Y921 — RS485 Cloud Data Logger Specification

Contents

1. Overview
2. Standard Models and Configuration
3. YenGear IoT Cloud
4. Data Path and Operating Boundary
5. Selection and Ordering
6. Installation Requirements
7. Contact

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1. Overview

Y921 provides four RS485 interfaces and uses Modbus RTU to collect operating data from sensors, meters, controllers, and other field devices. Y921-G, Y921-W, and Y921-R connect through 4G, Wi-Fi, and RJ45 Ethernet, respectively. The standard product connects to YenGear IoT Cloud; third-party platform integration is available as a project customization.

Y921 collects and reports data. It does not control field devices. Real-time collection depends on the network connection. During a network interruption, Y921 does not create collection records, cache data, or backfill the interrupted period. After the network returns, the device reconnects automatically and resumes real-time collection.

Compatible Field Devices

• Temperature, humidity, level, pressure, water-quality, and other sensors using RS485 Modbus RTU
• Electricity meters, flow meters, and other instruments using RS485 Modbus RTU
• PLCs, controllers, and field equipment whose operating status or measurements can be read through RS485 Modbus RTU

Standard Y921 models do not accept analog signals directly. Use a customized Y921 or a suitable signal converter when the project requires analog acquisition.

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2. Standard Models and Configuration

Select Y921-G, Y921-W, or Y921-R from the available site network. Each standard model provides one uplink network.

Model	Uplink Network	Typical Site Condition
Y921-G	4G	No stable wired network or Wi-Fi at the site
Y921-W	Wi-Fi	Stable wireless LAN is available
Y921-R	RJ45 Ethernet	Stable wired Ethernet is available

A project that requires two or more uplink networks needs a customized combined-network configuration.

Standard Configuration

Item	Standard Specification
Collection interfaces	4 × RS485
Field protocol	Modbus RTU
Uplink network	One of 4G, Wi-Fi, or RJ45 Ethernet, selected by model
Primary functions	Data collection and status reporting
Operating mode	Online real-time collection
Network interruption	No collection, cache, or backfill during the interruption
Recovery	Reconnects and resumes real-time collection after the network returns

Project Customization

Item	Customization Scope
Collection interface	RS232
Signal acquisition	Analog signals
Uplink network	Combined networks
Field protocol	Serial protocols other than Modbus RTU
Platform	Third-party platform integration

Customization depends on the required interfaces, signals, protocols, network, and integration tests.

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3. YenGear IoT Cloud

Users configure collection points and Modbus parameters in YenGear IoT Cloud, including slave address, register address, data format, byte order, scaling factor, and collection interval.

The platform displays real-time data, stores historical records, and processes alarms according to the configured collection points. Y921 reads and uploads the field data.

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4. Data Path and Operating Boundary

RS485 sensors, meters, or controllers
                 ↓
               Y921
                 ↓
       4G / Wi-Fi / Ethernet
                 ↓
         YenGear IoT Cloud
                 ↓
   Real-time data / history / alarms

Y921 reads and reports field data only. Use a product with verified control outputs when a project must start, stop, or otherwise control pumps, fans, lighting, or other loads.

Network loss affects the collection path itself, not only cloud display. The device produces no records for the disconnected interval and does not upload missing historical data after reconnection.

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5. Selection and Ordering

Selection Steps

1. Confirm that the field equipment uses RS485 Modbus RTU, or provide the required interface and protocol customization.
2. Select Y921-G, Y921-W, or Y921-R from the site network.
3. Provide the field-device manuals, Modbus register maps, and communication parameters.
4. Confirm site power, mounting, wiring, antenna, and Ethernet-cable conditions.

Information Required Before Ordering

Item	Required Information
Standard model	Y921-G, Y921-W, or Y921-R
Field devices	Name, quantity, model, and product manual
RS485 settings	Slave address, baud rate, parity, and register map
Collection points	Data items, units, and required collection interval
Customization	RS232, analog signals, combined networks, other serial protocols, or third-party platform integration
Site conditions	Power, installation space, network coverage, and cable routing

The supported device count and collection-point count depend on baud rate, register count, collection interval, and field communication quality. Confirm them from the actual point list before ordering.

Power input, operating temperature, dimensions, mounting, interface protection, and accessories depend on the communication version and enclosure configuration. Confirm these parameters for the selected configuration.

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6. Installation Requirements

1. Install the device where wiring, inspection, and maintenance remain accessible.
2. Connect RS485 A/B lines according to the field-device manual and verify polarity.
3. Assign a unique address to each device on the same bus and use consistent communication settings.
4. Keep Y921-G and Y921-W away from strong interference and large metal obstructions.
5. Use Ethernet cabling and network equipment suitable for the site with Y921-R.

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7. Contact

Contact YenGear for selection or customization requirements.

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• Manufacturer: Hunan YenGear Tech Co., Ltd.
• Address: Room 21014, Building 1, Fudi Xingguang Tiandi, Yingxin Road, Yuhua District, Changsha, Hunan, China
• Email: hi@yengear.com
• Website: www.yengear.com