Connecting the ma-21 in a current loop – Westermo MA-21 User Manual
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6021-2002
Connecting the MA-21 in a current loop
4
3
4
3
RD
2
1
2
1
4
3
2
1
TD
TD
TD
S1: 1, 5, 7, 8 on
S2: 1, 3 on
S3: 3–6 on
S4: 3–6 on
S1: 1, 5, 7, 8 on
S2: 1, 3 on
S3: 1, 2 on
S4: 1, 2 on
RD
RD
Functional description
The TD led flashes on the master when transmitting from it. The RD led flashes
on the slaves. When transmitting from a slave the TD led flashes only on that unit.
The RD led flashes only on the master modem.
Functional description
When transmitting from the master, RD and TD flash. RD flashes on the slaves.
When transmitting from a slave both RD and TD flash. On the other slaves and the
master RD flashes.
Full duplex transmission
4
3
4
3
RD
2
1
2
1
4
3
2
1
TD
Slave
Slave
Slave
Slave
TD
TD
S1: 1, 5, 7, 8 on
S2: 1, 3 on
S3: 1, 2 on
S4: 3–6 on
S1: 1, 5, 7, 8 on
S2: 1, 3 on
S3: 1, 2 on
S4: 1, 2 on
RD
RD
Half duplex transmission