Plotter displays: HOST CHECK SUM ERROR message.
Plotter displays: HOST CHECK SUM ERROR message.
A. Checksum is a method of checking the integrity a block of data by
applying an algorithm to each byte in the block of data. The resulting
checksum character is appended as the last byte in the block. When
data is sent from the host, the checksum character sent from the host
is compared with a checksum character generated by the plotter. If the
checksum characters match, it is assumed that the transmitted data is
the same as the received data. If the characters don't match, it is
assumed the data is bad.
B. What can be done to eliminate the checksum error:
1. Check to see if the CAD software package is using checksumming.
Once you have verified what the software is using, check the
plotter's Set-up Menu and enable or disable the checksum feature,
as required. To locate the checksum menu on the plotter:
a. Turn the plotter power on.
b. Load and size the media by pressing the softkey under
MANUAL. The softkeys are the four light colored keys that
surround your plotter's display (Liquid Crystal Display).
c. After the plotter is done sizing the media, press the NEXT
key twice.
d. Select Set-up by pressing the softkey above SET-UP.
e. Select Host by pressing the softkey under HOST.
f. Press the NEXT key once.
g. Press the softkey under CHKSUM.
h. The plotter will display: PCI mode chksum (enabled) or
PCI mode chksum (disabled).
i. Choose enabled if the software is using checksumming.
Otherwise, choose disabled. Press either of the softkeys
below CHKSUM to make the selection.
j. Press the EXIT key three times. The plotter will prompt
you to save this change. Press the softkey for YES.
k. If you do not know if the software application is using
checksumming or not, and the Software User's Guide does
not provide this information, then you have a 50/50 chance
of oicking the correct answer. Try choosing enabled, and
if that still results in a checksum error, try disabled. The
important idea is that both the plotter and the software
match.
B. Factors other than the software and the plotter not matching can cause
a checksum error. If data is being dropped or added to on its way from
the host computer to the plotter, this can cause a checksum error
(i.e., the exact number of bytes that left the computer, did not arrive
at the plotter). To help isolate this kind of communication problem:
1. Eliminate any spoolers, buffers, networks, switch boxes, etc.,
and direct connect the plotter to the host computer.
2. If your are using an IBM PC or compatible or a SUN workstation
with an RS232 port:
a. Replace the serial cable that connects your PC to the
plotter. CalComp Serial Cable part number is: 11772-0250
and can be ordered by dialing 1-800-225-2667 and placing a
parts order. This is not a proprietary cable. You may
purchase a commercially available straight-through, 25 pin
female to 25 pin male, serial cable. This cable is also
known as a MODEM cable. You do not want NULL MODEM cable
that crosses pins 2 and 3.
b. If your PC has a 9 pin connector you can buy a commercially
available 9 to 25 pin adapter and plug the above straight-
through cable into that adapter.
3. If you are using a Macintosh:
a. Call 1-800-225-2667 and order the Macintosh serial cable
part number 16623-0029.
4. Send a different plot file. Your plot file may be corrupt.
5. Switch to a different host computer. There may be a loose
connection on the I/O card or an interrupt conflict.