Plotter displays: TRANS ERROR = B (buffer overflow) error message.
Plotter displays: TRANS ERROR = B (buffer overflow) error message.
A. Handshaking is an RS-232C communication protocol used to control data
flow between a host and the plotter based on availability of buffer
space. An overflow would occur if the plotter attempted to receive
data from the host computer while it was still trying to process
previous data, and the plotter had no place to store the incoming data.
B. Improper handshaking can cause the plotter to receive a Trans Error B
error.
C. Types of Serial Handshaking:
1. Hardware Handshaking (Direct Control):
a. Uses a positive or negative voltage applied to a hardware
line (usually CTS) in the serial cable to start or stop
data flow between the plotter and the computer.
b. Hardware handshaking is referred to Direct Control on the
plotters handshaking menu.
c. It is the most reliable form of handshake.
2. Xon/Xoff Handshaking:
a. A coded response from the plotter to the host computer via
the serial cable data line used to control data flow.
Xon = send more data
Xoff = do not send more data
3. Ack/Nak Handshaking:
a. A coded response from the plotter to the host sent via the
serial cable data line to control data flow between the
plotter and the host computer.
Ack = Data received from host was received
(acknowledged).
Nak = Data received from the host has an error, send the
data again
Ack/Nak is rarely used in today's environment.
D. If the plotter displays a Trans Error = B (buffer overflow) error,
check what the software is using: Xon/Xoff, hardware, or Ack/Nak handshaking.
1. If connected on a network, the network file server is performing
the handshaking.
2. If using a software spooler (e.g., AutoPlot, Concurrent Plot,
Spool-it), then the spooler is performing the handshaking.
3. If using a Windows-based driver, then Windows is performing of
the handshaking.
4. If plotting directly from AutoCad, the information is readily
available in the AutoCad Plotter Configuration Menu.
5. If unable to determine what handshaking the software application
is using, then contact the software vendor.
6. Whenever possible, use hardware handshake. Other forms of
handshake such as Xon/Xoff can lose data.
7. On a DOS-based system, hardware handshake using DOS I/O is the
best way to ensure a good I/O transmission. If the software
application provides the option for plotting to a file, perform
the following:
a. First issue a DOS MODE command to establish the baud rate,
parity, number of bits, and number of stop bits. The
handshake is always direct control (hardware handshake)
when using DOS.
i. The DOS MODE command format is:
MODE com_port:Baud_rate,Parity,Data_bits,Stop_bits,P
where parity is one of the following: (E = even, O =
odd, N = none)
The last character of the MODE statement (i.e., the
letter P), tells DOS to perform retries.
ii. If using COM port 1 at 9600 baud, No parity, 8 data
bits, and 1 stop bit, issue the following DOS MODE
command at the DOS prompt:
MODE COM1:9600,N,8,1,P
iii. If using COM port 2 at 9600 baud, No parity, 8 data
bits, and 1 stop bit, issue the following DOS MODE
command at the DOS prompt:
MODE COM2:9600,N,8,1,P
b. In the application, select the option for plot to a file.
The file name is to be set to the name of the COM port
being used (e.g., COM1 or COM2).
E. When the software handshake method has been determined, set the plotter
to match. To access the handshaking menu on the plotter, perform the
following:
1. Turn the plotter power on.
2. Load and size the media.
3. Place the plotter off-line by pressing the AUTO/MANUAL key.
4. Press the SETUP key.
5. Press the key marked 7 (numeral 7).
6. Press the ENTER key.
7. The plotter will display:
Host Setup Number:
Press NEXT for MENU:
8. Press the key marked 6 (numeral 6).
9. Press the ENTER key.
10. The plotter will display:
Direct Control: Y/N ?
XON/XOFF: Y/N ?
11. This is the handshaking menu. This value must be set to match
what the software requires. Direct Control is also referred to
as: hardware, hardwire, CTS, or DTR/RTS. Regardless of the
setting used, ensure that dip switches 2, 4, and 5 on the back of
the plotter are set to ON = 1. Turn all other dip switches OFF =
0.
a. To configure for hardware handshake on the plotter, press
the ENTER key to set Direct Control to equal YES.
b. To configure for XON/XOFF handshake on the plotter, press
the CLEAR/NO key to bring the cursor down to the bottom
line and press the ENTER key to set XON/XOFF to equal YES.
IMPORTANT NOTE: Older 104X Series plotters needed upgraded
ROM packs to properly use XON/XOFF. Use Hardware
handshaking (direct control) whenever possible. If the
software application only offers Xon/Xoff handshake and the
Trans Error B error message occurs, then confirm that the
ROM pack is the correct revision.
c. To configure for ACK/NAK handshake on the plotter, press
the CLEAR/NO key twice.
F. It is possible that data was corrupted on its way from the computer to
the plotter.
1. Try removing networks, spoolers, and/or switch boxes. Directly
connect the computer to the plotter to isolate the problem.
2. If using an IBM PC or compatible or a Sun workstation with an
RS232 port:
a. Try another serial cable. A bad serial cable can cause the
data to be dropped on its way from the computer to the
plotter. The plotter uses a straight-through, 25-pin
female to 25-pin male serial cable (CalComp part number
11772-0250, 25 foot serial cable) This is not a
proprietary cable. It is commercially available, sometimes
called a MODEM cable. A NULL-MODEM cable will not work.
b. The total cable length should not exceed 50 feet. For
testing purposes a shorter cable can decrease the error
factor.
c. If the computer has a 9-pin connector for the COM port
(i.e. COM1 or COM2), a commercially available 9 to 25 pin
adapter is acceptable to perform the conversion.
d. Connect the cable to the port on the back of the plotter
labeled: P0903 - To DTE Host.
3. If using a Macintosh computer:
a. Try a different communications cable. The plotter uses an 8-
pin mini-din Macintosh to 25-pin serial cable (CalComp part
number 16623-0029, 12 ft. cable).
4. Send a different plot file. The plot file being sent may be
corrupt.
5. Try plotting from another computer. The port on the computer may
be defective
6. If using AutoCAD:
a. If arrowheads are not plotting, set the Pen Optimization
Level to zero (or no optimization). The Pen Optimization
dialog box is located in the AutoCAD Plot Menu if using
versions 12 or 13 of AutoCAD. This usually resolves the
problem. Also, check to see that the pen widths are set to
0.010 in the AutoCAD Pen Assignment menu.