edit, or confirm selection

Do not hold buttons for extended periods to avoid damage.

Button functions may change depending on the operation context to improve usability or prevent accidental presses.

E03 Pulse Width Setting Steps
• From the main screen (green backlight), 
  press Orange Button (Setup) to enter settings (orange backlight).
• Use Gray Arrow Buttons to select E. Commute , press Orange Button (Enter).
• Use Gray Arrow Buttons to select E03 Pulse Width, press Orange Button (Enter).
• Use Gray Arrow Buttons to choose the options. 
• Press Orange Button (Set) to confirm.
• Press Blue Button (ESC) to return to the main screen (green backlight).

E03 Options, RS485 Values, Read/Write Commands, and Formats

Option	Description	RS-485 Value
0.5 ms (Default)	-	0
1 ms	-	1
10 ms	-	2
50 ms	-	3
100 ms	-	4

Refer to the Read/Write Memory List for the Modbus command format. This parameter uses the Int16 data format.