Registration

Registration is the process of recording the precise position of an axis when an external event occurs. Registration is commonly used for measurements. For example, consider a photo-eye set up on a conveyor belt, where the position of the belt is measured with a quadrature encoder. By registering the precise position at which the photo-eye is broken and the precise position at which it is reconnected, the length of a widget on the belt can be accurately determined.

The RMC provides registration on quadrature feedback axes only. This is because quadrature feedback is the only type of feedback that can record a position at any given moment, independent of the loop time of the RMC. All other feedback types can only report the position once each loop time (500μs to 4000μsec). Using the programming capabilities of the RMC, such as discrete inputs and the Program Triggers, it is possible to achieve functionality similar to registration with other feedback types, but the accuracy will not be the same as with quadrature feedback.

Registration Inputs

Each quadrature feedback axis can keep track of two independent registration events, called Registration 0 and Registration 1. These registration events can come from a single registration input, or from separate inputs. The table below lists the inputs on which registration can be performed.

Module

Registration Sources

RMC75 QAx or

RMC150 Quad

RegX/PosLim input

RegY/NegLim input

RMC150 UI/O

DI/O inputs R0 and R1

RMC75 Q1

Reg input

RMC200 Q4

Depending on the quadrature input:

Input	Registration Sources Inputs
Quadrature input 0 and/or 1	Reg0, Reg1, Hm0, Hm1
Quadrature input 2 and/or 3	Reg2, Reg3, Hm2, Hm3

RMC200 U14

Reg/Z0, Reg/Z1, D0, D1

RMC200 D24

Depending on the quadrature option:

Option	Registration Sources Inputs
One quadrature input (A,B,Z)	D22,D23,D18,D19
One quadrature input (A,A,B,B) with wire break detection	D22,D23,D18,D19
Two quadrature inputs, using inputs D20&D21	D18, D19
Two quadrature inputs, using inputs D22&D23	D16,D17,D18,D19

Arming the Registration

Issuing the Arm Registration (52) command tells the axis to wait for a registration event. Once this command is issued, the registration is said to be armed. When the registration is armed, the corresponding registration armed status bit will be set (Registration 0 Armed and Registration 1 Armed). Unless the registration is armed, the registration trigger is ignored.

The Arm Registration (52) command also tells the axis which Registration Number (0 or 1) to apply the registration event to, which input the registration will be triggered from, and which edge of the input (rising or falling) will trigger the registration.

Registration Event

If the registration is armed and a registration trigger occurs, the following is done:

The precise position at the time of the registration is latched. The position will be reported in the Registration 0 Position or Registration 1 Position status register.
The corresponding latched status bit will be set (Registration 0 Latched or Registration 1 Latched).
The corresponding armed status bit will be cleared (Registration 0 Armed or Registration 1 Armed).

Once a registration is latched, you must issue the Arm Registration (52) command again to rearm it.

Disarm Registration

To manually disarm a registration, issue the Disarm Registration (53) command. Issuing this command will clear the corresponding Registration Armed status bit (Registration 0 Armed and Registration 1 Armed).