Gemini GV6K and Gemini GT6K Programmer's Guide

Implementing Ratio Following
This section covers the basic elements of implementing Ratio Following:
• Applying Following setup parameters
• Move profiles
• Performing phase shifts (FSHFC and FSHFD)
• Geared advanced (FGADV)
• Application scenarios:
- Electronic gearbox
- Trackball
Ratio Following Setup Parameters
Prior to executing a Following move, there are several setup parameters that must be
specified. These parameters may be established:
Programming
examples — see
application examples
later in this chapter.
• Define the master and follower (FOLMAS)
• Define master & follower scaling factors (SCLMAS, SCLA, SCLD, and SCLV) – if required
• Define the follower-to-master Following ratio (FOLRN and FOLRD)
• Define the master distance (FOLMD) – define scaling first
• Enable the Following Mode (FOLEN)
Following Status
(see TFSF, TFS and FS
commands)
Following Status bits 5-8 (see table below) are meant to indicate the status required for
Following motion (i.e., a master must be assigned, Following must be enabled, the master must
be moving, and for many features, the master direction must be positive).
Bits 7-8 represent master motion and master direction respectively. Unless the master is a
commanded position of another axis, it is likely that minor vibration of the master will cause
these bits to toggle on and off, even if the master is nominally “at rest”. These bits are meant
primarily as a quick diagnosis for the absence of master motion, or master motion in the wrong
direction. Many features require positive master counting to work properly.
Bit # Function (yes = 1; no = Ø)
5 FOLMAS Active ................A master is specified with the FOLMAS command.
6 FOLEN Active ..................Following has been enabled with the FOLEN command.
7 Master is Moving.............The specified master is currently in motion.
8 Master Dir Neg................The current master direction is negative. (bit must be cleared to
allow Following move in preset mode–MCØ).
Define the Master
and Follower;
(FOLMAS)
The FOLMAS command defines the masters and the followers. The command syntax is:
Follower
Axis
FOLMAS
Format for master assignment to follower:
Sign Bit
Master source axis # (optional)
Master source selection
170 Gem6K Series Programmer’s Guide