LADDER LOGIC FOR WEIGH SCALE / WEIGH FEEDER TOTALIZER.
LET THERE IS A WEIGH SCALE. THE WEIGH SCALE CONTROLLER GIVES A TOTALIZER PULSE DI FOR EACH 50 KG MATERIAL PASSED.
LET HERE, FOR EASE OF UNDERSTANDING, THAT WORK IS DONE BY A TIMER.
FOR EVERY 5 SECONDS 50KG MATERIAL PASSED THROUGH THE WEIGH SCALE.
SO, AT EVERY 5 SECONDS TIMER DONE BIT WILL BE HIGH.
NOW THE COUNTER WILL COUNT EACH TIMER DONE BIT.
MAXIMUM VALUE OF TOTALIZER IS 1000 TONS.
FOR 50 KG OF MATERIAL, WE GET 1 TOTALIZER PULSE.
FOR 1000 TONS OF MATERIAL, WE WILL GET 20000 TOTALIZER PULSES.
SCALE WITH PARAMETER
THE INPUT VALUE IS SCALED TO A RANGE DETERMINED BY CREATING A LINEAR RELATIONSHIP BETWEEN INPUT MIN AND MAX VALUES AND SCALED MIN AND MAX VALUES. THE SCALED RESULT IS RETURNED TO THE ADDRESS INDICATED BY THE OUTPUT PARAMETER.
THE INPUT MINIMUM, INPUT MAXIMUM, SCALED MINIMUM, AND SCALED MAXIMUM ARE USED TO DETERMINE THE SLOPE AND OFFSET VALUES. THE INPUT VALUE CAN GO OUTSIDE OF THE SPECIFIED INPUT LIMITS AND NO ORDERING IS REQUIRED. FOR EXAMPLE, THE SCALED OUTPUT VALUE WILL NOT NECESSARILY BE CLAMPED BETWEEN THE SCALED MINIMUM AND SCALED MAXIMUM VALUES.
PRESET VALUE IS THE POINT WHICH MUST BE REACHED TO SET THE DN (DONE) BIT.
THE ACCUMULATED VALUE REPRESENTS THE CURRENT STATUS VALUES.
A RES ALWAYS CLEARS THE STATUS BITS AND THE ACCUMULATED VALUE
Entering Parameters:
Input - Enter a value to be scaled. This can be a word address or an address of floating-point data elements.
Input Min - Enter a minimum value for the input (low end of range). This value can be a word address, a long (double-word) address, an integer constant, floating-point data element, or a floating-point constant.
Input Max - Enter a maximum value for the input (high end of range). This value can be a word address, a long (double-word) address, an integer constant, floating-point data element, or a floating-point constant.
Scaled Min - Enter a minimum scaling value representing the low end of the range to which you want to scale the input. The scaling relationship is linear. The value can be a word address, a long (double-word) address, an integer constant, floating-point data element, or a floating-point constant.
Scaled Max - Enter a maximum scaling value representing the high end of the range to which you want to scale the input. The scaling relationship is linear. The value can be a word address, a long (double-word) address, an integer constant, floating-point data element, or a floating-point constant.
Output - Enter an address for the scaled value that is returned after the instruction is executed. This value can be a word address, a long (double-word) address or an address of floating-point data elements. If any floating-point file types or floating-point constants are encountered in the above parameters, then the entire instruction is treated as floating-point, and all immediate integer data values are converted to immediate floating-point data values.
Note: The input minimum, input maximum, scaled minimum, and scaled maximum are used to determine the slope and offset values. The input value can go outside of the specified input limits and no ordering is required. For example, the scaled output value will not necessarily be clamped between the scaled minimum and scaled maximum values.
Addressing Help:
Enter a TIMER address, TIME BASE, PRESET value, and ACCUM (accumulated) value. Timer files use three words per element, one for instruction bits (the control word), one for the preset, and one for the accumulator.
T4:1 represents timer file number 4, element number 1.
Entering Parameters:
Enter a COUNTER address, PRESET value and ACCUM value. The preset value is the point which must be reached to set the DN (done) bit. The accumulated value represents the current count status.
C5:1 represents counter file number 5, element number 1.
This output instruction counts up for each false-to-true transition of conditions preceding it in the rung and produces an output when the accumulated value reaches the preset value. Rung transitions might be triggered by a limit switch or by parts traveling past a detector.
Note: Use a RES (reset) instruction with the same address as the counter, or another instruction in your program to overwrite the value. The on or off status of counter done, overflow, and underflow bits is retentive. The accumulated value and control bits are reset when a RES is enabled