Delta MMC120 User Manual download pdf (Page 22)

Startup MMC120 Linear Motion Control Module

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

STARTUP

CAUTION: Do not connect the drive outputs to the drives until the EXTEND and RETRACT limits have been

determined and the MMC120 has been properly initialized with these limits by the Quantum

Programmable Controller.

Great care must be taken to avoid accidents when starting the Motion Control Module for the first time.

The most common accident is a runaway, where the motion controller tries to go to a position beyond the

physical limits of an axis.

When the MMC120 Motion Control Module is first turned on the parameters are set to default values. These

values allow the module to maintain the present positions of the axes it controls; the parameters must be

changed for the module to work in your system. The Quantum Programmable Controller program is

responsible for initializing the parameters when the MMC120 is powered up by sending the correct

initialization parameters to the module, then issuing a 'P' command. The following procedure will help find

the optimum values for the initialization parameters.

TIP: Use Delta's DCS120 setup program to help determine initial parameters and operation. Also, Delta's SSS/10

Servo System Simulator and PPS/14 Position/Pressure Simulator provide a simple way to test your program

before connecting the module to a real system. See APPENDIX A: DCS120 DIAGNOSTIC AND SETUP

PROGRAM.

Configure DCS120 to communicate with the module. Make sure the transducers are connected and powered

up. Disconnect the drive output from the MMC120 (3 pin connector), and arrange a way to manually move

the axis, either physically or with a control box that can electrically drive the valve (a 'diddle box'). If neither

of these options are usable to you, the procedure shown in 'Moving the Axis' (pages 21 and 22) uses DCS120

and the Open Loop mode to slowly move the axis.

Initialization Parameters

If you want to get started quickly, go to the next section - Moving The Axis. Continue with this section now

or return to it later to set the SCALE and OFFSET parameters.

The easiest way to set the SCALE and OFFSET is to use the P0 and P1 commands in DCS120. To use these

commands, you need to know the physical position and the corresponding transducer counts at two points

(usually the extend and retract limits). For example, if the first position is 0.000 inches and the counts are

2163, and the second position is 27.500 inches and the counts are 31626, then enter:

P0 0 2163 <ENTER>

P1 27500 31626 <ENTER>

After you enter values for both P0 and P1, the SCALE and OFFSET fields will be updated on the screen

(notice the parameters turn gray). Use the alt-P command to activate the new values. See Appendix A for

more information about the P0 and P1 commands.

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Delta MMC120 User Manual Page 22