The HE command enables encoder index, and phase A and B signals to be considered in addition to the home switch input when an HM or HR command is executed. This command does not execute the home motion which must be initiated with an HM, HR, KM, or KR command.
Default home behavior (considering only the home switch for home commands) may be reestablished via the HS command. In the HE mode, home is defined as the logical AND of the encoder index, the external home enable and the encoder quadrant where channel A is positive and channel B is negative. The default home logic expressed in Boolean terms is:
home = phase_A / phase_B index / home_switch The HL and HH commands are not valid in this state.
.
Example: Set up the Y axis so it will use the encoder signals to recognize the home position.
Enter: AY;
HE;
or AA;
HE,1;
Response: None
QUEUE REQUIREMENTS
FORMAT MODE REQUIREMENTS
HE AX – AT Immediate
HEb,b,b,b; AA-AM Immediate
- AA/CD Not Valid
Related commands: HM, HR, HS, KM, KR
4BCOMMAND STRUCTURE 47BCOMMAND DESCRIPTIONS
HF HOLD OFF
The HF command disables position hold, stall detection and tracking modes, for stepper with an encoder axis. If the current axis is a servo, this command will open the loop and turn off the PID.
If the current mode is multi-axis, all axes will go into open-loop mode. This is the default mode at power up or reset.
Example: Turn off encoder hold mode on the X axis.
Enter: AX;
HF;
Response: None
NOTE: In AA or AM mode, a null value in the argument list specifies feedback for that axis is not to be disabled.
QUEUE REQUIREMENTS
FORMAT MODE REQUIREMENTS
HF; AX – AT 2
HF; AA-AM 2
- AA/CD Not Valid
Related commands: HN, ?PM
47BCOMMAND DESCRIPTIONS 4BCOMMAND STRUCTURE
HG HOLD GAIN
The HG command allows the user to specify the position hold gain parameter. This gain parameter is multiplied by the position error in determining the velocity during correction. The velocity used will not exceed the value set with the hold velocity (HV) command. This command is designed to work with stepper motor applications using encoders and is not designed for use with servo motors. The parameter should be set experimentally by increasing it until the system is unstable then reducing it slightly below the threshold of stability. The factory default value is 1.
See the AP command (page 5-43) to preserve the HG settings as the Power up/Reset values.
RANGE: 1 ≤ HG ≤ 32,000 Example: (see HN command (page 5-92)
QUEUE REQUIREMENTS
FORMAT MODE REQUIREMENTS
HG#; AX – AT 2
HG#,#,#,#; AA-AM 2
- AA/CD Not Valid
Related commands: HD, HF, ?HG, HN, HV
?HG REPORT POSITION MAINTENANCE GAIN
The ?HG command reports the current setting of the position maintenance hold gain constant for the current axis. This command works only with stepper with encoder axes.
Example: Position corrections seem slow. Check the setting of HG to be sure it is correct.
Enter: ?HG Response: hg100<LF >
QUEUE REQUIREMENTS
FORMAT MODE REQUIREMENTS
4BCOMMAND STRUCTURE 47BCOMMAND DESCRIPTIONS
HH HOME HIGH
The HH command sets the sense of the home switch on the current axis to active TTL high. This command allows TTL logic high to be treated as the “true” state for applications where this is more convenient. Once this command has been sent to the PCIx, active high homes can be made the power-up default by using the AP command; refer to the AP command for details. This command sets the home switch “true” state to TTL logic high for the HS mode of the home operation and it is not valid in HE mode..
Example: (see HL command on page 5-89)
Note: In AA or AM modes, a null argument in the parameter list specifies that axis home switch to be unchanged.
QUEUE REQUIREMENTS
FORMAT MODE REQUIREMENTS
HH; AX – AT 1
HHb,b,b,b; AA-AM 1
- AA/CD Not Valid
Related commands: HL, HM, HR, HS, KM, KR
HL HOME LOW
The HL command sets the sense of the home switch on the current axis to active TTL low. This is the power-up and reset default “true” state unless HH has been saved as a user power-up default (See the AP command.). This command sets the “true” state of a home input to a TTL logic low.
This command sets the home switch “true” state to TTL logic high for the HS mode of the home operation and it is not valid in HE mode..
Example: The stage is moved through home with the home switch set for active low at low speed to meet the less than 2048 steps per second requirement of the home command.
Note: In AA or AM modes, a null argument in the parameter list specifies that axis home switch to be unchanged.
QUEUE REQUIREMENTS
FORMAT MODE REQUIREMENTS
HL; AX – AT 1
HLb,b,b,b; AA-AM 1
47BCOMMAND DESCRIPTIONS 4BCOMMAND STRUCTURE
HM HOME
The HM command will cause the current axis or specified axes to move in the positive direction at the predefined velocity until the home is detected for each axis. The position counters will be initialized to the positions supplied as parameters.
How home is detected depends on whether the HS or HE modes has been selected. The default mode, HS, detects home based on an external home input only. The HE mode detects home based on the external home input and the encoder signals (Index, A and B).
The velocity should be less than the update rate to maintain accuracy of the home position loaded. A velocity set to less than or equal to the update rate will provide a homing accuracy of +/-0 counts. Every multiple of the update rate adds +/-1 count to the error range.
Each axis will, when home is detected, reset its position counter to the parameter specified in the HM command. Once the counter is reset, the axis will ramp to a stop at the rate specified previously via the AC command. This will result in the axis stopping beyond the home switch so care should be taken to ensure adequate stopping distance is available beyond the switches.
The axis can be easily returned to the precise home position by using an MA command after the HM command.
If no parameter is specified in single axis modes, the HM command will use zero as a default value. Parameters must be specified in multi-axis modes to inform the PCIx which axes are to be homed.
Example: Find the physical home position of the X axis of the stage. The motor runs until the home switch input is activated and then initializes the position counter to the parameter supplied. Since the motor decelerates to a stop after reaching home, it is necessary to do an MA to the same position as specified in the home command if it is desired to physically position the device at home. The following commands will find home, initialize it to 1000 counts, and then return to home. In many cases it will not be necessary to return home, only find the position and synchronize the controller to it.
4BCOMMAND STRUCTURE 47BCOMMAND DESCRIPTIONS