Exp - Exponential Function
This is a mathematical function that return the exponential (e^expression) of a floating-point value.
Arguments
IN
A floating point value.
Return Values
Q
e raised to the power of IN.
Example
Target/ Language Restrictions
None.
See Also
LN
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Filter - First-order Digital Filter
This is a signal processing function that returns the output of a first-order filter function with input expression as the input. The time-constant of the filter depends on the time-constant specified, and how often the FILTER statement is executed. The function can be used to filter integer and floating-point values.
Note that the FILTER block cannot be used in the INITIAL, BACKGROUND, ERROR or EVENT tasks.
Arguments
IN%/ IN
The integer or floating-point value to be filtered.
time%
The number of calls over which the filter is to be applied. If time% is set to 0, the option module will trip with a Maths error (trip 50).
Return Values
Q/ Q%
The filtered input value.
Example
The following code shows how a filter can be applied to a parameter value.
If a step change of 0 to 1000 is applied to #18.12, the output of the filter will be as shown in the following diagram.
Target/ Language Restrictions
None.
See Also
AVERAGE
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Float - Integer to Floating Point Conversion
This function converts an integer value to a floating-point value.
Arguments
IN%
The integer value to be converted.
Return Values
Q
The floating-point version of IN%.
Target/ Language Restrictions
None.
See Also
FLOAT32
INT
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Float32
This function converts a floating-point value to the IEEE single-precision format and forces the value into a DPL 32-bit signed integer. The integer can then be transferred over CTNet or fieldbus. Accuracy of the value is mainted to 7 digits.
This allows real decimal values to be transferred over CTNet without any need to convert to fixed point accuracy, which needs to be known at each end of a cyclic link. Some PLCs also use the IEEE Single Precision format to send real numbers, so Float32 will allow such a number to be decoded when received, or encoded for transmission to the PLC.
NOTE: This block converts both an IEEE Single Precision number AND a real decimal number on the same pass. If only one conversion is required, the un-used input should be set to 0. The corresponding output will be set to 0 when Float32 has completed.
Arguments
RealI
The floating-point value that is to be converted into IEEE single-precision and returned in output IntO%
IntI%
An integer containing an IEEE single-precision value that is to be converted in a DPL floating-point value in output RealO.
Return Values
RealO
The floating-point version of the IEEE single-precision value embedded in the input IntI%.
IntO%
The IEEE single-precision value (embedded into an integer) of the floating-point input RealI.
Target/ Language Restrictions
None.
See Also
FLOAT
INT
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GETCAN
This function retrieves a received CAN frame from a slot in the SM-CAN or UD77-CAN option. It should be used after a call to CANStatus or CANStatusAll indicates that a message has been received in a slot.
Arguments
Slot%
Specifies the CAN slot from which the received frame is to be returned. For Unidrive SP, the parameter is also used to indicate that option slot containing the SM-CAN option from which the frame is to be obtained.
For UD77, the argument can take the following values.
Return Values
Q%
The CAN slot status.
|
Value |
Meaning |
|
0 |
CAN slot read failed. |
|
1 |
CAN slot read successful. |
Len% - 0 to 8
The number of data bytes in the received message.
Word0%
The 32-bit word containing bytes 0 (LSB) to 3 (MSB) of the CAN data field. Unused bytes will be cleared to zero.
Word1%
The 32-bit word containing bytes 4 (LSB) to 7 (MSB) of the CAN data field. Unused bytes will be cleared to zero.
Time%
A timestamp which can be used to determine the order in which slots received frames. It does not provide accurate timing. On UD77-CAN, only slots 0 through 7 return the timestamp; slots 8 to 15 return -1.
Target / Language Restrictions
Only available on SM-Applications, SM-Applications Lite and UD77-CAN.
See Also
CANConfigEvent
CANGetNodeAddr
CANReady
CANSetup
CANStatus
CANStatusAll
EnableCANTrips
PUTCAN
ResetCANTimer
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