Reference Manual

Turbo PMAC/PMAC2 Software Reference

Turbo PMAC On-line Command Specification 358

M{constant}->TWR:{address}

Function: Resolver Thumbwheel-Multiplexer M-Variable Definition

Scope: Global

Syntax: M{constant}[..{constant}]->TWR[:]{multiplex address},

{offset}

where:

 {constant} is an integer from 0 to 8191 representing the number of the M-variable;

 the optional second {constant} must be at least as great as the first {constant} -- it represents

the number of the end of the range;

 {multiplex address} is an integer constant, divisible by 2, in the range 0 to 254, representing

the address in the multiplexing scheme of the Acc-8D Option 7 resolver-to-digital converter board on

the thumbwheel multiplexer port, as determined by the DIP switch settings on the board

 {offset} is an integer constant from 0 to 7, representing the location of the device at the specified

multiplexer address, as determined by in the buffer on the Acc-8D Option 7 and the actual pins to

which the device was wired.

This command causes Turbo PMAC to define the specified M-variable or range of M-variables to point to

a 12-bit word from a resolver-to-digital (R/D) converter or similar device serially multiplexed on the

thumbwheel port on an Acc-8D Option 7 or compatible board.

The address on the multiplex port specified here must match the address set by the DIP switches on board

the Acc-8D Option 7. The Acc-8D Option 7 manual contains a table listing all of the possibilities.

One of the DIP switches on the Acc-8D Option 7 board determines whether the R/D converters on board

have offset values of 0 to 3 or 4 to 7. The {offset} specifier must match this DIP switch setting and

the number of the R/D device on the board.

This is a read-only M-variable format. Use of this variable in an on-line query command or a program

statement will cause Turbo PMAC to clock in 12 bits of unsigned data (range 0 to 4095) from the

specified device through the multiplexer port.

Note:

It is not necessary to use an M-variable to access an R/D converter for actual servo

or phasing feedback purposes. I-variables (Ixx10, Ixx81, Ixx98, Ixx99) are used

for that purpose. However, even if this is the only use of the R/D converter,

usually it is desirable to assign M-variables to the R/D converters for set-up and

diagnostic purposes.

Example:

M100->TWR:0,0

M99->TWR:4,5