Hardware Position Capture for Encoder 8 and 9

Using Encoder 8 and Encoder 9 on the ACR controller with INTCAP features (INTCAP, MSEEK, GEAR ON/OFF TRG, CAM ON TRG) requires some special setup and considerations

PRELIMINARY SETUP AND ARMING

1. Encoder 8 or 9 needs to be assigned as the Position Feedback device for an axis. It can be assigned to an unused axis if the encoder is not related to an used axis. This can be done in ACR-View's Configuration Wizard or manually with the ATTACH AXIS command.

For the ACR9000, ENC8 can only be used with AXIS0 - 3, ENC9 can only be used with AXIS4 - 7.

Example for assigning Encoder 8 to Axis 3:
ATTACH AXIS3 ENC8 DAC3 ENC8

See ACR User's Guide Part 1 for more information regarding the ATTACH AXIS command.

2. The axis must be assigned as a "slave" to a coordinate system "master" before the INTCAP-based feature can be armed. This can be done in ACR-View's Configuration Wizard or manually with the ATTACH SLAVE command.

Example attaching Axis 3 to Master 1 in Program 1:
PROG1
ATTACH MASTER1
ATTACH SLAVE0 AXIS3 "A"

3. When arming the INTCAP or INTCAP-based feature, you must specify which CAP register and Capture Parameter to use for this encoder. The CAP defines which register on the encoder FPGA is used to store the captured position (this register is not accessible to users.) The "Capture Parameter" defines where the controller's DSP stores the captured position within the user-accessible system parameters.

Using the setup examples above, here are two ACR9000 examples of INTCAP arming using CAP register (CAP3) and Capture Parameter (P13060) normally associated with Encoder 3.

In PROG1 using Encoder 8 rising Z-channel (rising fifth marker => INTCAP mode 16) :
INTCAP A16 CAP3 P13060

In any PROG using Encoder 8 rising Z-channel:
AXIS3 INTCAP16 CAP3 P13060

Note: Failure to specify CAP will result in "Range error," failure to specify the Capture Parameter will result in "Syntax error." The INTCAP mode used in examples above change for other ACR controllers, consult the ACR User's Guide Part 1 for more INTCAP mode explanation.

CHECKING INTCAP ARMED STATUS

To check arm status, use INTCAP with no arguments.

Example for using ENC2's z-channel to capture ENC8's position and captured position stored in P12292 (note that "P01>" denotes commands were issued at the PROG1 prompt):
P01>intcap a0 cap2 p12292
P01>intcap
AXIS3 INTCAP0 CAP2 P12292

CHECKING IF CAPTURE COMPLETE

The "Capture Complete" flags are directly associated with the "Hardware Capture Parameter" used. If Axiso's hardware capture parameter (P12292)is specified, then flag BIT777 will be set when the capture is complete. The Capture Complete flags are located in the Primary Axis Flags.