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6.0
APPLICATIONS USING TWO OR MORE DS9000 UNITS
It is possible to construct a system of DS9000 units which will work in conjunction with each other.
By utilizing the follower capability of the unit, it can be made to produce a speed related to the speed
of another unit, which will automatically change with the master speed, staying proportional. Two
methods of multi-unit connections may be used.
6.1
PARALLEL CONNECTION
In a parallel system, one DS9000 is used in master mode to control a motor. Two or more DS9000's
programmed for follower mode may be connected to the pulse generator of the master unit's
controlled motor. Each follower then has a reference from the master. A ratio may be set on each
follower, for example, follower #1 – 90%, follower #2 – 80% . . . If the master is set for 1000 RPM,
follower #1 motor will go to 900 RPM, and follower #2 motor to 800 RPM. If the master is slowed to
800 RPM, the others will follow, motor #1 at 720 RPM, and motor #2 at 640 RPM. They each
maintain their set ratio with regard to the master. This is an ideal system for situations where multiple
motors must run at a different, yet proportional speed with regard to a master, but their speeds with
reference to each other are not important.
6.2
SERIES CONNECTION
In a series connected system, commonly known as a "Daisy chain", one DS9000 may be used in
master mode to control a motor. A second unit programmed for follower mode takes its reference
from the pulse generator on the master unit's motor. A third unit may then take its reference from the
pulse generator on the second unit's motor. In this configuration, each unit will maintain a set ratio
with regard to the previous unit in the chain. For example, follower #1 may be set for 90%, and
follower #2 for 80%. If master is set for 1000 RPM, follower #1 motor will go to 900 RPM, and
follower #2 motor will go to 720 RPM. The ratio is with regard to the previous unit, not the master.
This is an ideal system for use when a certain percent "draw" between units must be maintained as
line speed is changed.
7.0
SYSTEM TROUBLESHOOTING
In this section, we will provide guidelines to assist in restoring the DS9000 to proper operation.
7.1
ERROR CODES
The only error code that will be displayed on the readout is "OPLP". This means "open Loop" and
will be displayed in two different circumstances. When DipSW2 is in the ON position, the DS9000 is
running "Open Loop". The DS9000 is not correcting any error between the programmed speed and
actual speed but just giving a 0-10V DC signal in response to the programmed speed. The "OPLP"
display is a normal display during this mode of operation and is not considered an error code.
When using the DS9000 as a follower controller, the error code, "OPLP", indicates excessive error
between the master reference and the Follower motor feedback. This could occur if the follower
motor was either stopped or running in current limit and not able to maintain the desired speed ratio.
The error would accumulate until the "OPLP" error code is displayed. If the signal from the follower
motor feedback was lost through an open connection, then this would also cause the error code to
appear.
An output connection, TB1-7, is an open-collector output that provides the user with a signal to his
external system that a "OPLP" error has occurred. Refer to Figure 1 for correct wiring directions. A
relay coil and DC supply source can be connected between TB1-7 and circuit common (TB1-9 or 12).
TB1-7 provides a current sink when the excessive following error condition occurs. When the error
code "OPLP" is displayed, the DS9000 no longer maintains the position with the master reference, but
operates as a speed control. To reset the DS9000 to maintain position lock, temporarily remove the
Start input. When the Start input is reapplied, the DS9000 will again maintain position synchron-
ization of the follower motor with the master reference.
38
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