LM628, LM629

SNVS781C – JUNE 1999 – REVISED MARCH 2013

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LPES COMMAND: LOAD POSITION ERROR FOR STOPPING

Command Code: 1A Hex

Data Bytes: Two

Data Range: 0000 to 7FFF Hex

Executable During Motion: Yes

Instruction LPES is essentially the same as command LPEI above, but adds the feature of turning off the motor

upon detecting excessive position error. The motor drive is not actually switched off, it is set to half-scale, the

offset-binary code for zero. As with command LPEI, bit 5 of the status byte is also set to logic high. The first byte

of threshold data written with command LPES is the more significant. The user can have the LM628 interrupt the

host to signify that an excessive position error has occurred. See the descriptions for commands MSKI and RSTI.

SBPA COMMAND:

Command Code: 20 Hex

Data Bytes: Four

Data Range: C0000000 to 3FFFFFFF Hex

Executable During Motion: Yes

This command enables the user to set a breakpoint in terms of absolute position. Bit 6 of the status byte is set to

logic high when the breakpoint position is reached. This condition is useful for signaling trajectory and/or filter

parameter updates. The user can also arrange to have the LM628 interrupt the host to signify that a breakpoint

position has been reached. See the descriptions for commands MSKI and RSTI.

SBPR COMMAND:

Command Code: 21 Hex

Data Bytes: Four

Data Range: See Text

Executable During Motion: Yes

This command enables the user to set a breakpoint in terms of relative position. As with command SBPA, bit 6 of

the status byte is set to logic high when the breakpoint position (relative to the current commanded target

position) is reached. The relative breakpoint input value must be such that when this value is added to the target

position the result remains within the absolute position range of the system (C0000000 to 3FFFFFFF hex). This

condition is useful for signaling trajectory and/or filter parameter updates. The user can also arrange to have the

LM628 interrupt the host to signify that a breakpoint position has been reached. See the descriptions for

commands MSKI and RSTI.

MSKI COMMAND: MASK INTERRUPTS

Command Code: 1C Hex

Data Bytes: Two

Data Range: See Text

Executable During Motion: Yes

The MSKI command lets the user determine which potential interrupt condition(s) will interrupt the host. Bits 1

through 6 of the status byte are indicators of the six conditions which are candidates for host interrupt(s). When

interrupted, the host then reads the status byte to learn which condition(s) occurred. Note that the MSKI

command is immediately followed by two data bytes. Bits 1 through 6 of the second (less significant) byte written

determine the masked/unmasked status of each potential interrupt. Any zero(s) in this 6-bit field will mask the

corresponding interrupt(s); any one(s) enable the interrupt(s). Other bits comprising the two bytes have no effect.

The mask controls only the host interrupt process; reading the status byte will still reflect the actual conditions

independent of the mask byte. See Table 3.

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