Protocols and data

BACnet, OPC UA, MQTT, IEC 60870 and IEC 61850, SCADA, wireless networks and data quality.

A reading is useful only when it arrives with the right time, unit and quality. These guides cover the protocols that carry it (BACnet, OPC UA, MQTT, IEC 60870 and IEC 61850) and how to keep the data trustworthy through outages.

Start with SCADA architecture for the big picture, or BACnet vs Modbus for building projects.

Networks and architecture

8 guides · about 91 minutes

  1. Zigbee vs LoRaWAN for energy monitoring: when to use each Choose Zigbee, LoRaWAN or both for energy monitoring. Compare reporting needs, coverage, device classes and the integration work needed before deployment. 13 min
  2. What is SCADA? Architecture and energy use cases SCADA architecture for energy sites: local control and the WAN, protocol and security choices, command evidence from request to meter, replay after outages, and a commissioning checklist. 16 min
  3. Cloud API vs local gateway for energy sites When to take energy data from a manufacturer's cloud API and when to read the equipment through a local gateway: call quotas, timestamps, outages, control, security and hybrid sites. 9 min
  4. Over-the-air firmware updates for IoT devices How Zigbee OTA and LoRaWAN FUOTA deliver firmware to field devices, how long each takes, how images are signed, what fails, and how to run and verify an update campaign. 10 min
  5. IoT interoperability in multi-vendor systems Specify and test a multi-vendor IoT system: protocol roles, register decoding, units, time, quality, security, failure recovery and a twelve-step acceptance test. 20 min
  6. IoT data privacy and GDPR compliance When meter and sensor data becomes personal data under the GDPR, and what that changes in the design, retention and export of an energy monitoring system. 10 min
  7. How to set a static IP address on Windows 11 Give a Windows 11 laptop a fixed IPv4 address to reach a ZGW-20 management port, check the link, open Edge and restore DHCP afterwards. 6 min
  8. How to set a static IP address on Ubuntu Desktop Give an Ubuntu Desktop laptop a fixed IPv4 address with a second NetworkManager profile, reach a ZGW-20 management port, open Edge and switch back to the normal network. 7 min

BACnet and building protocols

7 guides · about 55 minutes

  1. BACnet vs Modbus for building integration BACnet and Modbus compared for building and energy projects: data model, networks, discovery, units, control priority and security, and when to use each or a gateway between them. 10 min
  2. BACnet/IP vs MS/TP BACnet/IP and BACnet MS/TP compared: network, speed, APDU size, token passing, bus capacity with a worked example, common faults, routing between them, and how to read MS/TP controllers in a retrofit. 9 min
  3. BACnet objects, properties and point lists BACnet objects and properties explained: analog, binary and multi-state objects, Present_Value, Units and Status_Flags, the PICS, and how to build a point list another system can use. 6 min
  4. BACnet device instances, addresses and discovery How BACnet identifies and finds devices: device instance numbers, network numbers and MAC addresses, the Who-Is and I-Am services, and how to diagnose a device that does not appear. 5 min
  5. BACnet routing, BBMDs and foreign devices How BACnet messages cross networks: routers and network numbers, BBMDs and broadcast distribution tables, foreign device registration, and how to design discovery across IP subnets. 13 min
  6. BACnet COV vs polling, and data freshness How BACnet change-of-value (COV) subscriptions differ from polling: COV increments, subscription lifetimes, network load, and how to know that a value is still fresh. 8 min
  7. BACnet priority arrays and relinquish How the BACnet priority array works: the 16 command priorities, relinquishing a command with NULL, Relinquish_Default, and how to test a write without leaving an override in place. 4 min

OPC UA and MQTT

5 guides · about 49 minutes

  1. OPC UA vs MQTT vs Modbus OPC UA, MQTT and Modbus compared: data model, status and timestamps, security, ports, a worked example of one meter reading through all three, and the failures to test at commissioning. 10 min
  2. MQTT QoS, retained messages and stale data MQTT QoS 0, 1 and 2, what each acknowledgement proves, retained messages, persistent sessions, last will and message expiry, and how to avoid showing stale telemetry as current. 9 min
  3. What is MQTTS? MQTT over TLS for energy IoT Understand MQTT over TLS: certificates, broker identity, topic access, QoS limits and commissioning checks for trustworthy energy IoT data. 13 min
  4. OPC UA clients, servers and node identity How OPC UA identifies data: clients and servers, endpoints and security, NodeIds and namespace indexes, status codes and timestamps, and how to accept one point through a restart. 5 min
  5. OPC DA vs OPC UA: differences and migration The differences between OPC DA (OPC Classic) and OPC UA, the three ways to migrate, how to map items to nodes without losing quality or time, and how to test the cutover. 12 min

IEC 60870 and IEC 61850

6 guides · about 54 minutes

  1. Choosing grid communications: IEC 101, IEC 104 and IEC 61850 Choose the right communications boundary for an RTU, solar plant, battery or switchgear. Compare telecontrol with MMS, GOOSE and sampled values, then define the point list and acceptance tests. 6 min
  2. IEC 60870-5-101 vs IEC 60870-5-104 IEC 101 and IEC 104 compared: serial polling and TCP port 2404, k, w and t0 to t3, field sizes and time tags, one point in both encodings, and tunnels versus converters. 11 min
  3. IEC 60870 ASDUs, causes of transmission and addresses How to read an IEC 60870-5-101 or 104 point list: type identification, cause of transmission, common address and information object address, with an IEC 104 frame decoded byte by byte. 10 min
  4. IEC 60870 timestamps and quality descriptors How IEC 60870-5-101 and 104 carry time and quality: the CP56Time2a time tag, its invalid and summer-time bits, and the quality flags overflow, blocked, substituted, not topical and invalid. 5 min
  5. IEC 60870 commands, select-before-operate and confirmation How an IEC 60870-5-101 or 104 command works: direct execute and select-before-operate, activation confirmation and termination, command qualifiers, and checking the real equipment state. 10 min
  6. IEC 61850: data models, MMS, GOOSE and SCL IEC 61850 explained for integrators: logical devices and logical nodes, MMS reporting, GOOSE and sampled values, SCL files (ICD, SCD, CID), and how it compares with IEC 60870-5-104. 12 min

Data quality and delivery

6 guides · about 58 minutes

  1. IoT sensor data: timestamps, quality and gaps Define IoT sensor points that survive outages: identity, units, source timestamps, quality, stale limits, counter rollover and the commissioning tests that prove them. 14 min
  2. Telemetry timestamps, source time and arrival time Which timestamp a sensor reading should carry: source time, collection time and arrival time, interval labels, time zones, clock sync, late data and duplicates in energy telemetry. 4 min
  3. Stale, missing and invalid telemetry How to tell stale, missing, invalid and estimated readings apart in energy and IoT data, how to show each one, and how they should affect totals, charts and alarms. 11 min
  4. IoT data storage: architecture and options Compare IoT databases, edge history, replay queues and cloud archives. Size storage, define retention and verify delivery and recovery before deployment. 14 min
  5. Store-and-forward buffer sizing for edge gateways How to size a store-and-forward buffer on an edge gateway: records per second, outage length, storage per record, drain time after recovery, retention limits and full-queue behaviour. 5 min
  6. Industrial polling, backpressure and retries How to budget polling on an RS-485 bus or a Modbus TCP gateway: transactions per cycle, the cost of an offline device, overdue reads and safe retries. 10 min

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