PLCs for Medical Equipment Companies

Project Scope

Maple Systems was contracted by Seth Warnock, Chief Designer for Nelco Worldwide to perform applications engineering for the development of three separate programs. The first program is to replace the current Panasonic AFPORC14CRS controller on their radiation medical swing door with a Maple System PLC.

Develop a project for a Maple Systems PLC which include functional logic necessary to meet the features and functions described below for their medical radiation doors. Nelco provided our Engineering team with a list of parameters for use in the PLC logic.

General Door Operation

INPUTS
Open Command: Push once to Open NO Momentary Contact
Stop Command: Push once to Stop NO Momentary Contact
Close Command: Push once to Close NO Momentary Contact
Partial open command: Push for partial open - push again to close NO Momentary Contact
Push to open, push to close: Push once to open, push again to close NO Momentary Contact
Tape Switch Safety Input: Reverses a door when opening or closing NO Momentary Contact (safety circuit)
Super Scan Safety Input: Reverses a door when closing NO Momentary Contact (safety circuit)
Door Disable: Contact activation that disables door in full open/full closed position (for framed mounted sensors)
NO Maintained Contact (safety circuit)

DOOR POSITION
RTDP: Real time door position The current position of the door
Closed: Door in Closed position User can change value
Open: Door in Open position User can change value
Partial: Door opens to predetermined position User can change value
Latch Check: Point at which door changes speed to ease into closed position User can change value
Back Check: Point at which door changes speed to ease into open position User can change value

PLC Logic

FUNCTION

Open commanded:

• Don’t open the door if any of the safety inputs are triggered
• Don’t open the door if its already open
• If the door encounters an object even if none of the safety are triggered, reverse and close the door
• While opening OR closing always monitor the safety circuits and if triggered, reverse the door direction.

Stop Command:

• Immediately stop the door regardless of door position or direction

Close Command:

• Do not close the door if any of the safety inputs are triggered
• Do not close the door if its already closed
• Close the door but:
• If the door encounters an object even if none of the safety are triggered, reverse and open the door (Entrapment Protection)
• Always monitor the safety circuits and if triggered, reverse the door direction.

Partial Open Command:

• If the door is open, do nothing
• If the door is closed, open to Partial position
• If the door is in Partial position and the Partial (or Close) is pushed again, close the door but:
• While opening OR closing always monitor the safety circuits and if triggered, reverse the door direction.
  • If the door encounters an object even if none of the safety are triggered, reverse and open the door (Entrapment Protection)
  • Always monitor the safety circuits and if triggered, reverse the door direction.

Push to open, push to close:

• Pressing the switch once opens the door, while pressing it again closes the door.
• Reversing the direction of the door while it’s moving (dynamic) can be accomplished with any input.

Tape Switch (TS) Safety Input:
The TS is a pressure sensitive safety edge/bump strip providing collision and contact protection:

• Reverses a door when opening (TS is mounted in the “pull” side of the door)
• Reverses a door when closing (TS is mounted on the “push” side of the door)
  Note: separate terminal connections are required for each TS

Super Scan Safety Input:

• Input for door mounted presence sensor such as the BEA SuperScan (active infrared sensor).
• The sensor can be mounted on either side or both sides of the door. Reverses a door when closing or opening.

Door Disable:

• Presence sensors that are frame mounted, such as the BEA Bodyguard (DK-12), can be used to disable any door movement when the door is in the open or closed position. This feature does not prevent the door from being activated when any position other than fully open or fully closed

Entrapment Protection:

• Reverse direction of the door when an object is detected.

Auto Close:

• The operator is programmed to automatically clamp the door against the frame after each cycle. The motor should shut off after being in contact with the frame for about 5 seconds. The Auto Close feature is a value which if exceeded the operator ‘clamps’ the door back into the frame. The value for the auto close feature is normally 30 units higher that the RTDP while against the door jamb

Our Value Promise

Long renowned in the Industrial Automation industry for the quality of technical support we have provided for decades, Maple Systems has a reputation for connecting customers with someone who knows our products inside and out. Whether it is one of our trusted System Integrator partners, Distributors, or our own engineering team, we are happy to connect you with a knowledgeable engineer dedicated to understanding your application.