System variables of the safety-related firmware

Available for RFC 4072S, and for AXC F 2152/AXC F 3152 with SPLC 1000

Information on the system variables of the safety-related PLCnext firmware features can be found in the user manuals for the RFC 4072S controller or the safety-related extension module AXC F XT SPLC 1000.

See Hardware documentation for details and links to the user manuals.

COMMUNICATION_STATE

From firmware 2026.6

The system variables SPNS_PLC_COMMUNICATION_STATE and SPLC_PLC_COMMUNICATION_STATE of data type INT represent the communication state between the SPNS proxy and the SPLC. In order to use the system vairable, PLCnext Engineer 2026.6 or newer is required.

System variable Type Description

AXC F XT SPLC 1000 AXC F XT SPLC 3000: 

SPLC_PLC_COMMUNICATION_STATE

RFC 4072S:

SPNS_PLC_COMMUNICATION_STATE

 INT

0 = Not present 
The SPLC is not physically present or cannot be detected.

1= Syncing
Try syncing with the SPLC

2 = IO Exchange
Communication is available: SPLC exchanges data with the SPNS proxy

3 = Hard Failure
Communication to SPLC is lost

 

See also

  1. Introduction to system variables
  2. System variables - Time, IP, Device, CRC
  3. System variables - ESM tasks, HMI, AlarmProgram status
  4. System variables - Axioline F
  5. System variables - PROFINET
  6. System variables - INTERBUS
  7. System variables - EtherNetIP
  8. System variables - Redundancy
  9. System variables - PLC state

 

 

• Published/reviewed: 2026-09-03  ✺  Revision 101 •