Am using a couple Yokogawa YPP 6200 and am looking for the pinout of the M Link connector so I can connect them to a Modbus Network.
The Yokogawa YPP6200 is a private labeled Precision Digital PD6200.
There is no published pinout for the M-Link connector. The M-Link connector is a USB port, natively used for Precision Digital's MeterView Pro configuration software. The M-Link connector does NOT have RS-232 or RS-485 functionality.
RS-232 or RS-485 functionality for Modbus communications is achieved with a Precision Digital serial adapter (or the same item labeled Yokogawa). Each adapter comes with a CAT5e cable for the M-Link connection. The adapter is DC powered through the M-Link cable. For the serial side, the 232 adapter has a DB9F connector, the 485 adapter has screw terminals. The adapters have no mounting tabs, so a DIN rail mounting (PDA1002) kit is available.
The RS-232 adapter is PDA1232; the RS-485 adapter is PD1485 from Precision Digital. I'm sure Yokogawa offers the same things.