PACFramework

LVL2 Classes

CLSID=16#200x – 16#27FF

General description

LVL2 (devices) – the device and actuator layer, intended for convenient process debugging, simulation modeling functions, process alarm functions, and statistics tracking:

• actuators (shut-off valves, control valves, motors, pumps);
• control and regulation loops for feedback control functions;
• other devices that include several process variables and have dedicated states.

It is recommended to use consistent ID-based identification for device and actuator variables within the LVL2 layer to simplify symbolic referencing in HMI.

The device and actuator layer heavily depends on the specific implementation of actuator control schemes and may differ significantly across different integrators.

• VLVD (CLSID=16#201x) – valve with discrete control,
• VLVA (CLSID=16#202x) – valve with analog control,
• VLVS (CLSID=16#203x) – SERVO-type valves,
• DRV (CLSID=16#204x) – motors.

A variable with ID 0 is reserved as an empty, inactive variable.

Recommendations for HMI use

An example of device and actuator diagnostics and configuration in HMI is shown in the figures below.

Fig. Example of an actuator control window on HMI.

Fig. Example of an actuator control and configuration window on HMI.

Variable statuses (alarms, failures, forcing) accompany actuator display on all HMI mimic diagrams. The following figure shows an example of warning display for an actuator.

Fig. Example of displaying actuator statuses on HMI.

General Requirements for the Structure of Actuator Class Variables

When implementing control functions, universal actuator structures are used: ACTTR_CFG (configuration variables), ACTTR_STA (status bits), ACTTR_ALM (alarm bits), ACTTR_PRM (parameter bits), with a unified buffer using an identical structure ACT_CFG.

ACTTR_STA

This structure is used to describe the statuses of a universal actuator and contains all status bits of defined actuators. It is also used as a universal internal structure within the actuator processing function.

name	type	Description
IMSTPD	BOOL	=1 stopped in intermediate position
MANRUNING	BOOL	=1 moving in undefined direction (manual from local panel)
STOPING	BOOL	=1 stopping
OPNING	BOOL	=1 opening
CLSING	BOOL	=1 closing
OPND	BOOL	=1 open (16#0080)
CLSD	BOOL	=1 closed (16#0100)
MANBXOUT	BOOL	=1 manual mode active from local panel
WRKED	BOOL	=1 in operation
DISP	BOOL	=1 remote mode (from PC/operator panel) (16#0200)
MANBX	BOOL	=1 manual mode from panel (via feedback)
INBUF	BOOL	=1 variable in buffer
FRC	BOOL	=1 at least one variable in the object is forced (for commissioning visibility)
SML	BOOL	=1 simulation mode
BLCK	BOOL	=1 blocked
STRTING	BOOL	=1 starting
STOPED	BOOL	=1 stopped (16#0100)
SLNDBRK	BOOL	=1 sensor fault
CMDACK	BOOL	=1 command acknowledged
SPD1	BOOL	=1 operating at speed level 1
SPD2	BOOL	=1 operating at speed level 2
STA_b21	BOOL	reserved
STRT_DELAY	BOOL	=1 start delay active
STOP_DELAY	BOOL	=1 stop delay active
DBLCKACT	BOOL	=1 ignore CMDRESOLUTION mode
ISREVERS	BOOL	=1 start with reverse
ISANALOG	BOOL	=1 analog control (for display purposes)
INIOTBUF	BOOL	=1 variable in IoT buffer
SPDMONON	BOOL	=1 speed monitoring enabled (SPDMON)
SPDCALIBRON	BOOL	=1 speed calibration enabled
MAINT	BOOL	=1 out of service
STA_b31	BOOL	reserved

ACTTR_ALM

This structure is used to describe all available alarms of a universal actuator, containing all alarm bits of defined actuators. It is also used as a universal internal structure within the actuator processing function.

name	type	Description
ALMSTRT	BOOL	=1 failed to start (clears on command or state change)
ALMSTP	BOOL	=1 failed to stop (clears on command or state change)
ALMOPN	BOOL	=1 failed to open (clears on command or state change)
ALMCLS	BOOL	=1 failed to close (clears on command or state change)
ALMOPN2	BOOL	=1 failed to open (with 2 limit switch pairs)
ALMCLS2	BOOL	=1 failed to close (with 2 limit switch pairs)
ALMSHFT	BOOL	=1 incorrect state (clears on command or state change)
ALM	BOOL	=1 actuator error (logical OR of alarms)
ALMBELL	BOOL	=1 bell activation command (one PLC cycle)
WRN	BOOL	=1 actuator warning (logical OR)
WRNSPD	BOOL	=1 drive slip warning (%)
ALMSPD	BOOL	=1 drive slip alarm (%)
WRNSPD2	BOOL	=1 drive slip warning 2 (%) (with dual speed monitoring)
ALMSPD2	BOOL	=1 drive slip alarm 2 (%) (with dual speed monitoring)
ALMPWR1	BOOL	=1 no power supply
ALMSTPBTN	BOOL	=1 stop button pressed
ALMINVRTR	BOOL	=1 inverter fault
ALM_b17	BOOL	reserved
ALM_b18	BOOL	reserved
ALM_b19	BOOL	reserved
ALM_b20	BOOL	reserved
ALM_b21	BOOL	reserved
ALM_b22	BOOL	reserved
ALM_b23	BOOL	reserved
ALM_b24	BOOL	reserved
ALM_b25	BOOL	reserved
ALM_b26	BOOL	reserved
ALM_b27	BOOL	reserved
ALM_b28	BOOL	reserved
ALM_b29	BOOL	reserved
ALM_b30	BOOL	reserved
ALM_b31	BOOL	reserved

ACTTR_PRM

This structure is used to describe all available parameters of a universal actuator, containing all parameter bits of defined actuators. It is also used as a universal internal structure within the actuator processing function.

name	type	Description
PRM_b0	BOOL	reserved
PRM_ZWRKENBL	BOOL	=1 external input – feedback on operation
PRM_ZPOSENBL	BOOL	=1 analog feedback on frequency/position
PRM_PWRENBL	BOOL	=1 external power status input
PRM_MANCFG	BOOL	=1 manual configuration control
PRM_ZOPNENBL	BOOL	=1 open sensor available
PRM_ZCLSENBL	BOOL	=1 close sensor available
PRM_AUTOACK	BOOL	=1 automatic alarm acknowledgment
PRM_BTNSTPENBL	BOOL	=1 external STOP button input
PRM_ALMENBL	BOOL	=1 external drive fault input
PRM_SELLCLENBL	BOOL	=1 external local control signal input
PRM_PULSCTRLENBL	BOOL	=1 pulse control scheme (2s command)
PRM_ZRUNENBL	BOOL	=1 external drive running input
PRM_ZSPDENBL	BOOL	=1 external drive speed sensor input
PRM_CRVRSENBL	BOOL	=1 actuator with reverse control output
PRM_BLCKOFSPD	BOOL	=1 stop on speed drop
PRM_NOPRES	BOOL	=1 allow movement without pump running
PRM_b17–PRM_b31	BOOL	reserved

ACTTR_CMD

For software control, simultaneous command execution is often required. Using numerical commands does not allow this since each command has a unique number, allowing only one active at a time. Bitwise commands remove this limitation, although they limit the total number to 32. If more commands are needed, an additional CMD variable can be introduced to hold extra bitwise commands.

This structure describes all available bitwise commands of a universal actuator and is used as a universal internal structure within the actuator processing function.

name	type	Description
OPN	BOOL	Open 16#0001
CLS	BOOL	Close 16#0002
TOGGLE	BOOL	Toggle (open<->close, on<->off) 16#0003
ALMACK	BOOL	Acknowledge alarm 16#0004
ALMRESET	BOOL	Reset alarms 16#0005
BLCK	BOOL	Block 16#0006
DBLCK	BOOL	Unblock 16#0007
STOPTUN	BOOL	Stop auto-tuning 16#0008
TUNING	BOOL	Start auto-tuning 16#0009
MAN	BOOL	Switch to manual (SCADA/HMI) 16#0301
AUTO	BOOL	Switch to auto (SCADA/HMI) 16#0302
PROTECT	BOOL	Enable protection algorithm 16#000A
START	BOOL	Start 16#0011
STOP	BOOL	Stop 16#0012
UP	BOOL	Increase 16#0021
DWN	BOOL	Decrease 16#0022
CRMT	BOOL	Disable local control 16#0314
RESOLUTION	BOOL	=1 enable control 16#000B
REVERS	BOOL	Enable reverse 16#0013
CLCL	BOOL	Enable local control 16#0313
DBLCKACTTOGGLE	BOOL	Toggle ignore CMRESOLUTION 16#000C
STARTDELAY	BOOL	start with delay (auto only)
STOPDELAY	BOOL	stop with delay (auto only)
P_RESOLUTION	BOOL	enable by system pressure presence
BUFLOAD	BOOL	load into buffer
OUTSRVC	BOOL	take out of service
INSRVC	BOOL	return to service
CMD_b27–CMD_b31	BOOL	reserved

ACTTR_CFG

The ACTTR_CFG structure represents a universal actuator structure containing all parameters of defined actuators. It is used as a universal internal structure within the actuator processing function and as the actuator buffer ACTBUF.

name	type	Description
ID	UINT	actuator identifier
CLSID	UINT	actuator class identifier
STA	ACTTR_STA	status bits
ALM	ACTTR_ALM	alarm bits
CMD	ACTTR_CMD	bitwise commands
PRM	ACTTR_PRM	parameter bits
STAHMI1/2	UINT	status bits for HMI
ALMHMI1/2	UINT	alarm bits for HMI
CMDHMI	UINT	HMI commands
PRMHMI	UINT	HMI parameters
T_DEASP	UINT	alarm delay time (0.1 s)
T_OPNSP	UINT	max open time (0.1 s)
POS	REAL	actuator position (0–100%), feedback
rez	INT	reserved for type alignment
STEP1	UINT	step number
CNTPER	UINT	changeover count
CNTALM	UINT	alarm count
T_STEP1	UDINT	step elapsed time (ms)
T_PREV	UDINT	previous call time (ms), taken from PLC_CFG.TQMS
VALPREV	REAL	previous cycle value
POWER_IN	REAL	power, kW
CPOS	REAL	actuator setpoint position (0–100%)
SPD/SPD2	INT	calculated rotation speed sensor 1/2 (%)
SPDWRNSP	UINT	drive slip warning threshold (%)
SPDALMSP	UINT	drive slip alarm threshold (%)
STRT_DELAY	UINT	start delay (0.1 s)
STOP_DELAY	UINT	stop delay (0.1 s)
TQ_TOTAL	UDINT	total operating time (min)
TQ_LAST	UDINT	last run time (s)
FRQ_IN	REAL	current frequency
FRQ_OUT	REAL	set frequency
CURR_IN	REAL	current feedback
SPDMON_DELAY	UINT	speed monitoring start delay (0.1 s)
MSG	UINT	message

General Requirements for Actuator Functions

Functional Requirements

Level 2 Control Modules (CMs) represent actuators, controllers, etc., and include basic control functions (according to ISA-88 terminology). Each CM provides bidirectional interaction with “process variables” for both writing and reading. This enables, in addition to implementing specific functionality for a given CM, the following capabilities at this level:

• considering the process variable status (normal/alarm/validity) and diagnostic information in CM control logic;
• simulating CM operation using an integrated simulation algorithm (if needed) for:
  • advanced model-based process diagnostics;
  • model-based control;
  • simulation mode operation for demonstration/training or system commissioning;
• enabling simulation mode for the CM and all related lower-level CMs;
• collecting statistical information (depending on CM type).

For each Equipment Entity, the function block/algorithm is defined along with data structures (interfaces) for interaction with other subsystems/entities.

The data structure and function/FB behavior are ISA-88 compliant, using state machines, modes, and interfaces defined in the standard.

Level 2 CMs, such as devices and actuators, may use process variables provided as inputs/outputs to the processing function. For optional inputs/outputs, auto-configuration of the actuator is supported, allowing the actuator to adjust input/output processing algorithms based on the available signals (e.g., a valve can operate without limit switches).

Buffer Handling

A classical buffer handling function must be implemented.

• A single buffer is recommended for all actuator types.
• Buffer occupation is verified by matching the class identifier CLSID and actuator identifier ID.
• When the buffer is captured:
  • ACTBUF.STA = ACTTR_CFG.STA
  • ACTTR_CFG.CMD = ACTBUF.CMD if it is not zero (enabling commands from other sources).
• The actuator configuration should be read into the buffer upon receiving commands:
  • update the process variable already loaded into the buffer by setting ACTTR_HMI.CMD = 16#0100.
• The actuator configuration should be written from the buffer upon receiving commands:
  • ACTBUF.CMD = 16#0101.

A parameterized bidirectional buffer function (ACTBUFIN <-> ACTBUFOUT) must also be implemented.

• Two buffers are used:
  • ACTBUFIN (input buffer) – for processing commands (when CLSID and ID match) and writing information to the actuator.
  • ACTBUFOUT (output buffer) – for reading information from the actuator when a read command is received via ACTBUFIN.
• One pair of buffers is recommended for all actuators.
• Buffer occupation is not possible since it is implemented with separate ACTBUFIN and ACTBUFOUT buffers, allowing seamless data transfer for further processing or transfer to the HMI internal buffer (similar to PKW parameter exchange in PROFIDRIVE).
• The actuator configuration should be read into the output buffer when:
  • ACTTR_CFG.CLSID = ACTBUFIN.CLSID, ACTCFG.ID = ACTBUFIN.ID, and ACTBUFIN.CMD = 16#100.
• The actuator configuration should be written from the input buffer when:
  • ACTTR_CFG.CLSID = ACTBUFIN.CLSID, ACTTR_CFG.ID = ACTBUFIN.ID, and ACTBUFIN.CMD = 16#101.

Interface Implementation Requirements

The following parameters should be passed in the interface:

• ACTCFG - INOUT
• ACTHMI - INOUT
• Process variables of actuator sensors (limit switches, local buttons, etc.) - INOUT
• Process variables of actuator outputs (solenoids, starters, etc.) - INOUT

If direct access to external variables from within functions is not possible, pass PLC_CFG, ACTBUF, ACTBUFIN, ACTBUFOUT. Alternatively, other interfaces within PLC_CFG can be used.

User Program Implementation Requirements

In the main program (outside the class function implementation):

• On first startup:
  • initialize variable identifiers (ID),
  • occupy the buffer with a selected variable.

In the class implementation program:

• On first startup:
  • initialize variable classes (CLSID),
  • initialize timing parameters (opening time, alarm delays, etc.),
  • disable alarms on subordinate process variables,
  • T_PREV := PLC_CFG.TQMS,
  • T_STEP1 := 0.

The actuator processing function program consists of the following stages:

• Reading information from the actuator-type variable into the universal actuator variable for unified processing using the xx_to_ACT function (xx corresponds to the actuator class).
• Preprocessing: initializing STA, ALM, CMD, handling INBUF, SML, calculating dt, using the ACT_PRE function.
• Parameter handling: supporting automatic and manual configuration. In automatic mode, parameters are verified based on sensor presence/status, adjusting input/output processing algorithms accordingly. In manual mode, operators manually configure actuator operations.
• Simulation mode processing: modifies actuator behavior for simulation (simulating limit switches and sensors, halting output writes) and propagates simulation states to subordinate process variables.
• Command processing using the standard ACT_CMDCTRL function for all actuators.
• Sensor state handling or logic replacement based on actuator parameters.
• State machine and alarm processing for actuator positions and alarms.
• Actuator control command handling.
• Alarm display, status bit generation, and propagation to the PLCFN function.
• Final processing: updating PLC.CFG, forming actuator STA and ALM, clearing CMD, calculating dt, etc.
• Writing back information from the universal actuator variable to the actuator-type variable using the ACT_to_xx function (xx corresponds to the actuator class).
• Processing ACTBUFIN and ACTBUFOUT buffers.

Testing

General Test List

No.	Name	When to test	Notes
1	ID and CLSID assignment on startup	after function implementation
2	Default parameter initialization	after function implementation
3	Buffer write commands	after function implementation
4	Parameter modification and buffer write	after function implementation
5	Built-in time counter operation	after function implementation
6	PLC counter rollover effect on step time	after function implementation
7	Actuator mode control	after function implementation
8	Actuator control	after function implementation
9	Actuator alarm handling	after function implementation
10	Actuator auto-configuration algorithms	after function implementation

Test execution methods for general and special tests are described in each class’s testing methodology.

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