I. Overview
The HP-DY-8 voltage monitor is a specialized instrument developed in strict accordance with the Ministry of Power's DL500—92 "Technical Conditions for Voltage Monitor Ordering," utilizing a high-speed MCS—51 series chip as the processor. Data transmission is via RS485. It is suitable for the scientific management of voltage monitoring in power supply systems.

II. Key Features:
1. Display Format: LED LCD Display
2. Sampling Cycle: 250ms
3. Display Cycle: 1s
4. Statistical Period: 1 min
5. Statistical Object

The system can collect, display, and categorize signals from high-voltage power grids of 3KV or above, with voltages ranging from PT to 57.7V-100V, as well as 220V and 380V voltages.

6. Statistical Form

The instruments are automatically categorized and statistically analyzed by time, day, and month.

Section 3: Key Monitoring Functions
1、Monthly Statistics
The unit stores monthly statistical data for 12 months, displaying the total operating time, qualified time, qualification rate, rate of exceeding the upper limit and the time of exceeding the upper limit, rate of exceeding the lower limit and the time of exceeding the lower limit, high voltage values and the moments of high voltage occurrence, and low voltage values and the moments of low voltage occurrence for the current month and the previous month.

2. Daily statistics of the local storage for the past 2 months, displaying the total operating time, qualified time, pass rate, over-limit rate and over-limit time, under-limit rate and under-limit time, high voltage values and their occurrence times, and low voltage values and their occurrence times for the current and previous days.

3. On-the-hour Statistics

This unit provides the whole-hour statistics for the most recent and current month.

4. Power Outage Record

The unit provides the number of power outages and the duration of each outage.

5. Individual alarm upper and lower limits can be set. An alarm output is generated when the instantaneous pressure value exceeds the alarm upper and lower limits.

6. Features manual adjustment for measurement values.

7. Features a "watchdog" function to ensure reliable program operation.

8. Enter parameter settings, featuring prevention of abnormal operations.

IV. Main Technical Specifications
1. Measurement Range: Un + 20% (Un being the voltage grade to be measured)
2. Measurement Accuracy: ≤0.5%
3. Timing Accuracy: ≤+0.5 seconds/day
4. Statistical Accuracy: ≤0.5%
5. Resolution:       ≤0.01%
6. Signal Input Circuit Power Consumption: ≤0.6VA
7. Power circuit power consumption:   ≤2VA
8. Insulation Resistance ≥ 500 Megohms
9. Working Frequency Insulation Strength: 1.5KV, non-penetrated in 1 minute
10. The E2PROM stores critical data with a shelf life of 100 years.

11. Communication Medium RS485

12. Standard Operating Environment

13. Environmental Temperature:-40℃～+70℃

14. Relative Humidity:+45°C at 90%

Atmospheric Pressure: 79.5～106.0 kPa (up to 2000m altitude).

16. Power Supply: Tested Power Supply and Auxiliary Power Supply.

Installation Method: Flush-mounted.

18. Collection Loop: Three-Phase.