TransCore MPRX, System Manual

Page: 85 / 208

MPRX
TransCore Proprietary 6–15
}
crctab[ch] = workval;
}
for (ch = 0; ch != MAX_CHAR; ch++)
printf(“0x%04x\n”, crctab[ch]);
}
Manually Disabling ECP for Maintenance
Under certain conditions, communications between the host and MPRX may be lost
temporarily and maintenance may be required. The reader or host is sending out a
message and waiting for an acknowledgment. When the acknowledgment is not received,
the message is sent again. Additional messages are also buffered. Often the first indication
that the MPRX software is in an ECP “loop” is when the user/technician sees a recurring
display of the same message repeated on the monitor. The procedure described in the
following paragraphs enables the maintenance technician to change configuration or test
tag reading manually.
Assuming that the ECP timeout is at the factory default of 12.7 seconds (or other value that
allows enough time for the commands to be manually entered) the following command
sequence may be used to break out of an ECP loop. This command sequence uses four
ASCII < ` > characters (60 hex) as wild card CRC values.
Note: The ASCII <`> character (60 hex) is commonly located on the ~ key.
You must acknowledge existing messages by issuing commands with the generic format:
#x@‘‘‘‘<eom>
where
#
Start-of-message character
x
Message sequence number. This must be the same as the sequence
number of the message being acknowledged
@
A
CK
(acknowledgment character)
<‘‘‘‘>
Wild card CRC value for the message
<eom>
End-of-message character
The following is a typical sequence after power-on limiting buffered messages.
Note: Ensure that no tags are in the field when you are performing this troubleshooting
procedure.
Caution
To avoid damage to the MPRX, ensure that you have connected the antenna or a
dummy load to the reader before applying power to the reader.