SERIAL COMMUNICATIONS
38
of preset values. Before the value(s) are sent, the
control sends an identifier which indicates what
information is to follow. When the control is con-
nected to a printer, these identifiers are also
printed. The label “CNT” is printed before the value
of the counter, “PS1” is printed before the Preset 1
value, “PS2” is printed before the Preset 2 value
and “PS3” is printed before the Preset 3 value. If a
decimal point has been specified by programming
Function 62, the decimal point is inserted into the
printout at the appropriate place.
Figure 30 shows graphically how a typical value is
transmitted. Each block shown consists of the bit
organization as indicated in Figure 29.
Figure 31 shows a sample printout when the con-
trol has been set up to print both the counter and
preset values with a decimal point before the sec-
ond digit.
If the count value and both preset values are to be
transmitted, the count value is always transmitted
first, Preset 1 second, Preset 2 third, and Preset 3
last.
The control can be programmed to automatically
transmit its values when reset. This mode is
selected by entering a “1” in Function 92. Upon
pressing the “RESET” key or having the Reset
input energized, the control internally stores the
count value, then resets the counter. Once the
control is reset, the stored count value is transmit-
ted. This allows the count value to be recorded
while the process is running without losing any
counts.
Figure 31.
Typical Printout of
Transmitted Values
Figure 32.
Typical Preset Change Serially Communicated
When the Print on Reset mode is selected, the
Print Request input may be energized or the ASCII
“?” received through serial communication to
cause a printout without resetting the counter.
RECEIVING DATA
The control can receive a command through the
serial communications input which instructs it to
automatically transmit the information of the
counter or presets (depending on Function 91).
This command has the same effect as energizing
the Print Request input. The ASCII character “?”
asks the control to send its data.
In addition, the preset values can be changed
through the serial communication input when a
new value is received from a remote preset periph-
eral, a host computer or another compatible
peripheral. The new Preset 1 value must be pre-
ceded by the ASCII character “A” which informs
CNT
1234.56
PS1
5000.00
PS2
9738.15
PS3
0050.00
