Yaskawa Microtrac Gateway to Square D Sy/MAX Family of PLCs for use with Microtrac LAN User Manual
Page 12
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4/12/94
4
OPERATION
Suggested PLC Ladder Strategy for GETN and RDCI PAC Blocks
Rung #
LOAD_PLC
LOAD_PLC
LL
LL
LL
TMR
LOAD LATCH
2 SECOND
HANDSHAKE
TIMEOUT
LOAD
UNLATCH
SET
RESET
1
2
3
4
5
6
MOVE
FROM: DSD2PLC
TO: PLC2DSD
WRITE
FROM: PLC2DSD
TO: DSD_INT
MOVE
FROM: PLC_DATA
TO: PLC2DSD
(U)
(L)
COMPARE
DSD2PLC=PLC2DSD
LL
TIMER
2 SEC
TMR
-( )-
Figure 6.
Suggested PLC Ladder Strategy for GETN and RDCI PAC Blocks
DESIGNATOR
DESCRIPTION
DSD2PLC
This numeric data is the confirmation from the DSD drive to the PLC of the parameter value
set in the drive.
DSD INT
Interface to the DSD drive system.
Load Latch. The ON state of this bit starts the two second handshake timeout timer (TMR).
LL
The OFF state of this bit resets TMR and permits the handshake transfer of data received
from the DSD drive (DSD2PLC) to data returned to the DSD drive (PLC2DSD).
LOAD_PLC
The momentary ON state of this bit initializes the transfer of a numeric value from a PLC
register (PLC_DATA) to the DSD drive.
PLC2DSD
This is the data sent to the DSD drive from the PLC. It can be either the confirmation of the
values received m(DSD2PLC) or, if the load PLC bit is ON, it can be the PLC DATA register
which is to be loaded.
PLC_DATA
This numeric data register is a store of the value pending to be transferred to the DSD drive.
This is the two second handshake timeout timer. The ON state of this bit indicates that the LL
bit had been ON for more than two seconds without receiving confirmation of a successful load.
TMR
of data from the PLC to the DSD drive. It resets the LL which in turn resets the TMR rung.
Therefore, the TMR two second handshake time out bit is a one scan pulse which may be used
to indicate a communication fault.
Table 4. GETN and RDCI Ladder Strategy Designator Descriptions
RD 914-10