Delta CT2000 Series, User Manual

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Chapter 16 PLC Function

CT2000 Series
16-147
16-12 Modbus
remote IO control applications (use MODRW)
The CT2000's internal PLC supports 485 read/write functions, which can be realized using the
MODRW command. However, the 485 serial port must be defined as available for the PLC's 485 use
before writing a program, and the parameter 09-31 must be set as -12. After completing settings, the
standard functions defined by 485 can be used to implement read/write commands at other stations.
Communications speed is defined by parameter 09-01, the communications format is defined by
parameter 09-04, and the PLC's current station number is defined by parameter 09-35. The CT2000
currently supports the functions
read coil (0x01), read input (0x02), read register (0x03), write to single register (0x06), write to
several coils (0x0F), and write to several registers (0x10). Explanations and the usage of these
functions are provided as follows:
MODRW command
General
meaning
Slave device is Delta's PLC
meaning
Slave device is Delta's
converter meaning
S1 S2 S3 S4 S5
Node
ID
Comman
d
Address
Return:
D area
Length
:
K3 H01 H500 D0 K18
Read coil
(Bit)
Read 18 bits of data corresponding to
slave station 3 PLC Y0 to Y21. This
data is stored by bit 0 to 15 of the this
station's D0 and bit 0 to bit 3 of D1.
Does not support this function
K3 H02 H400 D10 K10
Read input
(Bit)
Read 10 bits of data corresponding to
slave station 3 PLC X0 to X11. This
data is stored by bit 0 to 9 of this
station's D10.
Does not support this function
K3 H03 H600 D20 K3
Read register
(word)
Read 3 words of data corresponding
to slave station 3 PLC T0 to T2. This
data is stored by D20 to D22.
Read 3 words of data
corresponding to slave station
3 converter parameters 06-00
to 06-02. This data is stored by
D20 to D22
K3 H06 H610 D30 XX
Write to single
register (word) Write slave station 3 PLC's T16 to this
station's D30 value
Write slave station 3 converter
06 to 16 parameter to this
station's D30 value
K3 H0F H509 D40 K10
Write to
multiple coils
(Bit)
Write slave station 3 PLC's Y11 to
Y22 to bit 0 to 9 of D40.
Does not support this function
K3 H10 H602 D50 K4
Write to
multiple
registers (word)
Write slave station 3 PLC's T2 to T5 to
D50 to D53
Write slave station 3 converter
06-02 to 06-05 parameters to
this station's D50 to D53
※
XX indicates doesn't matter
After implementing MODRW, the status will be displayed in M1077 (485 read/write complete), M1078
(485 read/write error), and M1079 (485 read/write time out). M1077 is defined so as to immediately
revert to 0 after the MODRW command has been implemented. However, any of three situations—a
report of no error, a data error report, or time out with no report—will cause the status of M1077 to
change to On.
Example program: Testing of various functions
At the start, will cause the transmitted time sequence to switch to the first data unit.
0 M1002
MOV
K4M0 K1
On only for 1 scan a