Inconsecutive registers can be read in a batch in one communication between Mitsubishi Electric FA and a MELSEC device by setting a value larger than the number of registers between the tags to be monitored for "Merge gap".
Reading inconsecutive registers in a batch reduces the number of the frequency of the communication (of the communication frequency). It may increase the communication speed.
If the number of registers between tags exceeds a value set for "Merge gap", inconsecutive registers are read in multiple communications.
Example:
When monitoring tags for which the inconsecutive registers are set: The registers set for a tag to be monitored: D20 to D50, D60 to D100, D200 to D300
a Registers between tags to be monitored: D51 to D59 (9 points)
b Registers between tags to be monitored: D101 to D199 (99 points)
c Registers between tags to be monitored: D101 to D199 (99 points)
Merge Gap Example
When setting '9' for "Merge gap"
D20 to D100 can be read in a batch in one communication because the number of registers for 'b' does not exceed a value set for "Merge gap". D60 to D100 and D200 to D300 cannot be read in a batch in one communication because the number of registers for 'c' exceeds a value set for "Merge gap". Therefore, D20 to D100 are read in a batch in one communication, and D200 to D300 in the next communication.
When setting '100' for "Merge gap"
D20 to D100 can be read in a batch in one communication because the number of registers for 'b' does not exceed a value set for "Merge gap". D60 to D300 can be read in a batch in one communication because the number of registers for 'c' does not exceed a value set for "Merge gap". Therefore, D20 to D300 are read in a batch in one communication.
Precautions:
If setting a value larger than the number of registers between tags for "Merge gap" when the number of tags to be monitored is small, the communication speed will be decreased because registers that are not to be monitored are also read.
Depending on a protocol to be used, the size of registers that can be read in one communication may be small.
In this case, the communication speed is decreased because registers must be read in multiple communications.