SMAC
LAC-26 Technical Reference Manual
4/29/2013 12
During interrupts and macro calls, the axis number is saved and then later restored.
After an
interrupt macro entered or a macro call is taken, it is a good idea for the user to make sure an axis
number (if necessary) gets set during one of the first commands encountered.
The numerical range of an argument will vary depending on the command with which it is used.
The mathematical interpretation of the argument will depend on whether the Decimal Mode (DM) or
Hexadecimal Mode (HM) was the last issued (DM is the power on default). Both decimal and hexadecimal
numbers less than zero should be entered with a preceding minus "-" sign. If no argument is given, then it
will be assumed as "0". The exceptions to this are the Macro Define (MD), Macro Jump (MJ), Macro Call
(MC),Macro Sequence (MS), Reset Macro (RM) and Tell Macro (TM), commands. It should be noted that
commands can be strung together by using commas, up to a maximum line length of 127 characters.
If a command line is ended by a ";" and a comment, i.e...
>SG1000,SD5000 ; Set filter gains.<CR>
then the ";" and anything following it to the end of the line will be ignored. This feature is not particularly
useful if you are entering commands manually, as comments are not retained by the LAC-26. However, if
commands are downloaded to the LAC-26 from a host computer, the ability for line comments can make
program documentation possible and desirable.
3.1 Downloading Commands
In many cases, it is more convenient to enter commands using a text editor on a host computer
and then download that text file to the LAC-26 using a communications program such as ProComm or the
Microsoft Windows Terminal program. Whatever communications software is used, it must have the
ability to provide a short delay (approx. 100 mS) after transmitting each line to give the LAC-26 time to
interpret and store the commands that were just sent.
4. Introduction to Commands
The LAC-26 command instructions are varied and consist of several categories of purpose. The
command descriptions will be detailed by these categories.
4.1 Parameter Commands
The parameter setting commands are considered to be those for setting the operating conditions
of the servo system (i.e. PID filter gains, velocity, acceleration and etc.).
Command:
aDBn -- Dead-Band --
Argument:
0 <= n <= 16383
Default:
0
This command sets the position following error dead-band for servo axis 'a'. The purpose for the
DB command is to allow an acceptable static position error for which there will be no restoring force. This
has the affect of reducing or eliminating "hunting" which is the continuous movement at or about a
position in trying to seek that position. This is useful for applications that cannot tolerate this condition.
Please note that the DB command is only in effect when the servo is not in motion (or when the Trajectory
Complete bit is set in the servo status word).
Related Commands: TF
