Gateway workflow
Configure the RTU-to-SNMP gateway
The gateway polls selected Modbus RTU points as a master and exposes the latest mapped values through an SNMP v1/v2c agent. It can use the app's internal simulator or a physical serial bus as its RTU source.
Choose a Modbus data source
In the Communication panel, choose either internal lab devices or a physical RS-485/COM source. The internal source uses devices configured in the simulator workspace on the same PC. The serial source uses the configured COM port; match its RTU settings to the target device. The gateway workspace has separate Modbus-master response-timeout and idle-time settings.
Configure the SNMP agent
Set the bind address and UDP port, read and write community strings, base OID and station identity. The agent supports SNMP v1 and v2c. Community strings in these protocol versions do not encrypt or authenticate traffic securely. Keep the agent on a trusted, isolated network and use a loopback bind when only a local manager needs access. Do not expose it to an untrusted network.
Map a Modbus point
Each enabled row specifies a point name, slave ID, Modbus area, raw PDU address, data type, access mode and OID suffix. The OID is formed from the configured base OID, suffix and instance .0. Holding registers and coils can be configured for GET or GET/SET; input registers and discrete inputs are read-only.
Boolean points use coils or discrete inputs. UInt16 and Int16 points use one 16-bit register. Float32 uses two consecutive registers. If the target uses a different byte or word order, use the point's swap controls and verify the decoded value against a known device reading.
The gateway converts its point value using the configured scale and offset. Confirm the intended engineering units and integer range before relying on the exposed value. A generated MIB describes mapped points as integer objects.
Polling and errors
Set the point polling interval, response timeout and optional maximum error count according to the device and bus response time. Successful and failed poll counters and point quality are shown in the gateway workspace. Start the gateway, then read the configured OID from an SNMP manager. Use its traffic log to distinguish RTU poll failures from SNMP manager requests.
Export and inspect a MIB
Choose Export MIB to download a MIB definition for enabled points. Load it into the SNMP manager and query the gateway's bind address and UDP port. A MIB file describes object names and types; it does not make the gateway poll a point that is disabled or incorrectly configured.