TMC 188/40 Motion Control Module
Motion Control Parameters
Delta Computer Systems, Inc. 360/254-8688
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Motion Control Parameters
The motion control parameters let you control an axis. You need a complete understanding of the
parameters and status bits to fully utilize the TMC 188/40's features.
Read Only Parameters (VREAD)
COMMAND POSITION
The COMMAND POSITION is the REQUESTED POSITION with limit checking applied. That is, if the
REQUESTED POSITION is outside the RETRACT or EXTEND LIMIT, the COMMAND POSITION
will be set to the value of the limit, and the axis will go to the limit. The COMMAND POSITION is
updated using the COMMAND parameter when a 'G
' (Go) or „P‟ (Initialize) command is issued.
TARGET POSITION
The TARGET POSITION is the calculated instantaneous position of the axis. When the axis is
moving the TARGET POSITION is updated every two milliseconds as it moves toward the
COMMAND POSITION. When an axis is stopped the TARGET POSITION will be the same as the
COMMAND POSITION unless an error has occurred.
TRANSDUCER COUNTS
TRANSDUCER COUNTS is the axis position read directly from the transducer counters with no
scaling.
ACTUAL POSITION
The ACTUAL POSITION is the measured position of the axis, updated every two milliseconds. The
ACTUAL POSITION is calculated from the TRANSDUCER COUNTS with the following formula:
TRANSDUCER COUNTS x SCALE
ACTUAL POSITION =
XOR DIR OFFSET
32768
If the quadrature encoder (Q option) is installed, the ACTUAL POSITION is calculated using a
different formula. Please refer Appendix C for more information.
AXIS STATUS WORD
The axis STATUS word contains 16 bits of information about the status of the axis. You can use six
error bits (2, 3, 4, 7, 8, and 10) to trigger a halt or emergency stop of the axis when in Position or
Speed modes. In Pressure or Home modes, the errors can only trigger an emergency stop.
BIT DESCRIPTIONS (See map on page 26)
Bits 2 through 5, 8, 10, and 14 through 16 are cleared whenever a 'G' command is given.
NOTE:
Bit 1 is the Most Significant Bit, Bit 16 is the Least Significant Bit.
Bit 16 - AT COMMAND POSITION
This bit will be set when the difference between the ACTUAL POSITION and COMMAND
POSITION is less than the value in the AT COMMAND POSITION field and the TARGET
POSITION equals the COMMAND POSITION. This bit is latched and only cleared by a 'G'
command
.
NOTE:
This bit will not be set if the axis halts outside the AT COMMAND POSITION window.
Bit 15 - NEAR COMMAND POSITION
