YOKOGAWA UTAdvanced Series, User Manual

Page: 41 / 866

3-10
IM 05P07A01-01EN

01 Reading multiple I relays

Function
The content of I relays is read continuously for the specified number of relays from the
specified I relay No.
• The maximum number of relays that can be read at a time is 256.
• For details on the response format at an error, see “● Response in an error state” in
“3.1.3 Configuration of Responses (response from UTAdvanced).”
• The response status of I relays is one bit for each I relay.
The bit indicates: 1 = ON and 0 = OFF. The LSB (least significant bit) of the first data
item indicates the status of the read start I relay.
If the status of I relay Nos. 20 to 27 is assumed to be ON-ON-OFF-OFF-ON-OFF-ON-
OFF, it is expressed as 01010011 (0x53) in the binary number.
The status of eight I relays is represented by one byte. If the number of I relays is
short of eight I relays in the last data item, the remaining empty space is filled with
zero.

Message (during normal operation)
Element
Message
start mark
(:)
Address No.
(ADR)
Function code
(0x01)
I relay
start No.
Number
of read I
relays
Error
check
Message
end mark
(CR+LF)
Number of bytes in RTU mode None 1 1 2 2 2 None
Number of bytes in ASCII
mode
1 2 2 4 4 2 2

Response (during normal operation)
Element
Message
start mark
(:)
Address No.
(ADR)
Function code
(0x01)
Byte count
(Note 1)
I relay content • • •
Number of bytes in RTU mode None 1 1 1 1 • • •
Number of bytes in ASCII
mode
1 2 2 2 2 • • •
Continuation of response
I relay content
Error
check
Message
end mark
(CR+LF)
1 2 None
2 2 2
Note 1: When the byte count is assumed to be “N,” N = Number of read I relays / 8 (however, N = N
+ 1 when the remainder is not zero).
3.1 Modbus Communication