Download PLC and Analog Output Interfaces

Chapter 1: Allen-Bradley RIO Option Card
Data Definition
Data requirement: rotation of gross weight and rate updated on A/D
Step #
Scale command (from
Scale Floating
Command response from
Floating Point
terminal
Value
PLC)
Point Value
1
3 (dec) loaded into
(PLC clears out any previous
command word O:XX1
rotation with reset)
2
Command ack.= 1
(JAGXTREME terminal sees new
F.P. ind = 30
command)
3
40 (dec) loaded into
(null value)
(PLC adds gross weight to
command word O:XX1
rotation)
4
Command ack. = 2
(JAGXTREME terminal sees new
F.P. ind = 30
command)
5
46 (dec) loaded into
(PLC adds rate to the rotation)
command word O:XX1
6
Command ack. = 3
(null value)
(JAGXTREME terminal sees new
F.P. ind = 30
command)
At this point, the rotation has been set up. Now the PLC needs to command the JAGXTREME terminal to begin the rotation.
7
0 (dec) loaded into
(PLC sends the command to
command word O:XX1
begin the rotation at A/D)
8
Command ack. = 0
Floating point
(JAGXTREME terminal sends
F.P. ind = 0
value = gross wt.
gross weight at A/D update ~ 58
msec)
9
0 (dec) loaded into
Command ack. = 0
Floating point
(PLC leaves 0 in its command
F.P. ind = 6
value = rate
command word O:XX1
word and the JAGXTREME
terminal sends the rate value at
the next A/D)
10
0 (dec) loaded into
Command ack. = 0
Floating point
(PLC leaves 0 in its command
F.P. ind = 0
value = gross wt.
command word O:XX1
word and JAGXTREME terminal
sends the gross value at next
A/D)
11
0 (dec) loaded into
Command ack. = 0
Floating point
(PLC leaves 0 in command word
F.P. ind = 6
value = rate
command word O:XX1
and JAGXTREME terminal sends
the rate value at the next A/D)
This rotation continues until the PLC sends a different command. At approximately every 58 msec the JAGXTREME terminal updates
its data with the next field in its rotation. The PLC must check the floating point indication bits to determine which data is in the
floating point value.
(1/03)
1-15