Hardy HI 2151/30WC Single-Scale Controller - Manual (Page 105)

Chapter 7 - Operation
7-7
Step 8. If the option for 8 relays is active, enter set point parameters
for relay 3-8 at this time.
Step 9. When the last set point parameter is entered, press Exit button
to return to the weight display and resume normal operations.
Serial Communications The standard serial ports are user selectable RS-232C, and RS-422/485
which may be configured as a printer output port or as a bi-directional
communication port. Transmission speed is selectable from 600 to
19.2K baud and may be configured for a continuous data output mode.
The port allows host computer control using ASCII character com-
mands and RS 422/485 ports support multiple weight controllers via a
multidrop configuration.
Bi-directional
Communications
RS-232C One RS-232C allows serial communication from one weight controller
to one peripheral device. The RS-232C is user-selectable as a print-out-
put only port or as a bi-directional control port through the Menu and
jumper settings on the main board. (See Chapter 4 for configuration
information)
Operation The operation consists of properly executing commands over the serial
port.
RS-422/485 The RS-422/485 meet RS-422 or RS-485 requirements providing drive
over long distances. With the Hardy Link two way multidrop, commu-
nication can take place between any of the Hardy Instruments series
2100 controllers and a host computer.
Operation Operation of the RS-422/485 consist of properly configuring the board
(See Chapter 4, Section 4.1 for configuration information) and execut-
ing commands over the port. Commands available and their actions are
identical to the commands for the RS-232C.
Description of 422/
485 Transmission
Modes Available Many devices available today are called RS-422/485 because their
electrical signals meet or exceed both specifications. This does not nec-
essarily mean they both meet the strict intent of RS-485 to provide for
two wire multidrop networks. They are instead multidrop RS-422 or
four wire RS-485 networks.
RS-485 The RS-485 mode when configured as two wire (2 wire jumper) with
the transmitter enabled.
RS-422 If the unit is in the four wire (4 wire jumper) mode with the transmitter
always enabled, then the board operates in a true RS-422 mode. This
flexibility allows compatibility between the host computer and the HI
2151/30WC.