Delta RMC101 - Manual (Page 507)

Serial (RS-232/422/485) 5.5
Communications 5-257
• Baud Rate: 19,200
• Data Bits: 8 bit
• Parity: Even
Mitsubishi PLC Settings:
The Mitsubishi PLCs use D8120 to control its communication format. Assuming the maximum baud
rate of 19,200 and even parity are used, then the following value must be used to communicate with
an RMC:
D8120 = H0097
In addition M8161 should be set as follows to select 16-bit data:
M8161 = OFF
D8120 can be broken down into the following options:
• Data Length: 8 bit (b0 = 1)
• Parity: Even (b1, b2 = 1, 1)
• Stop Bits: 1 (b3 = 0)
• Baud Rate (bps): 19,200 (b4-b7 = 1, 0, 0, 1)
• Header: None (b8 = 0)
• Terminator: None (b9 = 0)
• Control Line: None (b10-b12 = 0, 0, 0)
• Protocol: No protocol (b14 = 0)
• Bits 13 and 15 are reserved for No Protocol, and must be zero (0).
A demo program NOPROTO should be used as a starting point for any Mitsubishi FX program
using a RMC. This program is posted on the web at
http://www.deltacompsys.com/Files/rmcfx.zip.
Using the Mitsubishi-RMC Protocol
Communicating with the RMC from the Mitsubishi PLC requires two buffers in the PLC: one for
sending data and one for receiving data. Each buffer should be 100 words long. This allows for
data transfers of up to 96 words of data with a header consisting of a length and RMC address,
and a trailing checksum using the CCD instruction that actually generates two words. The parity
check result of the CCD function is the second word and is not used.
The RS function should be used to used as set the buffer addresses and the length of each
transfer. The buffer address should never change from one transfer to the next but the length will
change.
After the out going message is constructed it is sent using a RS function. This is enabled by
setting bit M8122. At this point, the RS function will send data and wait to receive the requested
number of bytes from the RMC. When both have occurred, bit M8123 will be set. At this time the