MELSECQ Driver Parameters
- Last UpdatedAug 04, 2025
- 2 minute read
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UNINTENDED EQUIPMENT OPERATION Do not change these protocol parameters, except on the advice of Technical Support for this product. Failure to follow these instructions can result in death, serious injury, or equipment damage. |
Note: Always seek the advice of Technical Support personnel for this product regarding undocumented features.
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MELSECQ Parameter |
Description |
Allowable Values |
Default Value |
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Block |
A value (bytes) used by the I/O server to determine if two or more packets can be blocked into one data request before being sent to the I/O device. For example, if you set the value to 10, and the I/O server receives two simultaneous data requests - one for byte 3, and another for byte 8 - the two requests will be blocked into a single physical data request packet. This single request packet is then sent to the I/O Device, saving on bandwidth and processing. |
5 to 256 |
256 |
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Delay |
The period (in milliseconds) to wait between receiving a response and sending the next command. |
0 to 300 (milliseconds) |
0 |
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MaxPending |
The maximum number of pending commands that the driver holds ready for immediate execution. |
1 to 32 |
1 |
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PollTime |
The interrupt or polling service time (in milliseconds). Setting the polling time to 0 puts the driver in interrupt mode. |
0 to 300 (milliseconds) |
0 |
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Retry |
The number of times to retry a command after a timeout. |
0 to 8 |
2 |
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Timeout |
Specifies how many milliseconds to wait for a response before displaying an error message. |
0 to 32 000 (milliseconds) |
10000 milliseconds (Mitsubishi recommends this value) |
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WatchTime |
The frequency (in seconds) that the driver uses to check the communications link to the I/O Device. |
0 to 128 (seconds) |
30 seconds Note: This value should be increased to lower CPU load. Mitsubishi recommends a default value of 3. |