Public multi-user server. HR/CL register values are shared across all connections (shared last-write-wins) and can be overwritten by another user at any time. Behavior settings are shared too. State lives in memory only. A server restart resets all values. There is no authentication. Limits apply to connection counts per IP and write rates.
An injection fakes a device fault so you can see how your client handles failures. Type exception makes the slave reply with a Modbus error code, delay slows the reply down, timeout does not reply at all and the client gets a timeout. An injection targets the selected slave or address range, lives at most 300 seconds and is visible to all server users. Clear them all with the "Clear injections" button.
Injections are shared by everyone. Every client polling the selected slave right now gets the fault. To avoid staging a drill outage for someone else:
set a short TTL. An empty field means the maximum, 300 s, after which the injection clears itself;
narrow the target to an address range instead of the whole slave;
done testing - clear the injection right away with the ✕ button in the active list;
active injections are visible to everyone here and in the «Journal». If reads suddenly start failing, check here first.