750-00004 Parallax Inc, 750-00004 Datasheet - Page 20

• Manufacturer Part Number: 750-00004
• Description: POWER SUPPLY 24VDC 600MA
• Manufacturer: Parallax Inc

Specifications of 750-00004

• Form: Wall Mount (2 Prong)
• Voltage - Output Per Connector: 24VDC
• Current - Output: 600mA
• Polarization: Positive Center
• Cord Plug: 2.1mm I.D. x 5.5mm O.D. x 12mm Female
• Voltage - Input: 120VAC
• Power - Output: 14W
• Transformer Type: Linear, Unregulated
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Efficiency: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Set_Password:
Clear_Password:
Remote Telemetry Unit
Data loggers are devices that record data to be retrieved at some later point in time. Another name for a
similar device is a Remote Telemetry Unit, or RTU. An RTU differs from a Data Logger in that it has a
limited amount of control ability. A good example of this type of RTU is a Dual Pump Controller. The
Dual Pump Controller is responsible for maintaining a parameter, like fluid level within a tank, by
controlling and monitoring two pumps.
Our Dual Pump Controller sample program is not as full-featured as it could be, but is complete enough
to get you pointed in the right direction. Since it is a comparatively long listing, we will break it into
sequential segments and discuss each block as it comes. There's not a lot to discuss with the first block,
but reading the program description and the note are good first steps.
' =========================================================================
'
'
'
''
'
'
Parallax, Inc. • Stamp PLC (#30064) • Version 1.8 • 12/29/2003
FOR keyIn = 0 TO 3
NEXT
keyIn = serString(0)
RETURN
DEBUG CR, "Enter a 4-character password", CR
SERIN 16, Baud, [STR serString\4]
DEBUG CR, "Confirm password: "
SERIN 16, Baud, [WAITSTR serString\4]
FOR keyIn = 0 TO 3
NEXT
DEBUG CR, "Password set", CR, "Working!", CR
keyIn = "N"
RETURN
FOR keyIn = 0 TO 3
NEXT
DEBUG CR, "Password cleared", CR
keyIn = "C"
RETURN
READ keyIn, serString(keyIn)
WRITE keyIn,serString(keyIn)
WRITE keyIn, $FF
serString(keyIn) = $30
File....... Stamp PLC_PumpController.BS2
Purpose.... Dual Pump Controller.
E-mail..... [e-mail]
Started.... 27 JUN 2003
Author..... Parallax, Inc.
Before the advent of small microcontrollers, a simple float switch would have performed this task.
The Dual Pump Controller can do this as well as several other useful features:
Rotate duty between two pumps – evening the wear.
Use only one pump if the other is out of commission.
Use both pumps if the level is very low.
Record periodic tank levels and other parameters at periodic intervals.
Record the amount of run-time of each pump.
Send a notification if there is a fault with a pump.
Transmit the data recorded when called for.
Example program.
' User interface to enter
' password
' Write password to eeprom
' Clear password in RAM
' to $FF's and in eeprom
' to "0"'s
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