Specifications

7. Application Instructions
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7-43
Special
register
Function Explanation
D1038
Data response delay time setting when PLC MPU is
slave. Time definition (0.1ms)
D1050~D1055
PLC will convert ASCII data of D1070~D1085 to HEX
and save hexadecimal data to D1050~D1055.
D1070~D1085
Built-in RS-485 communication convenience
command. This command will execute “ send”
command and receiver will return messages when it
receives. These messages will be saved at
D1070~D1085. User can check return data by viewing
the register content.
D1089~D1099
It is PLC built-in RS-485 communication convenience
command. The message that sent when this
command is executed will be saved in D1089~D1099.
Users can check by viewing the register.
D1120
Please refer to following chart for RS-485
communication protocol.
D1121
Communication address of PLC MPU when PLC MPU
is slave.
D1122 Remainder words of delivery data.
D1123 Remainder words of receive data.
D1124
Start word definition (STX). Please refer to chart
above.
D1125
The first end word definition. (ETX1) Please refer to
chart above.
D1126
The second end word definition. (ETX1) Please refer
to chart above.
D1129
Communication time out is abnormal. Time unit (ms).
It is used to set time of time out. if it is 0, it means
there is no time out. PLC will set M1129 to be ON if
receiving time of the first word or between any two
words is more than setting after executing RS /
MODRD / MODWR / FWD / REV / STOP / RDST /
RSTEF / MODRW commands to enter received mode.
Please pay attention to clear M1129 after handling.
Special
register
Function Explanation
D1130 MODBUS return fault code record.
D1256~D1295
Built-in RS-485 communication convenience
command MODRW. The command characters sent
when this command is executed will be saved in
D1256~D1295. User can check with the content of
these registers. (Users only can use MOV, DMOV,
BMOV to move the data in this area in version V4.9)
D1296~D1311
PLC will convert ASCII data in the register that user
requests to hexadecimal. (Users only can use MOV,
DMOV, BMOV to move the data in this area in version
V4.9)
Ϩʳ D1120: RS-485 communication protocol. Please refer to following chart
to set.
Content 0 1
b0 Data length 7 8
00 : None
01 : Odd
b1
b2
Parity bits
11 : Even
b3 stop bits 1 bit 2 bit
0011 (H3)
:
300
0100 (H4) : 600
0101 (H5) : 1200
0110 (H6) : 2400
0111 (H7) : 4800
1000 (H8) : 9600
1001 (H9) : 19200
1010 (HA) : 38400
1011 (HB) : 57600 (only for EH series)
b4
b5
b6
b7
1100 (HC) : 115200 (only for EH series)