4.4 Special functions list -- SF
4.4.26 Analog Multiplexer
Short description
This special function outputs one of four predefined analog values or 0 at the analog output.
Symbol in LOGO! Wiring Description
Input En A change in status from 0 to 1 at input En (Enable) switches a parameterized analog value to the output AQ, depending on the value of S1 and S2.
Inputs S1 and S2 S1 and S2 (selectors) for selecting the analog value to be issued.
• S1 = 0 and S2 = 0:
Value 1 is issued
• S1 = 0 and S2 = 1:
Value 2 is issued
• S1 = 1 and S2 = 0:
Value 3 is issued
• S1 = 1 and S2 = 1:
Value 4 is issued Parameter V1...V4: Analog values that
will be issued.
Range of values:
--32768...+32767 p: Number of decimals
Range of values:
0, 1, 2, 3
Output AQ This special function has an analog output. This output can only be connected with the analog input of a function, an analog flag or an analog output connector (AQ1, AQ2).
Range of values for AQ:
--32768...+32767 Parameters V1...V4
The analog values for the parameters V1...V4 can be derived from another already--programmed function. You can use the actual values of the following functions:
• Analog comparator (actual value Ax -- Ay, see Chapter 4.4.18)
• Analog threshold trigger (actual value Ax, see Chapter 4.4.16)
• Analog amplifier (actual value Ax, see Chapter 4.4.20)
• Analog multiplexer (actual value AQ)
LOGO! functions
Parameter p (number of decimals)
Applies only to the values displayed in a message text.
Timing diagram
If input En is set, then the function issues one of 4 possible analog values V1 to V4 at the output AQ, depending on the value of S1 and S2.
If the input En is not set, then the function issues the analog value 0 at output AQ.
Analog output
If you interconnect this special function with a real analog output, note that the analog output can only process values between 0 and 1000. To do this, you may need to connect an additional amplifier between the analog output of the special function and the real analog output. Using this amplifier, you standardize the output range of the special function to a value range of 0 to 1000.
Setting the Par parameter
View in programming mode (example):
B3 1+/
View in parameter assignment mode:
B3 1
4.4.27 Analog Ramp
Short description
The Analog Ramp instruction allows the output to be changed from the current level to the selected level at a specified rate.
Symbol in LOGO! Wiring Description
Input En A change in the status from 0 to 1 at input En (Enable) applies the start/stop level (Offset ”B”
+ StSp) to the output for 100 ms and starts the ramp operation to the selected level.
A change in the status from 1 to 0 immediately sets the current level to Offset ”B”, which makes output AQ equal to 0.
Input Sel SeI = 0: Level 1 is selected SeI = 1: Level 2 is selected
A change in status of Sel causes the current level to start changing to the selected level at the specified rate.
Input St A change in the status from 0 to 1 at input St (Decelerated Stop) causes the current level to decrease at a constant rate until the start/stop level (Offset ”B” + StSp) is reached. The start/stop level is maintained for 100ms and then the current level is set to Offset ”B”, which makes output AQ equal to 0.
LOGO! functions
Symbol in LOGO! Wiring Description
Parameter Level 1 and Level 2:
Levels to be reached
Range of values for each level:
--10,000 to +20,000 MaxL:
Maximum value that must not be exceeded under any circumstances.
Range of values:
--10,000 to +20,000 StSp:
Start/Stop offset:
value that is added to Offset ”B” to create the start/stop level. If the Start/Stop offset is 0, then the start/stop level is Offset ”B”..
Range of values:
0 to +20,000 Rate:
Acceleration with which level 1, level 2 or Offset is reached. Steps/seconds are issued.
p: Number of decimals Range of values:
0, 1, 2, 3
Output AQ The output AQ is scaled using the formula:
Range of values for AQ:
0 to +32767
(Current Level -- Offset ”B”)/ Gain ”A”
Range of values:
0 to +32767 Note:
When AQ is displayed in parameter mode or message mode, it is displayed as an unscaled value (engineering units: current level).
Parameters L1, L2
The analog values for the parameters L1 and L2 can be derived from another already--programmed function. You can use the actual values of the following functions:
• Analog comparator (actual value Ax -- Ay, see Chapter 4.4.18)
• Analog threshold trigger (actual value Ax, see Chapter 4.4.16)
• Analog amplifier (actual value Ax, see Chapter 4.4.20)
• Analog multiplexer (actual value AQ, see Chapter 4.4.26)
• Analog ramp (actual value AQ)
• Analog math (actual value AQ, see Chapter 4.4.30)
• PI controller (actual value AQ, see Chapter 4.4.28)
• Up/down counter (actual value Cnt, see Chapter 4.4.13)
Select the required function by the block number. For information on parameter defaults, refer to Chapter 4.4.1.
Parameter p (number of decimals)
Applies only to the AQ, L1, L2, MaxL, StSp and Rate values displayed in a message text.
Timing diagram for AQ
En
Sel
Level 2 Level 1
Rate Rate
Rate Rate
St
StSp+B
100 ms 100 ms 100 ms
MaxL
B AQ
LOGO! functions
Functional description
If the input En is set, then the function sets the current level to StSp + Offset ”B” for 100 ms.
Then, depending on the connection of Sel, the function runs from the level StSp + Offset ”B” to either level 1 or level 2 at the acceleration set in Rate.
If the input St is set, the function runs to a level of StSp + Offset ”B” at the
acceleration set in Rate. Then the function holds the level at StSp + Offset ”B” for 100 ms. After 100 ms, the level is set to Offset ”B”. The scaled value (output AQ) is 0.
If the input St is set, the function can only be restarted after the inputs St and En have been reset.
If input Sel has been changed, depending on the connection of Sel, the function runs from the current target level to the new target level at the rate that is specified.
If the input En is reset, the function immediately sets the current level to Offset ”B”.
The current level is updated every 100 ms. Note the relationship between output AQ and the current level:
Output AQ = (current level -- Offset ”B” / Gain ”A”)
Note
For further information on analog value processing please refer to the online help for LOGO!Soft Comfort.
Setting the Par parameter
View in programming mode (example):
B3 1+/
Decimals in the message text
B3 3+/
View in parameter assignment mode:
B3 1
L1 =+04000 L2 !B020 AQ =00250
B3 2
StSp=00222 Rate=00500
Press A "
Press A "
B3 3+/
A =02.50
B =-00300
OffsetGain
4.4.28 PI controller
Short description
Proportional-action and integral-action controllers. You can use both types of controller individually or combined.
Symbol in LOGO! Wiring Description
A/M R PV Par
AQ
Input A/M Set the mode of the controller:
1: automatic mode 0: manual mode
Input R Use the input R to reset the output AQ. As long as this input is set, the input A/M is disabled.
Output AQ is set to 0.
Input PV Analog value: process variable, influences the output