Automationdirect.com Stellar SR44, User Manual

Page: 186 / 238

Chapter 6: Serial Communications
6.7.3 – Productivity3000 PLC Example Program (continued)
Enable
The following rungs are optional, and are included as an example of how to Read and Write to a parameter of the SoftStart. The SoftStart is 8-bit based,
so Reads actually return 2 values which have to be separated (shown on the next rung with theShift/Rotate instructions) so we can use them.
WriteReadTime
9
MODBUS READ
CPU-485
Slave Node Number 1
Automatic Polling 300 0
Don’t Skip Execution
Word Swap
No Mapping
Slave Modbus Starting Address 12
Modbus Decimal Addressing
Modbus Function Code 3: Read Holding Registers
Tag Name Mapping
Non-Array
Tag
P11-12Ped/Time
In Progress ReadStarterInProg
Complete ReadStarterCmplt
Success ReadStarterSuccess
Error ReadStarterErr
Timeout ReadStarterO
Exception
Response String ReadStarterException
This rung takes the value in tag “P11-12”, which was retrieved from the SoftStart, and performs some Shift operations on it to isolate the 2 values
that actually are retrieved from the SoftStart due to its 8-bit architecture. First, the value is Shifted Left by 8 bits (to zero out the data), and the result
is placed in tag “Shift1”. Next, tag “Shift1” is Shifted Right by 8 bits to return the value to its original location. The resulting value is stored in tag
“SoftStartTimeResult”. Finally, “P11-12” is Shifted Right to move the upper byte to the lower byte and the value is stored in tag “SoftStartPedestalResult”.
This is the value that is used to demonstrate how to Write/Read with the unit, since the “Soft Start Time” would be the most commonly changed
parameter, after Start/Stop.
Enable
10
10.1
Enable
10.2
Enable
This rung will write to the unit, updating P12 (”SoftStartTime”) with the latest entry (coming from an HMI, for example).
WriteReadTime
11
Enable
MODBUS WRITE
In Progress WriteStarterInProg
Complete WriteStarterComp
Success WriteStarterSuccess
Error WriteStarterError
Timeout WriteStarterTO
Exception
Response String WriteStarterException
Serial Port CPU-485
Slave Node Number 1
Automatic Polling 300 50
Don't Skip Execution
No Word Swap
Map 32 bit data to 16 bit
Slave Modbus Starting Address 13
Modbus Decimal Addressing
Modbus Function Code 6: Write Single Register
Tag Name Mapping
Non-Array
Tag
SoftStartTime
Input P11-12Ped/Time
Number of Bits 8
Shift Left
Bit to Shift In 0
Don’t Include Sign Bit
Output Shift1
SHIFT/ROTATE BITS
Input P11-12Ped/Time
Number of Bits 8
Shift Right
Bit to Shift In 0
Don’t Include Sign Bit
Output SoftStartPedestalResult
SHIFT/ROTATE BITS
Input Shift1
Number of Bits 8
Shift Right
Bit to Shift In 0
Don’t Include Sign Bit
Output SoftStartTimeResult
SHIFT/ROTATE BITS
SR44 Series Soft Starter User Manual
1st Ed, Rev B 07/31/2019
6–32