CH. 2
14 MAY 2002
PAGE 11
MAN0484-01
Table 2.3 - %Q Definitions for Transmit Channel
%Q Register
Description
Qx
Transmit Command
Qx+1
Type of Transmit (0 for send data)
Table 2.4 - %I Definitions for Transmit Channel
%I Register
Description
Ix
Transmit Complete
Ix+1
Transmit Error
Ix+2
Bus Off Error
Ix+3
Power Fail Error
2.4.2
Transmit Channel Operation Overview
The %AQs contain the information to be transmitted, the %Rs contain data from the device, the %Qs are
used to control when and what to transmit, and the %Is report the status. Toggling %Qx from 0 to 1
triggers the JCM200 to send the data. The value of %Qx+1 determines the type of transmit, where 0
equals send data and 1 equals low priority request. The %AQ usage changes depending on the value of
%Qx+1.
%Ix goes to 1 when the transmit operation completes, thus notifying the PLC that another transmit can
occur. %Ix+1 indicates whether or not a transmit error occurred, where 0 equals OK and 1 equals an
error.
Toggling %Qx from 1 to 0 clears the %Ix and %Ix+1 in order to setup for another transmit.
The following sections describe the how the %AQ and %AI registers are used.
2.4.3
Send Data
When the transmit channel is used to send data to a device on the network then the 11 %AQs, 2 %Qs
and 2 %Is are used.
Send Data Register Use:
The %AQs contain the information to be transmitted. The %AQs need to be loaded with the appropriate
data before %Qx is toggled from a 0 to 1 to initiate the transmit.
The following is a detailed description of the %AQ data:
%AQx contains the PGN where the associated data will be written
%AQx+1 contains the destination address of the device that the data is being sent to
%AQx+2 contains the number of bytes of data to be sent, up to 8 bytes.
%AQx+3 - %AQx+10 contains the data to be sent. Note that %AQs are word values but the data should
only be a byte value. The upper byte of the word should be 0. Received values are packed into word
values (low byte and high byte are separate returned values). The bytes for the transmit channel are
separated for ease of configuration and use.
