HSMS Linktest Timeout While Data Still Flows: Close the Socket Anyway
A swallowed Linktest.req burns T6 while an S1F1 on the same socket answers with a full S1F2 in 0.3 ms, and the host should close the connection anyway.
Industrial Knowledge Inventory
SCADA
Things
Practical notes for host and MES developers who need to understand SECS/GEM and HSMS before they have equipment to test against.
187 entries indexed · EN / KO · updated continuously
Knowledge Map Online
01OBSERVEprocess.stateREAD
02NAMEtag.identifierCLEAR
03ALARMactionable.onlyARMED
04TRENDvalue.contextRISING
05VERIFYpacket.boundaryOK
read → name → alarm → trend → verify
Latest Entries
All entries →An S1F4 Carries No SVIDs — Get the Names From S1F11 First
/SECS/GEM/11 min read
Your HSMS Session Is SELECTED and S1F3 Still Comes Back as S1F0
/SECS/GEM/11 min read
Reading Equipment Constants From the Host: S2F29 for the Namelist, S2F13 for the Values
/SECS/GEM/12 min read
Why Your S6F11 Never Arrives: Getting S2F33, S2F35 and S2F37 in the Right Order
/SECS/GEM/13 min read
The Equipment Stamps Your S6F11, Not Your Host — Checking That Clock With S2F17 and S2F31
/SECS/GEM/11 min read
Why Your S2F41 Comes Back HCACK 2 While the Tool Screen Says ONLINE
/SECS/GEM/13 min read
Field Sections
Start here§01→§02→§03→
SCADA Basics
Core architecture, responsibilities, and vocabulary for HMI/SCADA projects.
Industrial Protocols
Practical notes on Modbus, OPC UA, MQTT, SECS/GEM, and network troubleshooting.
Project Checklists
Templates for naming, alarms, historian planning, commissioning, and field troubleshooting.
Debug without equipment
Reproduce a host-side SECS/GEM problem in your browser.
Explore SECS/GEM message exchanges in the shared browser demo, then compare them with a captured Select failure. It gives you a practical starting point before you have equipment to test against.
What this is
A public technical notebook: definitions, design notes, protocol reminders, checklists, and lessons learned from real industrial automation work. Clarity over marketing, useful references over generic content.