Default: 0x0000
The individual bits of the Mode word determine the way the RMC responds to control commands and parameters. Bit 0 is the LSB and bit 15 is the MSB.
Note: It is highly recommended that the Pop-up Editors in RMCWin be used for editing this and other hexadecimal fields.
Click here for the Mode Bit Map
Bit 15 - Graph Disable
When this bit is set for an axis, the controller will not start logging data for a new graph but it will continue logging data for a previous command if the plot time hasn’t expired. This is useful for troubleshooting long sequences of moves. The Graph Disable bit can also be set when an error occurs so that the following commands will not restart the data logging and write over the previous graph data that shows the error.
This bit is used by the following commands:
Set Pressure (^) (Pressure/Force Control axes only)
Bit 14 - Gear Type Bit
This bit is only used if the Gear Mode bit (13) is set. It determines whether this axis will be on the master axis’s Target or Actual Position. If this bit is clear, the slave is geared based on the Target Position. If this bit is set, the slave is geared based on the Actual Position. For details on gearing, see Gearing Axes.
This mode bit can apply to the following commands:
Bit 13 - Gear Mode Bit
Note: This feature is only available in RMC100 CPU firmware dated 19990625 or newer (and beta firmware dating 19980827B or newer).
This bit makes the move act in Gearing mode. When this bit is set, the Gear Type (bit 14) and Gear Master Select (bits 4-6) bits are also used. For details on gearing, see Gearing Axes.
This mode bit can apply to the following commands:
Bit 11 - Velocity Loop Bit
Note: This feature is only available in RMC100 CPU firmware dated 20030515 or newer.
This bit is used only when the Rotational bit is set in a Go (G) command (a speed control move). If this bit is cleared, the speed control will be closed loop based on position. If this bit is set, the speed control will be closed loop based on velocity. See Speed Control for more details.
Bit 10 - Superimposed Bit
Note: This feature is only available in the special ’r;SI’ RMC100 CPU firmware (e.g. 19980827SI).
This bit may be applied to the Follow Spline (f), Follow Spline Relative and Sine Move (~) commands. When this bit is set for one of these commands, the move will be superimposed on top of one of the following types of moves: Spline (started by the Follow Spline (f) command), Sine Move (started by the Sine Move (~) command), Geared move (started by a Go (G) command with the Gear Mode bit set), and Speed Control move (started by a Go (G) command with the Rotational bit set). There may never be more than two moves in progress on an axis at one time.
If this bit is cleared for the Follow Spline (f) and Sine Move (~) commands, the newly requested move is executed without being superimposed.
Bit 9 - Rotational Bit
This bit needs to be set for most applications where the axis will be rotating multiple times. Setting this bit causes the following:
The Extend and Retract Limits do not limit the motion. Instead they are used to control the wrap of the position: when the position exceeds the extend limit, the difference between the two limits is subtracted from the position, and likewise when the position exceeds the retract limit, the difference is added to the position. Generally, these limits will be set to indicate one rotation (such as 0 and 36,000 for hundredths of a degree).
The Go, Set Speed (Unsigned), and Set Speed (Signed) act in Speed Control mode, as described in the Speed Control topic.
Bit 8 - Monitor Pressure
Only axes which have pressure axes assigned to them use this bit. If this bit is set on such an axis, the pressure will be monitored to see if it reaches the minimum pressure threshold at which point the axis will begin regulating pressure. For details on using this bit to regulate pressure, refer to Controlling Pressure or Force.
Bit 7 - S-Curve
When this bit is set the RMC calculates a s-shaped target, resulting in smoother motion with more gradual starts and stops and higher peak speeds. In a s-curve move, the maximum acceleration is 1.53 times the straight-line acceleration (used by a trapezoidal motion profile). If another move command is given before the s-curve is finished, there may be a discontinuity (jerk) at the transition.
This mode bit can apply to the following commands:
Bit 4-6 - Gear Master Select (When Gear Mode bit is set)
When the Gear Mode bit (13) is set, these bits are used together to select the gear master for this axis. Refer to Gearing Axes for details on gearing. We highly recommend that you use the Pop-up Editor for the Mode word to edit this field rather than enter the value directly. However, if this is necessary, the following table shows how to select a master axis using these bits:
|
Master Axis |
Bit # |
6 |
5 |
4 |
|
Axis 0 |
|
0 |
0 |
0 |
|
Axis 1 |
|
0 |
0 |
1 |
|
Axis 2 |
|
0 |
1 |
0 |
|
Axis 3 |
|
0 |
1 |
1 |
|
Axis 4 |
|
1 |
0 |
0 |
|
Axis 5 |
|
1 |
0 |
1 |
|
Axis 6 |
|
1 |
1 |
0 |
|
Axis 7 |
|
1 |
1 |
1 |
These mode bits can apply to the following commands:
Bit 6 - Quick Mode (When Gear Mode bit is not set)
When this bit is set, a move will ramp the drive up in Open Loop Mode to the value specified (in millivolts) in the Speed field and maintain it there until it reaches the deceleration point. It will then ramp down to the requested position (specified by the Command Value) in Closed Loop Mode . The Acceleration and Deceleration fields specify the ramp based on Mode bits 0 and 1.
For this mode to work properly the Extend Feed Forward and Retract Feed Forward parameters should be adjusted correctly. They are use to calculate the drive given to the axis at the moment ramp down begins.
If the speed achieved by the axis during the open loop portion of the move is greater than 65,535, when the ramp down starts, the target speed will be limited to 65,535.
This mode bit can apply to the following commands:
Why Bother?
If the application requires quick positioning without the need to synchronize or gear with other axes, use the Quick Mode. With Quick Mode, the Drive output can be saturated for maximum speed without worrying about the PID’s integrator winding up. When the axis transitions from Open Loop Mode to Closed Loop Mode the Target Speed is set to the Actual Speed, the Target Position is set to the Actual Position and the integrator is set to zero.
Bits 4-5 - Sync Group A or B (When Gear Mode bit is not set)
These two bits are used for axis synchronization. If the Gear Mode bit is cleared, these bits select which synchronization group this axis belongs to; see Synchronizing Axes for details.
Therefore, two independent groups of axes can be synchronized using these two bits. At no time should both of these bits be set at the same time.
A side benefit is that if an error occurs that stops an axis with a sync bit on, other axes with the same sync bit set will also stop.
These mode bits can apply to the following commands:
Bits 2-3 - Integrator Mode Select
These two bits define four integrator modes:
|
Bit # |
3 |
2 |
|
Mode 0 - Integrator always active - Default |
0 |
0 |
|
Mode 1 - Integrator active only during deceleration and in position |
0 |
1 |
|
Mode 2 - Integrator active only during in position |
1 |
0 |
|
Mode 3 - Integrator never active |
1 |
1 |
Why Bother?
The integrator can be disabled so that it doesn’t wind up. This can be handy in applications where the Actual Position can’t reach the Target Position. Even-ending or clamping applications should use these bits.
Bits 0-1 - Acceleration and Deceleration Mode Select
These two bits define four acceleration/deceleration modes:
|
Bit # |
1 |
0 |
|
Mode 0 - Ramp Rate (Default) |
0 |
0 |
|
Mode 1 - Ramp Rate * 1000 |
0 |
1 |
|
Mode 2 - Distance to specified speed |
1 |
0 |
|
Mode 3 - Time to specified speed |
1 |
1 |
In Mode 0, the Acceleration and Deceleration parameters define the ramp rate in position units per second per second.
In Mode 1, the Acceleration and Deceleration parameters define the ramp rate in 1000 position units per second per second. For example, with position units of 0.001 inches, an Acceleration of 50 will cause the axis to accelerate at 50 inches per second per second.
In Mode 2, the parameters define the distance in position units to accelerate or decelerate to the specified Speed.
In Mode 3, the parameters define the time in milliseconds to accelerate or decelerate to the specified Speed.
Refer to the appropriate section in Gearing or Open Loop for details on the use of these bits in these modes.
Copyright (c) 1997-2015 by Delta Computer Systems, Inc.