# 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.
***
### 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. |
***
### 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.
***
### 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.
***
#### 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.
***
### 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
{% hint style="danger" %}
**Do not hold buttons for extended periods to avoid damage.**
{% endhint %}
{% hint style="info" %}
Button functions may change depending on the operation context to improve usability or prevent accidental presses.
{% endhint %}
```
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](https://docs.lorric.com/qr/fu-lt-english-v1/communication/modbus-rtu-protocol/read-write-memory-ram) for the Modbus command format. This parameter uses the Int16 data format.
