Enclosure Azimuth Control Logic

Owned by Gary Foster
Last updated: Mar 08, 2024
3 min read

Draft of a rewrite for Enclosure Azimuth control after the reconfiguration just completed..
Describes current PLC program organization & structure

Enclosure Azimuth motion is controlled by the EMCS control system.
Control is recently moved from EMCS PLC to ENC_LIC.
ENC_LIC PLC is now referred to as EMCS_LIC.

Azimuth motion is commanded from the ECS or locally.

Following is a description of Azimuth control by PLC routines.

Ready (Az_Ready)

Reports Azimuth ready to operate:

  • PLC (CPU, inputs & outputs, communication, produced/consumed tags)

  • Network health

  • Safety (safety PLC, safety logic, inputs & outputs, communication, produced/consumed tags)

  • Travel limits

  • Electrical (circuit breakers)

  • Drives (control units, communication, infeeds, drives, motors, contactors, brakes, brake modules

  • Position encoders (communication, status)

Safety conditions

GIS interlocks

Emergency stop, Seismic alarm, Fire Alarm

GIS Interlock

image-20240307-234358.png

Trapped keys and doors

Service Ring doors

image-20240307-235825.png

Egress doors

Trapped keys

Hardstop travel limits

Limit switches at the extreme ends of travel

End stops

Checks that position of topple block is in agreement with Azimuth actual position.

Overspeed

not implemented

Safe Limited Speed

not implemented

Auxiliary equipment

Control and operation

ECS_cmds_trajectory

  • Tracking - ECS sends Position Reference and Speed Reference

  • Point to Point - ECS sends Position Reference

  • Jogging - same as Point to Point

  • Offset - similar to Point to Point except the Position Reference is sent as an offset to current position

ECS_cmds_drives

Azimuth drive commands

  • (0) Stop movement

  • (1) Start movement

  • (2) Power on drives

  • (3) Power off drives

  • (4) Power on motors

  • (5) Power off motors

  • (6) Release brakes

  • (7) Engage brakes

  • (8) Reset

Az_Mode

Get communication from ECS and Local functions to set the operating mode:

  • Remote Tracking, Point to Point, Offset, Jog

  • Local Jog, Point to Point

  • Off

Mode is off when safety is not ready.

Az_Sequence

Start / stop drives in an orderly sequence

Stop drives on lost of readiness, loss of safety or loss of running components.

All Az_Sequence outputs are commands to start / stop equipment during operation.

Control

Get signals from Mode, Sequence, and Local inputs.

Generates Local / Remote status.

Generates Azimuth Run command to start the Azimuth.

Enables safety functions.

All components have Interlock conditions to protect equipment. Equipment will only be commanded to run if all interlocks are satisfied.

Most components get a sequence run command. Some components in sync with other components.

All Control outputs are commands to start the Azimuth equipment.

Control_Local

Set correct speeds for each mode of local operation

Produce a Local Speed Reference according to source of the command and enclosure conditions.

Control_Position

Calculate and execute motion for all Remote modes.

Produce a Remote Speed Reference.

Control_Speed

Get Speed Reference from Control_Local and Control_Position.

Based on Mode: Select a Speed Reference to send to the drives.

Monitor and control speed limits from each source based on source, travel limits and safety.

Control_Loop

Get a Speed Reference from Control_Speed.

Convert the signal to RPM.

Smooth the RPM signal (S-Curve) to control rate of speed change to the motors.

If Safety is enabled: Enable Speed Setpoint output to the drives.

Equipment control

Brakes

Drive_Infeed

Control infeeds
Monitor voltage, current, status

Drive_brake_module

Drive_Read, Drive_Write, Drive_Read_Status_304, Drive_Read_Status_305

Communicate with Azimuth drives
Send commands, setpoint
Receives speed, torque, status

Drive_Motors

Control motor contactors
Monitor contactors, overloads, motor temperature

Drive_Motors_Allowed

Select motors to be operated.
Never tested.

Drive_Motor_Fans

Run when drives are running
Monitor fan relays, overloads

Drive_Constants

Physical constants for conversion of nits

End_Stops

HMI

Outputs to the Pendant HMI

Limits

Monitor position
Output signals for

  • Slowdown

  • Soft Limit

  • End of Travel Limit (physical limit switch)

  • Final (safety physical limit switch)

Limits_Bypass

Overtravel interlocks prevent further motion
Bypass helps to operate Azimuth to recover from overtravel

Overspeed_Safety

Not implemented

Position

Barcode reader sensors report linear position.
Convert linear position to Azimuth angle.
Report Azimuth position and health of sensors

Position_voting

Consistency check of all position encoders

Siren

Start up siren

TM54F

Not functional.
Holding place for inputs and outputs related to TM54F safe I/O module in the drive system.

WCS Encoder

Obsolete
Replaced by PXV encoders.

Stop_Timing

Diagnostic only

Position_Sim

For testing only

Drive_Load_Sharing

Obsolete

Load sharing function is removed in the drives.

Drive_Master

Obsolete
Select Master drive for Load Sharing