Yaskawa PLC-5 - Manual (Page 13)

GENERAL OPERATION
10 GENERAL OPERATION 2/17/95- RD 3196-10
GENERAL
OPERATION
The PLC gateway is normally mounted and wired on a Yaskawa drive panel.
The gateway, however, can be mounted remotely by the customer. In this case,
special consideration must be given to the 120 VAC power source for the
gateway power supply. DO NOT connect the gateway power cord directly into
a wall outlet. Instead, use an isolation transformer and tie one side of the
secondary to the nearest earth ground (the steel structure of the building is
usually a good choice). The ground studs on the MicroTrac drive panels or
cabinets must also be connected directly to a solid earth ground in order to
assure that the gateway enclosure and the drive panels are at the same potential.
Improper grounding may cause erratic operation of the LAN.
The PLC gateway, when connected to the A-B 1771 remote I/O cable, is treated
as a remote I/O rack by the PLC. From a PLC-5 the selected rack number can
be between 1 and 7 (inclusive). From a PLC-3 the rack number can be between
0 and 7. Note that the PLC gateway is configured as a rack on the remote I/O
link, and cannot be the same rack number as any other rack on the remote I/O
link. If local racks are to be used, the rack number assigned to the PLC
gateway must be greater than the last local rack number.
The baud rate of the A-B 1771 remote I/O link is determined by the PLC. A
DIP switch on the SmartMUX board selects the A-B 1771 link speed. The
acceptable baud rates are 57.6K, 115.2K, and 230.4K.
A gateway uses one entire remote rack with the following capacity:
— 64 numerics PLC to MicroTrac in group 0, slot 0.
— 64 numerics MicroTrac to PLC in group 0, slot 0.
— 8 local logics (8 inputs or 8 outputs) in group 0, slot 1.
— 112 logics PLC to MicroTrac in groups 1-7.
— 112 logics MicroTrac to PLC in groups 1-7.
CAUTION
The gateway must be properly grounded. When mounting, use star washers
that will cut into the metal of the gateway box to ensure proper earth ground.
.