System variables

System time

Available for AXC F x152, RFC 4072S, and RFC 4072R

Note: For RFC 4072R, see additional variables in System variables - Redundancy.

The RTC system variable is a system variable organized as a data structure. The RTC system variable can be used to retrieve information on the system time of the device's internal real-time clock (in short, RTC). This RTC system variable delivers date and time as local time (not as UTC±0).

RTC system variables

System variable	Type	Description
RTC	RTC_TYPE	Data structure
└ HOURS	USINT	System time (hours)
└ MINUTES	USINT	System time (minutes)
└ SECONDS	USINT	System time (seconds)
└ DAY	USINT	System time (day)
└ MONTH	USINT	System time (month)
└ YEAR	UINT	System time (year)

Note: From PLCnext Engineer version 2023.6 and firmware version 2023.6 the function GET_MICROSECONDS is available to return a timestamp in microseconds since system start.

PLC_CRC_PRJ

Available for RFC 4072S, RFC 4072R, SPLC 1000

The PLC_CRC_PRJ system variable provides the CRC of the non-safety-related project.

System variable	Type	Description
PLC_CRC_PRJ	ULINT	The CRC of the non-safety-related project

IP socket function blocks

Available for AXC F x152, RFC 4072S, RFC 4072R

You can use the TCP_SOCKET and UDP_SOCKET function blocks to open and close the IP sockets that are used for IP communication via Transmission Control Protocol (TCP) or via User Datagram Protocol (UDP).

You can use the TLS_SOCKET function block to open and close IP sockets that are used for secure IP communication via Transport Layer Security (TLS).

You can retrieve the number of opened IP sockets using the following system variables:

IP socket system variables

System variable	Type	Description
IP_ACTIVE_SOCKETS	UINT	Number of IP sockets opened using the TCP_SOCKET and/or UDP_SOCKET function blocks
TLS_ACTIVE_SOCKETS	UINT	Number of IP sockets opened using the TLS_SOCKET function block

Device state

Available for AXC F x152, RFC 4072S, RFC 4072R

For RFC 4072R, see additional System variables - Redundancy.

The DEVICE_STATE system variable is a system variable organized as a data structure. The DEVICE_STATE system variable can be used to retrieve various information on the device status of the controller.

Device status system variables

System variable	Type	Description
DEVICE_STATE	DEVICE_STATE_X152_TYPE	Data structure
└ BOARD_TEMPERATURE	SINT	Temperature inside the housing (in °C)
AXC F 3152, RFC 4072S └ FAN_FAIL AXC F 1152, AXC F 2152 └ reserved1	BOOL	AXC F 3152, RFC 4072S: The fan is defective. Device defect due to overheating Immediately replace the fan when the defect occurs. Note concerning AXC F 3152: This feature is only available up to hardware revision 03. AXC F 1152, AXC F 2152: Reserved
RFC 4072S └ RAMDISK_USAGE AXC F x152 └ reserved2	USINT	RFC 4072S: Memory used on the RAM disk AXC F x152: Reserved
└ CPU_LOAD_ALL_CORES	USINT	Average current utilization of all processor cores (in %)
└ CPU_LOAD_PER_CORE	CPU_LOAD_PER_CORE_ARRAY	Information on the utilization per processor core
└ [1]	USINT	Current utilization of processor core 1 (in %)
└ [2]	USINT	Current utilization of processor core 2 (in %)

Fan state

Available for AXC F 3152, RFC 4072S, RFC 4072R

Note: For RFC 4072R, see additional variables in System variables - Redundancy.

The FAN_STATE system variable is a system variable organized as a data structure. The FAN_STATE system variable can be used to retrieve maintenance or failure information on the optional fan module.

System variable	Type	Description
FAN_STATE	FAN_INFO	Data structure of the fan system variables
└ FAN_MAINTENANCE	BOOL	Fan maintenance is required
└ FAN_DEFECT	BOOL	Fan is defective

User partition

Available for AXC F x152, RFC 4072S, RFC 4072R

Note: For RFC 4072R, see additional variables in System variables - Redundancy.

The USER_PARTITION system variable is organized as data structure. The USER_PARTITION system variable can be used to retrieve various information and memory statistics about the user partition (Overlay file system). The partition can be located on an SD card or on the internal memory. This memory is organized in blocks. A block has a constant, fixed size, and a file always occupies one or more blocks.

A certain number of blocks is reserved in the Linux system for the root user. Those reserved blocks are only available for the root user and ensure that the root user is able to act even if the memory is occupied (e.g. for log output).

User partition system variables

System variable	Type	Description
USER_PARTITION	PARTITION_INFO	Data structure
└ MEM_TOTAL	ULINT	Total memory of the partition in bytes (including reserved blocks)
└ MEM_FREE	ULINT	Free, available memory in bytes (without reserved blocks)
└ MEM_USED	ULINT	Occupied memory in bytes (including reserved blocks)
└ MEM_USAGE	USINT	Used memory in % (without reserved blocks)

Utilization monitoring

The utilization of the user partition is monitored by the firmware. The utilzation is shown in the cockpit pages of PLCnext Engineer and WBM.

Furthermore the utilization is shown in IEC 61131‑3 system variables:

In case the utilization of the user partition exceeds 90 % an Arp.Device.Interface.UserPartitionUsage.Critical notification (severity: Warning) is emitted.
At the same time, the Arp.Device.Interface.DeviceInterface emits a message “Filesystem usage critical: 90 %” (severity: WARN) to the output.log.
In case the utilization is decreased to 85 % or less another notification Arp.Device.Interface.UserPartitionUsage.Changed (severity: Info) is emitted.

UPS diagnostics

Available from firmware 2022.6 for all PLCnext Control devices with an integrated UPS

Some PLCnext Control devices have an integrated UPS (Uninterruptible Power Supply). In the event of a power supply failure, the device is shut down with the aid of this UPS, whereby the values of the retain variables in particular are saved. The information about the state of charge as well as the functionality of the UPS is particularly important and is therefore provided via the following system variables from firmware release 2022.6:

System variable	Type	Description
UPS_DIAGNOSTICS		Data structure
└ CHARGE_LEVEL	INT	UPS charge status in %
└ HWARN	BOOL	`Health Low` - warning bit of the status register The notification UPS health warning is emitted (refer to WBM - Notifications page).
└ HFAIL	BOOL	`Health Failure` - warning bit of the status register The notification UPS health failure is emitted (refer to WBM - Notifications page). Important: If the system variable `UPS_DIAGNOSTICS.HFAIL` is `TRUE` then the controller must be sent to Phoenix Contact for repair. This applies to the controllers AXC F 3152, RFC 4072S and BPC 9102S. Please contact Phoenix Contact or your local subsidiary for further details.

The function block UPS_DIAGNOSTICS can also be used to read out diagnostic or status information from the UPS. For more information on the function block refer to the PLCnext Engineer help.

The WBM page Integrated UPS also displays the values and messages of the UPS. You can find further information in Diagnostics - Integrated UPS.