![Siemens MOBY I ASM 421 Technical Description Download Page 55](http://html.mh-extra.com/html/siemens/moby-i-asm-421/moby-i-asm-421_technical-description_377253055.webp)
ASM 421 Technical Description
6GT2 097-3AH00-0DA2
– 53 –
RD: 03/02
6GT2 002-0DA00
ASM 421 / V.24
Subject to change without notice!
6GT2 002-0DB00
ASM 421 / RS422
6GT2 002-0DC00
ASM 421 / TTY
J31069-D0142-U001-A0-7618
5.4
MDS control using 2 DIs
EAKO = ’3’
Schematic layout:
ÉÉ
ÉÉ
ÉÉ
a
Prox. switch
on DI 0
Direction of
movement of
MDS
MDS
Prox. switch
on DI 1
ÉÉ
ÉÉ
ÉÉ
e
Computer
or PC
ASM 421
SLG
A
E
Transmission window; no significance for
entry/exit monitoring
Entry (E) of an MDS is detected by a proximity switch connected to DI 0. The MDS does not have to be
within the transmission window of the SLG at this time. Command processing begins as soon as the MDS
enters the transmission window. The MDS can move anywhere between points A and E without causing
an error. When the MDS reaches point A (exit), the ASM 421 receives an impulse via DI 1. The ANW bit is
reset. The MDS has passed the Exit.
e, a: The distances from the SLG to the entry and exit proximity switches can largely be chosen at will by
the user. Note, however, that two MDSs can never be between points E and A at the same time.
After processing each MDS, it is imperative that the user sends a NEXT command. The file handler as-
sumes complete and continuous control of the MDS. An error will be reported if:
– the MDS is defective
– two MDSs in succession have passed point E (or the same MDS twice)
– two MDSs in succession have passed point A (or the same MDS twice)
– if no NEXT command is issued following an E-A sequence
Note:
After a RESET, the presence of an MDS will only be detected (ANW bit = 1) if it is already within the trans-
mission window of the SLG!