The Hitelecom HD20-4000 series combines field data acquisition, equipment monitoring and control in a compact RTU. The 4DO + 4DI + 4AI reference configuration connects digital equipment states, external analogue measurements and compatible control circuits. Edge processing, local, remote and condition-based control, and remote configuration and firmware upgrades support the installation throughout its operating life. View uploaded monitoring data online in Hitelecom Cloud and receive alerts when configured thresholds are exceeded.
KEY FEATURES
Connect four reference digital outputs, four digital inputs and four analogue inputs to a defined equipment workflow, with online monitoring and configured threshold alerts in Hitelecom Cloud.
The 4DO + 4DI + 4AI reference configuration combines four control outputs, four equipment-state inputs and four analogue measurement inputs. Build the point allocation around the actual instrument and equipment signal list.
Process field information close to its source for equipment monitoring and condition-based actions. The project configuration defines the signal interpretation, control conditions and permitted responses.
Use the operating mode that fits the task: local operation, remote supervision or an action linked to a configured condition. Define priorities and equipment feedback for the selected control arrangement.
Support project-defined device coordination with master/slave working modes. The selected interface, communication protocol and device roles form part of the integration configuration.
Use Hitelecom Cloud to view uploaded monitoring data online and receive alerts when configured thresholds are exceeded. Map equipment states, measurement units and alert recipients to the operating workflow.
Adjust supported settings and upgrade device firmware remotely. Plan maintenance around the installed configuration, software version and the site’s operating procedure.
Dual watchdog mechanisms support recovery from defined software or system faults. Recovery behaviour and output states are part of the device configuration and commissioning checks.
Bring monitoring and control into equipment rooms, service cabinets and distributed installations with a compact controller design. Select the power, enclosure and wiring arrangement for the site.
FIELD INTERFACES
The reference configuration provides 4 digital outputs, 4 digital inputs and 4 analogue inputs. Select electrical compatibility, output circuits and point allocation for the supplied version.
Issue defined control commands through four digital outputs in the reference configuration. Select the output electrical type and connect each point to a compatible equipment control circuit.
Acquire four equipment-state signals in the reference configuration. Define the electrical compatibility, normal state and operating meaning of each digital input.
Acquire four analogue measurement signals in the reference configuration. Match each external transmitter to the supplied input range, engineering units and scaling.
MONITORING & CONTROL
Combine data acquisition with local, remote and condition-based control. Verify the equipment state separately from the requested output action.
Connect equipment-state signals and compatible analogue transmitter outputs. Give each point an asset identity, signal definition, engineering range and normal state.
Select local, remote or condition-based operation for each permitted action. Specify the initiating condition, command priority and equipment response required by the project.
Send defined digital commands through electrically compatible control interfaces. The host equipment retains its sequencing, interlocks and independent protection functions.
Check available equipment feedback independently of the output command. View uploaded states and measurements in Hitelecom Cloud and verify configured threshold alerts during commissioning.
APPLICATIONS
Eight application areas, with five engineering tasks in each, show how the controller can connect monitoring points and permitted control actions. These 40 tasks are selection examples, not 40 simultaneous channels or a claim that every task is fitted in one device. Allocate the selected signals against the 4DI / 4AI / 4DO reference configuration; larger point lists may require another configuration or additional controllers. External instruments, communication interfaces and load-control equipment are selected for the project.
8 application areas / 40 project tasks
Representative environments. Field instruments and control circuits are selected for each installation.
Connect selected machine states, external measurements and auxiliary control circuits for service visibility across unattended retail equipment. Define the interface with the machine supplier; dispensing sequences, payment and transaction processing remain with their dedicated systems.
Read available ready, running or fault signals to distinguish a machine that is available for service from one requiring inspection.
Collect external temperature-transmitter signals from selected compartments to support cold-storage condition monitoring.
Identify service-door openings and maintenance-mode states under the correct machine asset.
Combine a selected leakage event with available drainage-equipment feedback to support service response inside a vending installation.
Add defined local or remote requests for machine lighting or a service-status indicator through compatible auxiliary circuits.
Bring selected shelf-equipment states and external measurements into retail operations monitoring. Interface selection is project-specific; this does not imply native compatibility with electronic price-label networks or inventory software.
Monitor compatible ready and fault outputs from an electronic shelf controller or powered retail fixture.
Associate selected external temperature or humidity measurements with a defined shelf zone or retail display area.
Identify selected alarm states from a shelf rail or retail fixture’s external power supply.
Bring selected cabinet-door and maintenance contacts into a store’s equipment monitoring view.
Supervise an allowed enable request for a selected fixture accessory, such as display lighting or a ventilation unit.
Connect the RTU to documented auxiliary signals from an existing PLC-controlled system. The PLC retains its process sequence, interlocks and safety functions; selected physical interfaces and protocols must be established for each integration.
Publish selected PLC running and summary-fault states for remote operations and maintenance review.
Read a small set of discrete process or sequence states so remote operators can interpret where the equipment is in its operating cycle.
Read compatible analogue transmitter signals associated with a PLC-controlled process for a separate remote monitoring view.
Provide a defined external request to an existing PLC input when the control design permits supervisory enable or inhibit commands.
Provide an agreed acknowledgement or maintenance request through a documented external PLC interface.
Connect compatible external instruments and auxiliary facility signals for environmental operations. The selected probes and transmitters define the measured substances, ranges and performance; the RTU acquires their available signals.
Bring selected gas or air-quality transmitter outputs into a location-based monitoring view.
Collect selected conditioned outputs from external water-quality instruments for treatment or discharge supervision.
Identify whether a selected treatment skid or auxiliary unit reports running, stopped or faulted.
Monitor a selected differential-pressure measurement or filter switch alongside available extraction-unit feedback.
Connect operating feedback and permitted requests for an external sampling pump or instrument accessory.
Connect selected environmental transmitters, irrigation equipment states and permitted auxiliary commands. Water delivery and crop-management decisions depend on the selected instruments and the site’s agronomic and hydraulic design.
Collect external temperature and humidity signals at selected greenhouse zones for operating visibility.
Keep a requested irrigation-valve action separate from the available valve-position or line-state feedback.
Monitor selected compatible pressure-transmitter signals around an irrigation supply or distribution point.
Combine an external storage-level measurement with selected pump running or fault signals.
Acquire selected conditioned measurement outputs or service-state contacts from an external dosing or fertigation package.
Bring cabinet events, external measurements and auxiliary operating requests into the maintenance workflow for distributed sites. Select power, communication and protective installation arrangements against the actual site conditions.
Associate selected door-open and maintenance-mode events with the correct remote cabinet or station.
Read selected external power-supply or backup-system alarm contacts for remote service response.
Combine a compatible external temperature measurement with fan running or fault feedback.
Read selected analogue outputs from external battery-monitoring or station utility transducers.
Bring a leakage contact and selected station auxiliary states into the same site monitoring view.
Connect selected machine and package signals for operating visibility and permitted supervisory control. The host equipment retains its process control, interlocks and independent protective functions.
Make selected auxiliary machine states available for production support and service assessment.
Associate selected running, loading or trip indications with the correct compressor asset.
Connect compatible temperature or pressure measurements with available pump or fan status signals for a cooling package.
Monitor the relationship between an approved actuator command and its available end-position signals.
Identify selected maintenance or service-mode signals so operators can interpret equipment events during planned work.
Monitor selected roadside and transport-facility support equipment through documented auxiliary interfaces. Traffic-signal phases, railway interlocking, emergency controls and other safety functions remain with their dedicated systems.
Identify compatible cabinet-door and equipment-fault signals at a defined roadside asset.
Connect external temperature measurements with available ventilation-unit feedback for a roadside equipment cabinet.
Acquire selected conditioned outputs from site weather instruments for transport-facility operating awareness.
Combine selected level or leakage events with drainage-pump running and fault indications at a transport facility.
Provide a defined local or remote request for a supported non-safety auxiliary, such as service lighting or an equipment-cabinet accessory.
CONFIGURATION & SPECIFICATIONS
The HD20-4000 series supports project-selected I/O arrangements. The reference configuration below is 4DO + 4DI + 4AI. The product image shows a unit labelled HD20-4021GD; the final ordering code, fitted interfaces and electrical limits follow the agreed configuration-specific specification.
| Product family | HD20-4000 Series IoT Controller / RTU |
|---|---|
| Illustrated model | HD20-4021GD; 4G-labelled device |
| Reference I/O configuration | 4 digital outputs + 4 digital inputs + 4 analogue inputs |
| Digital inputs | 4 channels in the reference configuration. Request the input electrical type, thresholds and wiring specification. |
| Digital outputs | 4 channels in the reference configuration. Request the output type, permitted load and switching-interface specification. |
| Analogue inputs | 4 channels in the reference configuration. Request the supported signal range, accuracy conditions and scaling specification. |
| Edge processing | Supported; application logic and signal interpretation follow the selected configuration. |
|---|---|
| Control modes | Local / remote / condition-based |
| Operating roles | Master/slave working modes; interface, protocol and role selection are defined for the project. |
| Watchdogs | Software and hardware watchdog mechanisms |
| Sampling, reporting and response | Define input sampling, data reporting, event processing and control-response requirements separately. |
| Start-up and lost-link behaviour | Specify output states, permitted local actions and recovery behaviour for the delivered configuration. |
| Cellular variant shown | 4G; select the regional module, bands, SIM service and antenna arrangement for the installation. |
|---|---|
| Hitelecom Cloud | Online viewing of uploaded monitoring data and alerts above configured thresholds. |
| Customer platform | Project-specific integration; agree the supported device interface, protocol and data mapping. |
| Remote configuration | Supported for the applicable device settings. |
| Remote firmware upgrade | Supported; use the approved firmware and maintenance procedure for the supplied configuration. |
| Power supply | Request the rated input range, polarity, peak/typical consumption and wiring requirements. |
|---|---|
| Form and installation | Compact enclosure; select mounting, cable routing and service clearance for the installation. |
| Dimensions and mass | Refer to the configuration-specific mechanical drawing and product specification. |
| External equipment interfaces | Match the controller I/O electrical specification to each instrument, actuator or load-control circuit. |
| Installation environment | Select the device and any protective cabinet against the site temperature, humidity and exposure conditions. |
|---|---|
| Ingress protection | Request the rating and installation conditions for the supplied device configuration. |
| Commissioning information | Signal schedule, control permissions, equipment feedback, remote settings and recovery checks. |
| Conformity documentation | Request model- and destination-specific declarations or test documentation for the ordered version. |
Select external instruments, loads and control circuits against the supplied electrical specification. Independent equipment protection and required safety functions remain part of the installation design.
PLATFORM & INTEGRATION
View uploaded monitoring data online, follow equipment states and receive alerts when configured thresholds are exceeded. Connect the controller’s digital and analogue points to meaningful asset names, units and operating conditions. Customer-platform integration can be scoped around the selected device interface and data exchange requirements.
Online data: bring equipment states and external measurement values into the selected monitoring view, with units and update behaviour defined for each point.
Threshold alerts: set the relevant monitoring limits and notification workflow. Verify the alert condition, recipient and delivery during commissioning.
Control and integration: agree the permitted remote actions, feedback points and local priorities. Define the protocol and data mapping separately for a customer-platform project.
ANSWERS FOR YOUR PROJECT
Answers for interface selection, control modes, cloud access and commissioning.
It combines field data acquisition, equipment monitoring and control in an IoT RTU. Digital inputs capture equipment states, analogue inputs receive compatible transmitter signals, and digital outputs connect to permitted control circuits. Edge processing, cloud monitoring and remote maintenance support the operating workflow.
The reference arrangement is 4DO + 4DI + 4AI: four digital outputs, four digital inputs and four analogue inputs. The series supports project-selected I/O arrangements. Confirm the channel allocation and obtain the electrical specification for the ordered version. The 40 application tasks are selection examples, not 40 simultaneous channels; a larger point list may need another configuration or additional controllers.
DI points acquire compatible digital equipment states; AI points acquire compatible analogue transmitter outputs. Match electrical logic, signal ranges, isolation and accuracy conditions to the selected version and external instrument. Provide the instrument output specification during selection. A DO, DI or AI label alone does not establish a relay topology, a voltage/current range or a communication protocol.
The series supports local, remote and condition-based control. For each action, define the triggering condition, command priority, permitted operating scope and available feedback. Connect outputs through electrically compatible control interfaces. The host equipment retains its sequence, interlocks and independent protection functions.
These are working roles for project-defined device coordination. Identify which device initiates an exchange, which responds, and the data or commands involved. Select the actual interface, communication protocol and supported operations for the project. The master/slave description by itself does not establish a serial port type or a particular protocol.
Yes. Hitelecom Cloud supports online viewing of uploaded monitoring data and alerts when configured thresholds are exceeded. Configure the measurement units, equipment-state meanings, limits and notification workflow for the connected points. Data availability and notification timing depend on the device reporting profile and network connection.
Customer-platform, PLC, machine and shelf-system integration is reviewed against the interfaces supported by the selected configuration. Agree the physical connection, protocol where applicable, point definitions, permitted commands and equipment-feedback mapping. Connection to an auxiliary signal does not establish native compatibility with a machine, electronic shelf-label network or payment system.
The series uses hardware and software watchdog mechanisms to support recovery from defined faults. They are device-recovery features, not a guarantee of uninterrupted operation or a replacement for equipment protection. Commissioning should verify the applicable reset behaviour and the resulting output states.
The series supports remote configuration and remote firmware upgrades. Use the settings and firmware intended for the delivered hardware configuration, and plan maintenance around the site operating procedure. Verify the required settings and device operation after the change.
Local and condition-based control are supported operating modes, but lost-link operation, output fallback states and start-up recovery must be specified for the delivered configuration. A remote command path and an online monitoring view depend on connectivity. Test the agreed interruption and recovery behaviour at commissioning.
Select the connection using the output electrical type, the permitted load and the equipment interface. A suitable starter, contactor, intermediate switching device or actuator control circuit may be required. Output activation alone does not prove that a motor is running or a valve has reached position; use available equipment feedback.
Provide the installation country, signal list, instrument output specifications, equipment-control interfaces, required local/remote priorities, power source and site conditions. Include the target platform and the expected behaviour during communication loss or restart. These details establish the I/O allocation, integration scope and any customization requirements.
LET'S TALK ABOUT YOUR PROJECT
Share the instrument outputs, equipment-state points, permitted commands and feedback required at the site. We will review the 4DO + 4DI + 4AI reference allocation against the signal list, define local and remote priorities, and scope Hitelecom Cloud or customer-platform integration.
sales@hitelecom.cn ↗
