Archive for DC Voltage and Current

DC Isolators

Wici LogoDC Isolators

Provide galvanically isolated DC Output proportional to DC Input

Wilkerson Instrument Co.     800-234-1343 Wilkerson Instrument Co Blog Page   Wilkerson Instrument Co LinkedIn Page

Isolators are used to break ground loops and to measure signals with high common mode voltages.

Ground loops are created when the source of a signal and the driven instrument have their common inputs tied to the earth at each device or the common lead is used to carry AC current for some other device.  AC current flowing in the common lead drops a small AC voltage due to the wire resistance. The voltage appears in series with the desired signal and creates “noise” on the desired signal.  The Isolator breaks the common lead and the AC current can no longer flow.

A common mode voltage is a voltage that is connected to the + and – inputs of a device.  Example – A small resistor in series with the + lead of a 138VDC battery and the – side of the battery is the “common” lead for the system.  The resistor drops a small voltage proportional to the battery current.  The Isolator can measure the small voltage across the resistor even though it is floating 138VDC above the system circuit common.

MM4380A Field Rangeable DC-DC Isolator Picture

Mighty Module Series Logo Series

MM4380A Field Rangeable Input and Output
Span ± 16mV to ± 256VDC, ± 0.8mA to ± 100mA
Offset Cancel ±110% of Span
MM4300 Factory Ranged Input and Output
Span ± 50mV to ± 250VDC, ± 1mA to ± 1ADC
MM4300A Four Models, Combinations of 4/20mA and 0/10VDC Input and Output
Mighty Module DC-DC Isolator Picture

UL/cUL Recognized
MM4380A and MM4300

DinMod Series Field Rangeable DC-DC Isolator Picture

DIN-MOD Series Logo Series

DM4380A Field Rangeable Input and Output
Span ± 16mV to ± 256VDC, ± 0.8mA to ± 100mA
Offset Cancel ± 110% of Span
DM4300A Four Models, Combinations of 4/20mA and 0/10VDC Input and Output
DM4391 Loop Powered Isolator
4/20 mADC In and Out
Linearized ± 0.02% of Span

UL/cUL Recognized
DM4380A and DM4300A

DR Series DC-DC Isolator Picture DR Series Logo

DR4380A Field Rangeable Input and Output
Span ± 50mV to ± 256VDC, ± 1mA to ± 100mA
DR4300 Factory Ranged Input and Output
Span ± 50mV to ± 250VDC, ± 1mA to ± 250mADC
DR4302

Inputs: 1/5, 0/10VDC; 0/1, 4/20, 0/20, 0/50mADC
Outputs: Dual Isolated 4/20mADC

 

UL/cUL Recognized

Silver Series DC Isolated Two-Wire Transmitter Picture

50 mm Diameter

Silver Series Logo

SR2101 Isolated 2 Wire Transmitter, Head or DIN Rail Mount
Factory Ranged Input ± 16mV to ± 128 VDC, ± 0.01mA to ± 100mADC
30th Anniversary Banner

Wilkerson Instrument celebrates 32 years experience designing, manufacturing, distributing, and providing engineering help for the process control industries.

Phone always answered by a live person

Other Products:

  • Wireless Data Acquisition and Control
  • Loop Powered Displays
  • DC Motor Drives
  • DC Isolation
  • Frequency Inputs
  • Turbine Flow Meters

 

Industries Served:

  • Water and Waste Water
  • Power Generation
  • Bottling and Food Processing
  • Transportation
  • Chemical Processing
  • (OEM) Original Equipment Manufacturer

Wilkerson Instrument Company Inc.
2915 Parkway Street
Lakeland, FL. 33811 U.S.A
Wici.com

Wilkerson Instrument Co Blog Page   Wilkerson Instrument Co LinkedIn Page

800-234-1343    863-647-2000

Prevent Overflow – Duplex Lift Station Back-Up Pump Controler

The DR1920 Back-Up Pump Control is a compact DIN rail mounted unit used to monitor
a backup High-High Level Alarm in a tank or wet well and to start up to two pumps when the High-High Alarm switch closes.dr-seriessm

It prevent overflows in situations where the primary level control system fails.

When the High-High Alarm switch in the tank or well closes, the DR1920 closes a relay that starts Pump 1 and starts an internal Timer 1. When Timer 1 reaches its set time, and the High-High Alarm switch is still closed, Pump 2 is started.

Pump 1 and Pump 2 will run until the High-High Alarm switch opens. When the
High-High Alarm switch contact opens, Timer 2 is started and both pumps continue to run until Timer 2 reaches its set time.

If the High-High Alarm switch opens during the Timer 1 interval, Timer 2 is started when the High-High Alarm switch opens. Pump 2 is not started and Pump 1 will run until Timer 2 reaches its set time. Timer 2 is set by the user to lower the level ito the desired low level.

The DR1920 also has provisions to alarm on a switch opening.

ALARM SWITCH MONITOR

The DR1920 monitors the open or closed status of a switch contact that is already
wired into a control system. This switch may have any of several voltages that are
used to control the pump system. In addition, if the primary control system fails, the normal voltages may not be present.

The DR1920 is wired across the alarm switch contacts and uses a unique circuit
that measures the impedance present between the switch contacts.

When the DR1920 senses a low impedance, it begins its control function, regardless of any absence or presence of voltage across the switch contacts. This feature allows the
DR1920 to be wired in parallel across the switch contacts without regard to the
existing control system, permitting simple installation in existing systems.

For situations where the existing wiring prevents this circuit from being used, an
isolated contact must be provided. A second input, which requires an isolated contact or
open collector transistor (optical isolator) is also provided.

A Reset input is provided to stop the pumps and reset the timers. It requires a contact
closure or open collector transistor which will conduct. Since the Back Up Pump Control is used
only when there is a problem with the primary control, the digital alarm inputs, as
well as the reset inputs, are provided to allow the periodic exercising of the system
to verify functionality.

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