SMAR CD600 Plus - Function 30 - Output Selector (Osel); Operation

Library of Function Blocks
4.71
Function 30 - Output Selector (OSEL)
Operation
This block directs the input signal to one of the two outputs through switch CH1. When CH1 is
activated (high level at input
B), it directs the input to output 148 or 150.
BLK 107/108
A
B
148/150
147/149
0
1
CH1
When there is an output switching, the output not selected can hold the last signal value, or it can be
forced to go to 0 or 100%, as determined by parameter
CLST.
It is possible to lock the switch at position "0" with parameter CLCK.
EXAMPLE:
In pH control it is after useful to freeze the input while calibrating the pH - transmitter which is a
rather frequent procedure.
For this case the OSEL block can be used as a Sample-and-hold switch.
p
H
-
T
ransm
i
ter
OSEL
147/149
A
B
B
APIB
MND=HLD
CTYP=1
FV
D
AI
ADJ
Fig 4.30.1 - L/R Selector Configuration for setpoint tracking
The ADJ block is here used to turn the hold ON or OFF, when it is OFF (OSEL block input B is low)
the signal passes straight through the OSEL block, but when the OSEL block input B is high the hold
function is ON and the last value remains the input to the APID block. Hence the pH - transmitter
may be calibrated without disturbances.
TYPE MNEM DESCRIPTION RANGE DEFAULT
I LIA Input A 0
I LIB Input B - Selects the output
Addresses
0 to 170/225 to 240
0
I CLST Condition of output when not connected to the input
0 - Holds last value
1 - 0% / 2 - 100%
0
I CLCK Locks switch CH1 in position 0 0 - No/1 - Yes 0
Number of Bytes per Type of Parameter: A = 0 C = 4 L = 4