• Microprocessor Based

• “Auto-Set” (Pushbutton Calibration

• Modular Construction

• Multi-Point Control (1-4) Relays, Using Only One Sensor (Probe)

• Economical, Cost Much Less Than 4 Individual Controls

• Up To 1 Mile Signal Transmission Between Probe/PFM & Control Unit Using 2 Plain Wires

• Independent Time Delay and Adjustable Differential For EACH Relay

• Lead/Lag Feature For Automatic Pump Alternation

• Heavy Duty 10 Amp Relays

• Self-Diagnostics With LED Failure Indication

• Designed For Maximum EMI and RFI Rejection

• Optical Isolation Between PFM and Controller

• Non-Volatile Calibration Memory

• Optional Indicating Lights

• Optional AC or DC Supply Power

• Optional Enclosures (NEMA 4, 4X or Explosion- Proof

• UL and c-UL Listed

GENERAL DESCRIPTION

The ROBERTSHAW Level-Lance Model 5400A is a microprocessor based, multi-point On-Off capacitance type level detection system. Utilizing the Pulse Frequency Modulation (PFM) method of signal transmission ensures that accuracy, repeatability and longevity are enhanced over level systems using conventional analog transmission schemes. The PFM transmitter, normally mounted directly on the sensing probe, requires no calibration or adjustments of any kind. The control unit can be mounted up to one mile from the PFM transmitter without requiring any special type of interconnecting wire or cable. Two wires are all that is required. The PFM transmitter does not require any primary power because it receives its operating power from the control unit over the same two wires used to transmit the level signal.

The PFM transmitter is also designed to provide electrostatic protection at the probe input. It transmits a frequency modulated pulse signal to the microprocessor based control unit. The variation in the frequency of the pulse is proportional to the product level on the sensing probe. The microprocessor in the control unit receives the pulse and processes it to extract the level information. The microprocessor then compares this level information to the “AUTO-SET” calibration data stored in the non-volatile memory. When the level data coincides with this previously stored data, the appropriate output relay is either activated or deactivated, to give the desired control action. The total system design has been optimized to yield the highest possible levels of both EMI and RFI rejection.

The Model 5400A Level-Lance is calibrated by means of the “AUTO-SET” feature. This feature permits all calibration of the unit to be done by the simple act of pushing a button.