• The INHIBIT input allows you to connect a keylock or
jumper in order to disable function #41, which lets you
inhibit or uninhibit any or all functions.
• CONNECT A SERIAL PRINTER
The PC100 has terminals for serial input and output. The
type of signal is a 20 mA data loop. The serial output can be
used to transmit data to a serial printer. The input-output
is used to connect a process controller for two way serial
communication (transmit and receive.)
Commercial serial printers can be connected to the
PC100 to receive and print flow information at the end or
start of a batch or on command.
The connection to the PC100 requires that the printer be
able to receive a 20 mA serial data loop or that a current to
serial converter be used.
Always use twisted pair shielded cable for all serial
communications. Keep cable as short as possible and do not
place near power wires.
Function #66 may have to be programmed to the appro-
priate line print delay for the printer in use.
• CONNECT A CONTROLLER
The two way serial communication ports allow you to
connect the PC100 to a process controller to send and
receive data.
The connection requires that the host controller be able
to accept a 20 mA data input. Otherwise, a 20 mA to RS signal
converter must be used.
To connect more than one PC100 in series, first connect
the 20 mA to RS transformer to the serial input of the
computer. Then, connect the serial output to the first PC100
as shown. Thereafter, connect the serial output of one
9
PC100 to the serial input of the next unit.
Serial connection will be interrupted to all units if the
power supply fails on any one of the PC100s. To prevent this
from happening, you may want to connect a communications
relay to each unit.
Wiring diagrams on how to connect the relay will be found
in the relay packaging.
Up to 99 PC100s can be connected in this manner. Each
unit sending and receiving information must be identified
with an ID number. (See page15.)
The information below shows the parameters that can be
reprogrammed by a host controller as “Information Re-
ceived” and the parameters that the PC100 will transmit on
print or interrogation as “Information Sent”
Information Received Information Sent
P = Fixed Prewarn Prewarn Setpoint
B = Batch Preset Batch Setpoint
C = Cycle Preset Cycle Setpoint
H = Rate High Setpoint Rate High Setpoint
L = Rate Low Setpoint Rate Low Setpoint
I = Print (Interrogate) Scale Factor
F = Scale Factor Totalizer Count
X = Stop Batch Count
R = Resume Cycle Count
S = Start Flow Rate
V = Parameters That Vary (Counters and Flow Rate)
• SERIAL COMMUNICATION CHARACTERISTICS
• Even parity transmission with no check for parity.
• On ID mode all characters are echoed and all lines
must start with ID #. (ID number of PC100 to be
interrogated.) Example: To change the batch from
150 to 180 on unit #3, you have to transmit #3B180*.
• When not on ID mode, characters are not echoed. All
lines to start with line initial. Example: To change
prewarn setpoint from 10 to 15, transmit P15*.
• If a line is accepted by the PC100, the * sign is changed
to @. However, if a wrong line is sent to the PC100, an
“INVALID REQUEST” message will be transmitted
along with the unit ID #. If a wrong value is sent, such
as prewarn larger than batch, a “VALUE ERROR”
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