Cabinet PLC timing: NTP or Modbus absolute time?

Production and automation cabinets need an inspectable on-prem time source for PLCs, IPCs, and logs. Single-port LAN NTP with one AC or DC inlet and front-panel LOCK checks; plan capacity from the datasheet formula.

Primary: SY-1231

Fit Production and automation cabinets: tens of clients, single LAN port, inspectable on-prem time.

Not for Must-have IEEE 1588 stamp or IRIG-B (4096); or separated mgmt/timing ports / dual supply (8640 roadmap).

Acceptance facts

  • One SY-1231 can serve Ethernet NTP, RS-485 Modbus absolute time (incl. ms), TTL 1PPS, and minute PULSE together.
  • PLC/SCADA polling uses Modbus (1 ms resolution); IPCs and logs use NTP. The two channels are not interchangeable metrics.
  • Single-path -S power: one AC or DC inlet at a time. Confirm LOCK on the front panel before accuracy-related acceptance.

Cite these sources

FAQ

Can we use NTP only and skip RS-485?
Yes. Enable Modbus / 1PPS / PULSE only if wired. Write the RFQ against the interfaces you will use.
Default address?
192.168.1.123/24. Allow UDP 123 on the cabinet switch or firewall.

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