Instruction Manual

Logic Functions - Book 1
APPENDIX B - MODBUS MASTER CONFIGURATION
B-13
B.3.4 Read Input Register
The configuration of a Modbus Master EX block used to read the Input Register (Read Only
memory) area 30001 to 39999 is defined as:
INPUT1 RIR,MM,PORTz Local ASCII CFG ONLY
Not writeable through message handler.
INPUT2 NUMBER READ ATTRIBUTES Local Count CFG ONLY
Not writeable through message handler.
This value is the number of attribute values that should be read and stored at
this block’s INPUT11 through INPUTn. The minimum value is 1. The
maximum value is dependent on the number of attributes that can be read
from 125 registers.
INPUT3 STATUS INFO Local Long State
Not writeable through message handler.
See Message STATUS INFO values and descriptions above.
INPUT4 MESSAGE QUALITY Local Discrete
Not writeable through message handler.
GOOD (0) if a valid response message was received.
BAD (1) if a valid response message was not received.
INPUT5 MESSAGE ACTIVE Local Discrete
Not writeable through message handler.
Specifies whether the message transaction has been completed. The value
will be set to 1 (TRUE) when the message is triggered and remains set until
the transaction is complete or until failure is determined.
INPUT6 RESERVED Local Long State
Not writeable through message handler.
IF REFRESH STATE = 0
Previous send input value. Used in detecting low->high trip transaction.
ELSE IF REFRESH STATE = 255
This value is not used.
ELSE IF REFRESH STATE = 1 through 254
This value will get set equal to the REFRESH STATE value and decrement
by 1 each time this block executes. When it gets to 0 the read message is
sent to the slave. This value will remain at 0 until a response message is
received or the message times out. It will then repeat the cycle again.