Device Cylinder

Cylinder

This page is generated from the Unity twin. Published from _docs/context/devices/cylinder.md — edit it there, not here. Changes made in the wiki are overwritten on the next sync.

A pneumatic cylinder. Travels between a retracted and an extended end position, taking real time to get there, and reports when it arrives.

Twin device type · twin FB FB_Cylinder · 33 instances in FG_01, FG_03, FG_04, FG_05, FG_Transport · Unity component OC.Components.Cylinder

What it is

The workhorse of the machine: 33 of the 87 devices are cylinders. Stoppers, index lifts, grippers, gates and the press are all cylinders; only the two lift units' carriages are servo axes (DrivePosition). A real one is driven by air through one or two solenoid valves and usually has a sensor at each end of its stroke telling the PLC it has arrived.

What the PLC sees

Symbol	Meaning
Control.0	Retract — drive towards the retracted end
Control.1	Extend — drive towards the extended end
Status.0	At the retracted end
Status.1	At the extended end

Both status bits are false while it is travelling. That is the whole point of simulating it: movement takes time, so a program that assumes an instant arrival fails here exactly as it would on the real machine.

How the twin models it

Travel is a stroke completed over a configured time — half a second by default, separately settable for each direction — mapped onto the part's actual movement through a motion curve. The two end positions are set per instance, so the same component drives a 10 mm gripper jaw and a full index lift stroke.

Three valve types, set per instance:

Type	Behaviour with no command
Double acting	Stays where it is. Moves only while exactly one of the two control bits is set — set both, and it does not move
Single acting, spring retracts	Returns to the retracted end
Single acting, spring extends	Returns to the extended end

Watch out

• An end-position bit is not proof of what the cylinder is holding. Gripper jaws closed on nothing reach the extended end sooner than jaws closed on a part, and the bit is true either way. Only a dedicated part sensor says a part is held.
• A de-energised double solenoid does not hold a gripped part in this twin. The scene wires the cylinder's moving signal to the gripper's grip, so dropping the command drops the part. Grips are re-asserted every cycle for exactly this reason — see the transport behaviour contract.

In this machine

There are 33 of them, in FG_01, FG_03, FG_04, FG_05, FG_Transport:

Device	Twin PLC path	Group	Role / Signal
Y_Gate1	MAIN.FG_01.Y_Gate1	FG_01	Guard gate 1. Must be closed before the FG_01 laser may fire.
Y_Gate2	MAIN.FG_01.Y_Gate2	FG_01	Guard gate 2. Must be closed before the FG_01 laser may fire.
Y_Gripper	MAIN.FG_01.Y_Gripper	FG_01	Double solenoid with both limits read. EXTENDED clamps the payload for marking and reading; retracted releases.
Y_Platform	MAIN.FG_01.Y_Platform	FG_01	Double solenoid with both limits read. Service positioning of the laser head. Never actuated during the production cycle.
Y_ReaderWindow	MAIN.FG_01.Y_ReaderWindow	FG_01	Double solenoid with both limits read. EXTENDED opens the window for the read; retracted shields the optics and is home.
Y_AxisR1	MAIN.FG_03.Y_AxisR1	FG_03	Double solenoid with both limits read. Rotary. Retracted is 0 deg and the receiving orientation; extended is 180 deg and the placing one.
Y_AxisX1	MAIN.FG_03.Y_AxisX1	FG_03	Double solenoid with both limits read. MAX is raised; arm 1 rises once and stays up for the whole cycle.
Y_AxisX2	MAIN.FG_03.Y_AxisX2	FG_03	Double solenoid with both limits read. MAX is the transfer position, min is home over slot 1.
Y_AxisY1	MAIN.FG_03.Y_AxisY1	FG_03	Double solenoid with both limits read. MAX is the transfer position, min is home over slot 2.
Y_AxisY2	MAIN.FG_03.Y_AxisY2	FG_03	Double solenoid with both limits read. The axis factor is inverted, so MAX is LOWERED.
Y_Gripper1	MAIN.FG_03.Y_Gripper1	FG_03	Double solenoid with both limits read. EXTENDED grips. The limit proves the jaws moved, NOT that they caught anything - only B_Detect1 says that.
Y_Gripper2	MAIN.FG_03.Y_Gripper2	FG_03	Double solenoid with both limits read. EXTENDED grips. The limit proves the jaws moved, NOT that they caught anything - only B_Detect2 says that.
Y_AxisZ	MAIN.FG_04.Y_AxisZ	FG_04	Double solenoid with both limits read. EXTENDED presses down onto the part; retracted is clear. A double solenoid so an abort leaves it where it is.
Y_AxisR	MAIN.FG_05.Y_AxisR	FG_05	Double solenoid with both limits read. Rotary. Extended is the fitting orientation, retracted is home.
Y_AxisX	MAIN.FG_05.Y_AxisX	FG_05	Double solenoid with both limits read. MAX is over the pallet, min is over the cap feed.
Y_AxisZ1	MAIN.FG_05.Y_AxisZ1	FG_05	Double solenoid with both limits read. EXTENDED lowers the cap onto the part on the pallet side.
Y_AxisZ2	MAIN.FG_05.Y_AxisZ2	FG_05	Double solenoid with both limits read. EXTENDED lowers to the cap at the pick position on the feed side.
Y_CapsSourceStopper	MAIN.FG_05.Y_CapsSourceStopper	FG_05	Double solenoid with both limits read. EXTENDED BLOCKS the feed path and the queue accumulates against it. The opposite sense to a transport stopper.
Y_Gripper	MAIN.FG_05.Y_Gripper	FG_05	Double solenoid with both limits read. EXTENDED grips the cap. The limit proves the jaws moved, NOT that they caught one - only B_Detect says that.
Y_Lift	MAIN.FG_Transport.Index01_Y_Lift	FG_Transport	Double solenoid with both limits read. EXTENDED raises the carriage and fixes the pallet clear of the belt; retracted is home.
Y_Stopper	MAIN.FG_Transport.Index01_Y_Stopper	FG_Transport	Double solenoid with both limits read. RETRACTED (min) holds the pallet; EXTENDING (max) releases it - the blade drops out of the way.
Y_Lift	MAIN.FG_Transport.Index02_Y_Lift	FG_Transport	Double solenoid with both limits read. EXTENDED raises the carriage and fixes the pallet clear of the belt; retracted is home.
Y_Stopper	MAIN.FG_Transport.Index02_Y_Stopper	FG_Transport	Double solenoid with both limits read. RETRACTED (min) holds the pallet; EXTENDING (max) releases it - the blade drops out of the way.
Y_Lift	MAIN.FG_Transport.Index03_Y_Lift	FG_Transport	Double solenoid with both limits read. EXTENDED raises the carriage and fixes the pallet clear of the belt; retracted is home.
Y_Stopper	MAIN.FG_Transport.Index03_Y_Stopper	FG_Transport	Double solenoid with both limits read. RETRACTED (min) holds the pallet; EXTENDING (max) releases it - the blade drops out of the way.
Y_Lift	MAIN.FG_Transport.Index04_Y_Lift	FG_Transport	Double solenoid with both limits read. EXTENDED raises the carriage and fixes the pallet clear of the belt; retracted is home.
Y_Stopper	MAIN.FG_Transport.Index04_Y_Stopper	FG_Transport	Double solenoid with both limits read. RETRACTED (min) holds the pallet; EXTENDING (max) releases it - the blade drops out of the way.
Y_Lift	MAIN.FG_Transport.Index05_Y_Lift	FG_Transport	Double solenoid with both limits read. EXTENDED raises the carriage and fixes the pallet clear of the belt; retracted is home.
Y_Stopper	MAIN.FG_Transport.Index05_Y_Stopper	FG_Transport	Double solenoid with both limits read. RETRACTED (min) holds the pallet; EXTENDING (max) releases it - the blade drops out of the way.
Y_Stopper	MAIN.FG_Transport.Stopper01_Y_Stopper	FG_Transport	Double solenoid with both limits read. RETRACTED (min) holds the pallet; EXTENDING (max) releases it - the blade drops out of the way.
Y_Stopper	MAIN.FG_Transport.Stopper02_Y_Stopper	FG_Transport	Double solenoid with both limits read. RETRACTED (min) holds the pallet; EXTENDING (max) releases it - the blade drops out of the way.
Y_Stopper	MAIN.FG_Transport.Stopper03_Y_Stopper	FG_Transport	Double solenoid with both limits read. RETRACTED (min) holds the pallet; EXTENDING (max) releases it - the blade drops out of the way.
Y_Stopper	MAIN.FG_Transport.Stopper04_Y_Stopper	FG_Transport	Double solenoid with both limits read. RETRACTED (min) holds the pallet; EXTENDING (max) releases it - the blade drops out of the way.

Control implementations

The twin is master for structure, and that is all this page states. Which control function block each instance becomes, its process-image members and its published HMI struct is the control platform's own knowledge base:

• Beckhoff
• Siemens — no knowledge base published yet