YOKOGAWA UTAdvanced Series, User Manual

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4-9
IM 05P07A01-01EN
Description of Ethernet Communication (Modbus/TCP) (for UT
Advanced with Ethernet Communication)
4

15 Writing to multiple I relays

Function
Data is written to I relays continuously for the specified number of relays from the
specified I relay No.
• The maximum number of relays that can be written at a time is 256.
• For details on the response format at an error, see “4.4.4 Response Error Codes.”
• The data to be written is one bit for each I relay.
The bit indicates: 1 = ON and 0 = OFF. The LSB of the first written data item indicates
the status of the write start I relay.
The status of 8 I relays is represented by one byte. If the maximum number of I relays
is exceeded by the last written data, the exceeding part of the data item is not written.

Request (during normal operation) Write n number of data
Element MBAP Header PDU
Number of bytes 2 2 2 1 1 2 2
Command
element
Transfer ID Protocol ID Number of
bytes
Unit ID Function code I relay start No. Number of
I relays
(Hex) Optional value 0000 N+7 01 0F n
Continuation of request
PDU
1 1 1
Byte count
(Note 1)
Data 1 • • • Data N
N
Note 1: When the byte count is assumed to be “N,” N = Number of write I relays / 8 (however, N =
N + 1 when the remainder is not zero).

Response (during normal operation)
Element MBAP Header PDU
Number of bytes 2 2 2 1 1 2 2
Command
element
Transfer ID Protocol ID Number of
bytes
Unit ID Function code I relay start No.
Number of
I relays
(Hex) Optional value 0000 0006 01 0F n
4.4 Communication with Host Computer