Rockwell Automation PLC-5 Fieldbus Solutions for Integrated Architecture User Manual - Manual (Page 24)

Publication 1757-UM006A-EN-P - May 2002
1-10 The Fieldbus Communication Model
Table 1.D Analog Input Block Specifications
Description The AI function block takes the input data from a Transducer block and calculates an output to be fed to other fieldbus
function blocks. A functional schematic of the block is shown in Figure 1.4 for reference.
Function Notes • Supports Out of Service (OOS), Manual (Man), and Automatic (Auto) modes.
• The XD_SCALE units code must match the channel units code, or the block will remain in OOS mode after being
configured.
• The OUT_SCALE is normally the same as the transducer, unless the L_TYPE is set to Indirect or Ind Sqr Root, then
the OUT_SCALE determines the conversion from FIELD_VAL to the output.
• If the mode is Auto, the PV is the value the block puts in OUT.
• If the mode is Man, an operator can write a value to OUT.
• The SIMULATE parameter is for testing purposes only and always initializes in the disabled state.
Equation Options FIELD_VAL = 100 x (channel value - EU@0%) / (EU@100% - EU@0%) [XD_SCALE]
Direct: PV = channel value
Indirect : PV = (FIELD_VAL / 100) x (EU@100% - EU@0%) + EU@0% [OUT_SCALE]
Ind Sqr Root: PV = sqrt(FIELD_VAL / 100) x (EU@100% - EU@0%) + EU@0% [OUT_SCALE]
Parameters
(see Appendix A
for definitions of
each parameter) ACK_OPTION
ALARM_HYS
ALARM_SUM
ALERT_KEY
BLOCK_ALM
BLOCK_ERR
CHANNEL
FIELD_VAL
GRANT_DENY HI_ALM
HI_HI_ALM
HI_HI_LIM
HI_HI_PRI
HI_LIM
HI_PRI
IO_OPTS
L_TYPE
LO_ALM LO_LIM
LO_LO_ALM
LO_LO_LIM
LO_LO_PRI
LO_PRI
LOW_CUT
MODE_BLK
OUT
OUT_SCALE PV
PV_FTIME
SIMULATE
ST_REV
STATUS_OPTS
STRATEGY
TAG_DESC
UPDATE_EVT
XD_SCALE