PCL-2 Pulse-to-Current Loop Converter

PCL-2 Pulse-to-Current Loop Converter

The PCL-2 2nd generation Pulse-to-Current Loop Converter is a device designed to convert a 2-Wire KY pulse to an analog 4-20mA signal, readable by another device with a 4-20mA input. The 4-20mA current output of the PCL-2 can be configured to represent the current Instantaneous or Average rate-of-usage in electric, water, gas metering or non-energy related general-purpose applications. The KY pulse output from a meter or isolation relay is fed directly into the PCL-2’s KY input. The PCL-2’s input provides a +13VDC wetting voltage for the meter’s dry contacts.


Upon receiving each pulse from the meter, the PCL-2’s microcontroller calculates the rate of usage based on the pulse rate and value, and updates the current loop output to the calculated level between 4mA and 20mA. For example, suppose you have the full-scale output of the PCL-2 configured for 500kW. If a current demand of 250kW is calculated, the output would be adjusted to 12mA, the 50% midpoint between 4 and 20mA.

If the Average output mode is selected (Electric Mode only), the output for a selected demand interval --from 1 to 60 minutes – is calculated continuously and the 4-20mA output represents the current interval’s rolling average demand, or rate of usage. The average Demand is updated every 15 seconds.

Programming of the PCL-2 is quick and easy using the SSI Universal Programmer software through the PCL-2's USB port, or with a PC terminal program like TeraTerm, Puddy or ProComm.

The PCL-2 uses a 12-bit Digital-to-Analog Converter so resolution is 1/4096th of full scale. A bright red LED lamp indicates the input’s status at all times. An additional Green LED indicates when the output is written to.  Additional provisions are made to easily read the output’s current level with a precision digital multimeter.
Typical applications include interfaces between utility metering devices and customer-owned energy management control systems, SCADA systems, recorders or programmable logic controllers. A +24VDC loop power supply is all that is necessary to implement the 4-20mA current loop. The PCL-2 has built-in transient and reverse polarity protection on the 4-20mA current loop output that eliminates the need for external protection.

PCL-2 Pulse-to-Current Loop Converter Diagram

Power Input:120-277VAC. Burden: 10 MA. at 120 VAC
Input: One KY Form A (2-wire)input with +13VDC wetting voltage compatible with dry-contact, open-collector transistor or open-drain FET transistor output.
Output:One 4 – 20 mA current loop output. +5VDC maximum voltage output.
Operational Modes: General Purpose, Electric, Water, Gas
Output Impedance: 600 ohms maximum, 250 ohms typical
Loop to Control Isolation Voltage:5000Vrms
Output Update Time: Fixed at second
Maximum Input Pulse Rate: 100 pulses per second
Pulse value: 1 to 99999 in 1 unit increments.
Full scale selection:1 to 99999 units
Demand Averaging interval selection: 0-60 minutes.

Mounting: Any position
Size:3.50 inches wide, 7.20 inches high, 1.50 inches deep
Weight:17 ounces

Temperature Range:

-38º C to +70º C, -38.4º F to +158º F

Humidity: 0 to 98% non-condensing

Available Options
Input Voltages:12VDC

All specifications are subject to change without notice.