PD-F1007
53
Disc No.
219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234
217 218
DCNT
DPOS
Disc No.
237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252
235 236
DCNT
DPOS
Disc No.
255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270
253 254
DCNT
DPOS
Disc No.
273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288
271 272
DCNT
DPOS
Disc No.
291 292 293 294 295 296 297 298 299 300 301 302 303 S.L
S.L (304): SINGLE LODER
305 306
289 290
DCNT
DPOS
Disc No.
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
307
1
DCNT
DPOS
1
The microcomputer looks every 1 msec at the status (H or L) of
the two inputs DCNT and DISC.
2
8 msec (A in the figure) after the drop of DCNT (C in the figure),
the last 17 DISC inputs (B in the figure) are checked.
A disc is assumed to be resent when even one of them is "L".
3
No disc is assumed when DISC was "H" all 17 times (B in the
figure) in
2
.
Note: In regard to the drop (
) of DCNT
For looking at the drop or rise of DCNT, it is necessary to check
DCNT every 1 msec for "H" or "L".
"H"
=
"L" means a drop (
).
"L"
=
"H" means a rise (
).
For the timing, either one of the following A and B can be assumed.
Accordingly, the point where a drop is found differs by max. 1 msec
for A and B.
Thus, using the above figure, it can be said that the time from
finding that a drop has occurred until starting to check for disc
presence (A in the above figure) becomes 8 to 9 msec.
Relation between input port DCNT, DPOS
and position of the mechanism
2. Position relation between position of the rack
mechanism and photocell for disc detection
The relation between these two positions is as follows.
Fig.: The rack seen from above
The position of the mechanism and the photocell for detection are
offset by a distance corresponding to 9 discs. Accordingly, the
photocell for detection sees the disc number 9 discs before the
position of the mechanism.
Example: Disc No. at the rack position
: Disc No. 100
Disc No. seen by the photocell for detection
: Disc No. 91
Note: The rack has 307 slits, but the slits 301 to 303 and 304 to 307
are the space for the side of the single loader and are not used.
Disc detection also is not performed for them.
3. Disc Detection Method
3-1 In Regard to the Disc Detection Method
Disc detection is performed after stabilization of the rotation
speed after rack rotation start and completion of acceleration.
(After start of rotation, detection starts after feed of 20 discs.)
The input ports DCNT and DISC of the microcomputer are used
for disc detection.
Port Explanation :
DCNT : As described above.
DISC : Input of the disc detection result
by the photocell for disc detection.
Input value "H" : No disc,
"L" : Disc present
3-2 In Regard to the Disc Detection Timing
C
DCNT
DISC
A
(8msec)
B
(16msec)
A
B
"H"
"L"
"H"
"L"
1msec
1msec
Photocell for detection
Position of the
mechanism
