MX8000 Installation and Operation Guide
8–32
8.9.4 Test
Record
A test record is sent when panel date/time is updated.
The following is an example of a test record:
<$0A><"IT IRCV 234A"><$0D>
Table 8–36: Test Record Components and Description
Character Description
<$0A>
Start of record (line feed).
<"IT IRCV 234A">
Predefined test record string. The predefined test string is automatically set
when ITI Generic format is chosen to communicate with automation computer.
<$0D>
End of record indicator (carriage return).
8.9.5 OKAY
Record
When the automation computer sends a supervisory character to the MX8000 receiver, the receiver will
return with an OKAY record. An OKAY record (heartbeat) is sent periodically to the automation computer.
How often the OKAY record is sent is set through programming (see Section 5.4.3.5 page 5–18).
Note:
The supervisory character is programmable. See Section 5.4.3.5 page 5–20.
The following is an example of an Okay record:
<$0A><"00 OKAY @"><$0D>
Table 8–37: Okay Record Components and Description
Character Description
<$0A>
Start of record (line feed).
<"00 OKAY @">
Predefined okay record string. The predefined okay record string is
automatically set when ITI Generic format is chosen to communicate with
automation computer.
<$0D>
End of record indicator (carriage return).
8.9.6 ACKing and NACKing Data
After the end of message byte (
<0Dh>
) is sent by the receiver, the automation computer will respond with an
ACK (
<$06>
) or NACK (
<$15>
). This response can be delayed between 1 byte time (depending on the baud
rate) and the ACK timeout period. See Section 5.4.3.5 page 5–19.
If the receiver doesn’t get an ACK within the ACK timeout period or receive a NACK from the automation
computer, it will re-transmit the data.
After two NACKs or two ACK timeouts the receiver will generate a
Computer Trouble
message. When a
computer trouble message is generated, the receiver will continually send a heartbeat until it receives an
ACK from the automation computer. When communication is restored, a Computer Trouble Restore message
will be generated.
8.10 ITI Computer Interface Format
ITI Computer Interface format consists of four types of records; report record, test record supervisory record,
and log record (see Table 8–39).
8.10.1 Convention Used In This Section
An ITI digit in this section is an ASCII representation of a number from 0 to 61 as follows: