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MMC120 Linear Motion Control Module Communicating with the MMC120

Delta Computer Systems, Inc. 360/254-8688 49

Output Registers

Four 16-bit registers are sent to the MMC120 each time the I/O drop is accessed. The registers contain

commands and data:

Contents

4TTTTT + 0 Command - Axis 1

4TTTTT + 1 Data Out - Axis 1

4TTTTT + 2 Command - Axis 2

4TTTTT + 3 Data Out - Axis 2

The commands sent to the two axes are independent of each other.

Data should only be written to the module once per segment, otherwise new data overwrites previous data.

Only the last information placed in the output registers is transferred to the module.

COMMANDS

Command registers are divided into two bytes. The most significant byte (bits 1 - 8) specifies the Readback

mode; it is called the READBACK byte. The least significant byte (bits 9 - 16) specifies the instruction the

MMC120 is to follow; it is called the INSTRUCTION byte.

The two bytes in the command register are divided into 4-bit nibbles (a "nibble" is half a byte). In the

INSTRUCTION byte the most significant nibble (bits 9 - 12) specifies the Command Type; the least

significant nibble (bits 13 - 16) specifies an index indicating what the command acts on. In the Readback

byte,bits5-8aretheStatus Area Request (SAR) field indicating what status information the MMC120 is to

return,andbits1-4areusedbyplotsandEventStepcommands. (See the Input Register section.)

Command Register

READBACK INSTRUCTION

Events & Plots SAR CMD TYPE INDEX

Bit#12345678910111213141516

1 2 ... 44 45 46 47 48 49 50 51 52 53 54 ... 104 105

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Delta MMC120 Manuel d'utilisateur Page 49