Inovance MD520 Series - Page 223

MD‑SI‑DP1 Communication
‑222‑
Symptom
Solution
After the
connection is
successful, all
indicators on
the PLC are
green, but
data cannot
be written
into or read
from the AC
drive.
No data can be
written/read.
Check whether the operated address is correct. No
matter whether the PPO type used contains the PKW
area, the address for the read and write operations is
located in the second row (also the last row). For
example, if the I address and Q address in the last
row of the station are both 520 to 531 (note that the I
and Q addresses may start from different numbers),
the PZD1 and PZD2 data written into the AC drive are
stored in QW520 and QW522, respectively. (If the PLC
is S7‑300 or S7‑400, PQW is required.) If SFC15 is
used, check whether RET_VAL of the SFC15 block is
0. If not, an invocation error exists. Eliminate this
error first and invoke the block again. For details, see
section "8.7.4 Performing Periodic Read/Write
Operations on the AC Drive Slave".
PZD3 or
subsequent data
can be written, but
PZD1 or PZD2
cannot be written/
read.
Check that F0‑02 is set to 2 and F0‑03 is set to 9.
Check whether the command reference is in the
range of 1 to 7 (not bit) or frequency reference is in
the range of –F0‑10 to +F0‑10. If not, the write
operation fails. Check whether FE‑00 is set to U3‑17
and FE‑01 is set to U3‑16. If not, manually correct the
parameter values or restore to factory settings.
PZD1 and PZD2
can be written/
read, while PZD3
or subsequent
data cannot be
written/read.
Check whether the PPO type supports the PZD. Check
whether Device-specific parameters are set
correctly.
‑
Check the logic relations. Check whether the same
PZD is assigned with values for multiple times in a
certain logic relation (check whether the value given
by the PLC is correct under the logic relation in the
monitoring table of the PLC).
After communication is
established, the AC drive reports
ERR164, which cannot be cleared.
However, the indicators on the
MD‑SI‑DP1 expansion card and the
BF indicator on the PLC are
normal.
Check whether the high‑order 8 bits of the PZD1 data
(QW data) written into the AC drive are 0 in the PLC
program. If not, change them to 0. The PZD1
command in this user guide refers to values instead
of bits.
Note that this solution applies to MD520 only. For
other AC drives, consult the technical personnel.