Chapter 16 PLC Function ApplicationsMH300
16-2 Notes Before Using a PLC
1. The MH
300 provides two communication serial ports that you can use to download programs to
the PLC (see Figure 16-1 below).
Channel 1 (USB port) communication format is the same as channel 2.
Channel 2 has a preset communication format of 7, N, 2, 9600; you can change to ASCII in
Pr.09-01 (transmission speed) and Pr.09-04 (communication protocol).
2. The PLC preset is node 2; you can change the PLC node in Pr.09-35 (PLC address), but this
address may not be the same as the drive’s address setting in Pr.09-00 (communication
address).
Figur
e 16-1
3. The host controller can simultaneously access data from the drive and the internal PLC, using
the identifier for the node. For instance, if the drive node is 1 and the internal PLC node is 2, then
the host controller command depends on the node address:
01 (node) 03 (read) 0400 (address) 0001 (1 data item), indicating that it must read the data
in drive Pr.04-00.
02 (node) 03 (read) 0400 (address) 0001 (1 data item), indicating that it must read the data
in internal PLC X0.
4. The PLC program is disabled when uploading/downloading programs.
5. Note that when using WPR commands to write parameters, you may modify values up to a
maximum of 10
9
times; otherwise, a memory write error occurs. The number of modifications
depends on whether the parameter value has changed. If you do not change the value, it does
not change the number of modifications; however, if the entered value is different from before,
the number of modifications increases by one.
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