SOLID STATE INSTRUMENTS PCL-2 Pulse-to-Current Loop Converter Instruction Manual
- June 9, 2024
- Solid State Instruments
Table of Contents
INSTALLATION INSTRUCTION SHEET
PCL-2 Pulse-to-Current Loop Converter
PCL-2 Pulse-to-Current Loop Converter
MOUNTING POSITION – The PCL-2 can be mounted in any position. Two
mounting holes are provided.
POWER INPUT – The PCL-2 is powered by an AC voltage of between 120 and
277 volts. Connect the AC line’s “hot” wire to the L1 Line terminal. Connect
the AC line’s “neutral” wire to the NEU terminal. Connect the GND terminal to
electrical system Ground. Ground must be connected to electrical system
ground. If a true neutral does not exist, connect both the NEU and GND
terminals to ground. Warning: The PCL-2 Power input must be wired Phase-
toNeutral, NOT Phase-to-Phase. See wiring diagram on Page 6.
METER INPUT – The PCL-2 has a 2-Wire (Form A) pulse input. Connect the
PCL-2’s “Kin” and “Yin” input terminals to the meter’s “K” (-) and “Y” (+)
output terminals. The PCL-2’s “Kin” terminal is the common return. The +13VDC
wetting voltage is “pulled-up” internally on the PCL-2’s Yin terminal. Each
closure of the meter’s output line will “pull down” the Y input line to Z, the
common return, thus representing a pulse. A RED LED D6(next to the Yin input
terminal) shows when a pulse is received. All settings are programmed into the
PCL-2 by means of the USB Programming Port, and are saved in Non-Volatile
EEPROM memory, so they are never lost or inadvertantly changed. See page 8 for
“Programming the PCL-2”.
OUTPUT – The PCL-2 outputs a current of 4 to 20mA proportional to the
rate-of-usage calculated by the pulse value and full scale system settings
using 12-bit digital to analog conversion. For electric this is kW; for water
or gas, it’s gallons or CCF,respectively, per the selected unit of time. In
general purpose mode, the output is simply the number of pulses per unit of
time. Two output modes are available: Instantaneous or Average rate of usage
may be selected for output. Transient voltage protection for the output is
provided internally. The 4-20mA loop must be powered by a regulated +24VDC
Loop Power Supply, which is external to the PCL-2. This power supply supplies
all power to the output stage of the PCL-2 and is optically isolated from the
rest of the PCL-2.
OPERATION – See the following pages for a full explanation of the
operation of the PCL-2.
PCL-2 OPERATION
General Purpose Mode: The PCL-2’s General Purpose mode converts the number of
pulses per second, minute or hour to a 4-20mA Current with a fixed 1-second
update interval. This is the simpliest mode and only requires a programmable
maximum # of pulses per second, minute or hour over which the output current
is calculated. The pulse value is fixed at 1. Below is an example of how the
PCL-2 works in a General Purpose application and how it is programmed.
Example: Suppose you have
a variable speed motor application where you need to know the revolutions per
second. There is one pulse per revolution. The motor is 3450 RPM. Rounding up
to 3600 RPM gives us 60 pulses per second. The Full Scale pps value is set to
60. Therefore, 3600 RPM or 60 RPS = 20mA. Zero RPS = 4mA. Since the motor’s
revolutions per second is equal to pulses per second, the # of pulses/sec is a
direct relationship of revolutions per second. Assume that pulses being
received at this moment in time are at a rate of 43 pulses per second and the
load is steady. The conversion would be: 43/60 = 71.6% X 16mA = 11.4666mA +
4mA = 15.4666mA out. Output resolution is 16mA / 4096 steps or .003906 mA per
step. So, 4096 71.466% = 2927.247 steps of 4096. Rounding off to 2927 X
.003906mA = 11.433mA + 4mA = 15.4328mA output, which represents 43pps.
Accuracy = 99.78%.
Electric Mode: The PCL-2 Pulse to 4-20mA Current Loop Converter Module is
designed to output a current of between 4-20mA, which creates a voltage on the
loop proportional to the value of the instantaneous or average KW demand.
Below is an example of how the PCL-2 works in an electric application and how
it is programmed.
Example: Suppose a building has a 483KW maximum demand. Set the Full Scale
Value at 500 kW. Therefore, 500kW = 20mA. 0kW = 4mA. Resolution would be 500 /
4096 or .122 kW (or .0244% of full scale) per step. Assume the electric
meter’s PKe Pulse Form C (3-Wire) value is 240 wh/pulse (or .240kwh/pulse).
The 2-Wire equivalent is .480kWh/p or 480wh/p. Assume that pulses being
received at this moment in time are at a rate of one pulse per 4 seconds and
the load is steady. The conversion would be: .480 Kwh X 3600 = 1728 kW-sec / 4
sec = 432 kW. Output current is calculated as 432/500 = 86.4% X 16mA =
13.824mA + 4mA = 17.824mA out. Output resolution is 16mA / 4096 steps or
.003906 mA per step. So, 4096 86.4% = 3538.944 steps of 4096. Rounding off
3539 X .003906mA = 13.82422mA + 4mA = 17.82422mA output. Accuracy = 99.9988%.
PCL-2 Application examples
Electric Mode, Instantaneous kW example: Assume that 109.8kW was measured
as the current demand. Set the full-scale setting at 200kW. Output current
would be 109.8/200= .549 or 54.9% of full scale. If 200kW=16mA, then 16mA X
.549 = 8.784mA. 8.784mA + 4mA = 12.784mA. Since a 12-bit DAC is used on a
200kW full scale, the output resolution would be 16mA/4096 or .003906 mA per
step. Therefore 8.784mA/.003906= 2248.85 steps. Round down to 2249 .003906 =
8.7845 mA + 4mA = 12.7845mA. Accuracy would be 12.7845/12.784= 99.996%. The
value of 2248 is written to the DAC, which outputs a current of 12.7845mA.
Water Mode example (Gallons In, Gallons per Second Out): Assume that a
building has a maximum of 883GPM water flow. The equivalent (average) maximum
rate per second is 883/ 60=14.71667 GPS. The output desired is in Gallons per
Second so the output time interval is set to Seconds. Let’s set the Full Scale
Value at 16 GPS. Therefore, 16GPS = 20mA. 0 GPM = 4mA. Output flow rate
resolution would be 16GPS / 4096 or .00390625 GPS (or .02442% of full scale)
per step. Assume the water meter’s Pulse value is 10 Gallons / pulse. Suppose
that pulses being received at this moment in time are at a rate of one pulse
per 4 seconds and the flow is steady. 10 Gallons/4 seconds = 2.5 Gallons per
second. 2.5/16 = 15.625%. 15.625% x 16mA = 2.50 mA + 4mA = 6.50mA output.
Output resolution is 16mA / 4096 steps or .00390625 mA per step. So, 4096
15.625% = 640.0 steps of 4096. 640 X .003906mA = 2.49984mA + 4mA = 6.49984mA
output. Accuracy = 99.9975%. A value of 640 is written to the DAC which would
yield an output on the current loop of 6.49984mA.
Suppose the building’s flow resulted in 1 pulse per second. That would equal
10 gallons per second. 10G/16GPS = 62.50%. Calculated output is 62.50% X 16mA
= 10mA + 4mA = 14.0mA. .625 X 4096 = 2560.0 steps. 2560 x .003906= 9.99936 +
4mA 13.99936mA, representing a flow rate of 10 GPS.
Let’s assume that the building has 2 pulses per second, or 20 Gallons per
second. This would overrange the PCL-2 full scale of 16 GPS; The RED Error LED
D2 would light indicating an erroneous condition. Change the full scale a
number higher than 20.
Water Mode example (Gallons In, Gallons per Minute Out): Assume the same
building has a maximum of 883GPM water flow. The output desired is in Gallons
per Minute so the output time interval is set to Minutes. Let’s set the Full
Scale Value at 1000 GPM. Therefore, 1000GPM = 20mA. 0 GPM = 4mA. Output flow
rate resolution would be 1000GPM / 4096 or .002441GPM (or .02441% of full
scale) per step. Assume the water meter’s Pulse value is 10 Gallons / pulse.
Suppose that pulses being received at this moment in time are at a rate of one
pulse per 4 seconds and the flow is steady. 10 Gallons/4 seconds = 15 pulses
per minute = 150 Gallons per minute. 150/ 1000= 15.00%. No rounding required.
15% x 16mA = 2.40 mA + 4mA = 6.40mA output. Output resolution is 16mA / 4096
steps or .003906 mA per step. So, 4096 15% = 614.4 steps of 4096. 614.4 X
.003906mA = 2.3998mA + 4mA = 6.3998mA output. Accuracy = 99.9976%. A value of
614 is written to the DAC which would yield a current loop output of 6.3982mA
representing 150 gallons per minute.
Water Mode example: (Gallons In, Gallons per Hour Out)
Example: Assume that a building has a maximum of 883GPM flow rate. This
equates to 883 x 60 or 52,980 GPH. The output desired is in Gallons per Hour
so the output time interval is set to Hours. Let’s set the Full Scale Value at
60,000 GPH. Therefore, 60,000GPH = 20mA. 0 GPM = 4mA. Output flow rate
resolution would be 60,000GPH / 4096 or 14.6484GPH (or .02441% of full scale)
per step. Assume the water meter’s Pulse value is 10 Gallons / pulse. Suppose
that pulses being received at this moment in time are at a rate of one pulse
per second and the flow is steady. 10 Gallons/second = 60 pulses per minute
(or 3600 pulses/hour) = 36000 Gallons per hour. 36000/ 60000= 60.00% of full
scale. No rounding required. 60% x 16mA = 9.6 mA + 4mA = 13.60mA output.
Output resolution is 16mA / 4096 steps or .003907 mA per step. So, 4096 60%
= 2458 steps of 4096. 2458 X .003907mA = 9.6039mA + 4mA = 13.6039mA output.
Accuracy = 99.9713%. The PCL-2’s processor writes a value of 2458 to DAC which
would yield an output of 13.6039mA representing 36000 gallons per hour flow
rate.
Gas Mode examples:
These will be generally the same as water examples, but input and output units
must be the same. For example, if input value per pulse is in Cubic feet, then
the output must also be in cubic feet/unit of time selected. This could also
be in cubic meters in & cubic meters out/unit of time. The units don’t matter
as long as they are the same. There is no conversion of units in the PCL-2 for
Water and Gas applications. In an Electric application, there is a conversion
included for watthours in / kilowatts out. This is a unique situation and thus
has been addressed in the PCL-2’s program.
LED Indicators
LED Functions:
INPUT RED LED (D6): This LED lights each time a pulse is received from
the meter sending the pulses to the PCL-2, and thus the input is active. Short
input durations are often difficult to see, particularly on Water and Gas
meters. A bright RED LED is used to help mitigate this problem. OUTPUT GREEN
LED (D5): This LED flashes once per second for 100ms, indicating that the
PCL2’s microcomputer is writing an output value to the Current Loop Amplifier.
CONVERTER OPERATING PROPERLY (COP)/TEST-CALIBRATE MODE YELLOW LED (D1):
In Normal operational mode, LED D1 flashes for 100mS every 3 seconds simply to
show that the processor is alive and running through its program loop
correctly. When the PCL-2 is in either the Test Mode or Calibrate mode, LED D1
is lit continuously. When Test or Calibrate mode is exited, the D1 will resume
flashing once every 3 seconds.
ERROR RED LED (D2): This LED will light continuously to indicate that an
overrange error exists, generally that the Full Scale is too small or the
Pulse Value is too large. When this happens, the Full Scale will need to be
increased since the pulse rate is generally fixed and cannot be changed. USB
TX GRN LED (D9): This LED flashs when the USB port is sending data out of the
PCL-2 to the host computer running the SSI Universal Programmer.
USB Rx RED LED (D8): This LED flashs when the USB port is receiving data
from the host computer running the SSI Universal Programmer software or a
ascii terminal software program.
PCL-2 Wiring Diagram
PCL-2 4-20mA Current Loop Converter Module
Testing the PCL-2
Using a good quality (0.000V) Digital Volt Meter (DVM) which is capable of
reading very low voltages accurately, connect the leads across Resistor R14
above the current loop output connector. Alternately Test Points TP5 and TP6
can be used. Put the PCL-2 into the test mode.(See Page 9.) Yellow LED D1 will
light continuously. The PCL-2’s output must be connected to the receiving
device’s input and must be powered up, or connected to a suitable test setup.
The voltage across R14 is proportional to the output current. At 20mA of
output current, the output voltage across R14 will be .20VDC. At 4mA of output
current, the output voltage across R14 will be .04VDC. In test mode, the
output current will sweep from 4mA to 20mA in 10 seconds, and remain at 20mA
for 4 seconds. It will reset to 4mA for 4 Seconds and then repeat. Therefore,
your meter will climb from .04V to .20 V in 10 seconds, stay at .20V for 4
seconds, go to .04V for 4 seconds and then climb again from .04 to .20V. This
repeats continuously while in the test mode. While in Test Mode, the pulse
input is ignored and does not matter if it is connected or not. Take the PCL-2
out of test mode and return to Normal Operation mode. Connect electric meter’s
pulse output to the input of the PCL-2 if not already connected. Ensure that
the red LED next to the Yin terminal is on when the Y input line is low(has
continuity with the Kin terminal). Pressing any key on the keyboard while in
Test or Calibrate (DAC) mode will cause the PCL-2 to exit Test Mode or
Calibrate Mode and return to run mode.
Interfacing the PCL-2 to the Receiving Device
The receiving device must have an input suitable for accepting a 4-20mA
current, equipped with a 250 ohm precision resistor (1% or better), at a
maximum voltage of +5VDC. Use a #18AWG to #22AWG 2-conductor stranded control
cable between the PCL-2 and the receiving device. 4mA will yield 1VDC across
the 250 ohm resistor, while 20mA will yield 5VDC. Keep the cable length to the
minimum possible. Shielded cable is recommened with the shield connected away
from the PCL-2.
Programming
The PCL-2 requires you to connect to it via it’s USB port to a computer for
programming. See Page 5. Parameters that must be programmed are:
Operational Mode: General Purpose, Electric, Water or Gas
Output Time period: seconds, minutes or hours
Pulse Value, 1 to 99999 Watt-hours, Gallons or CCF per pulse
Input Debouncing Filter, 0.5, 1, 5, 20mS
Full Scale Value; Range 1 to 99999 pulses/sec, kW, Gallons/time, or CCF/time,
depending on mode of operation.
Output Mode selection, either Instantaneous or Average (Electric only)
Demand Averaging Interval (if the above selection is Average) 1-60 minutes
Test Mode or Calibration Mode, Enter and Exit
(*See special note on Pulse Value and Max Full Scale Value for General Purpose
Mode.)
Technical Support
Contact Brayden Automation Corp. Tech Support at 888-BRAYDEN
(970-461-9600) if you need technical
support.
Programming the PCL-2 4-20mA Current Loop Converter Module
Software Required
The PCL-2 is programmed using SSI’s Universal Programmer software, available
as a free download on the SSI website at
www.solidstateinstruments.com/downloads.
Download the software version V1.xxx (TBD) or later from the
solidstateinstruments.com website. See Page 10 for instructions on installing
the SSI-UP software.
For subsequent programming after it has been set up the first time, follow
these instructions:
Using the USB programming cable that accompanied the PCL-2, plug the “B” end
into the PCL-2. Plug the “A” end into your computer’s USB port. Do this first
and apply power to the PCL-2 before startiing the SSI-UP programming software.
Run the SSI Universal Programmer software. The SSI-UP software should
automatically recognize that a PCL-2 is plugged into the computer and open the
PCL-2 programming page. The current programming parameters will be read from
the PCL-2 and displayed in the PCL-2 window. To READ all parameters back from
the PCL-2 at any time, click on the
To program a new setting into the PCL-2, enter the desired value in the
appropriate box in the window and click on
Operation Mode: Pull down the pull-down menu and select the type of
application, General Purpose, Electric, Water, or Gas. Depending on the mode
selected, certain features may be grayed out which are not compatible with the
mode selected.
Pulse Value: Enter the Form A (2-wire) pulse value in the selected units
for the mode, with a number from 1 to 99999. Electric is watthours, Water is
gallons, Gas is in Cubic Feet. For General Purpose mode the pulse value is 1
and cannot be changed. (For Electric, you will need to multiply the kWh value
by 1000 to get the watthour value.) You may not enter a decimal point. The
value must be in whole (integer) numbers. For example, if your Form A (2-Wire)
value is .144 kWh/pulse, then your watthour value per pulse is 144wh/ p.
Enter 144 in the Pulse Value box. Click on
Full Scale: Enter the desired full scale value from 1 to 99999 to the
desired Full Scale KW, Gallons or Cubic Feet. For General purpose mode, the
maximum full scale value range is dependant on Time Integral selected. For
Seconds, 1-100, Minutes 100-10000, and Hours 10000-1000000. This gives you the
flexibility to enter a value that will work with the 12-bit resolution with
the receiving telemetry. For example, enter 500 for a for 500kW full scale
value. Click on
Time Integral: Pull down the pull-down menu and select Seconds, Minutes
or Hours. This period is the time over which the current output represents the
usage or flow rate. This setting is not used in Electric mode.
Output Mode: Select Instantaneous or Average for the Output Mode. In
Instantaneous Mode, the the 4-20mA output
will be updated each second with the current readings result. In Average Mode,
the calculated average will be written to the output amplifier for the
averaging interval selected. Click on
Average Interval: Select the desired Averaging Interval from 1 to 60
minutes (if the Output Mode selection is Average). 15 minutes is the default
since most electric meters use a 15-minute demand averaging interval. This
setting is not used if you are operating in the Instantaneous Output mode.
Click on
Input Debounce: Select the debounce time in milleseconds, either .5, 1,
5, or 10 milleseconds. This is the time that an active input must be present
at the input before it is qualifiied as a valid pulse. This is a filtering
technique to filter out notice and prevent noise on the input line from appear
to be a pulse. Shielded cable from the meter is also recommended to reduce
noise. Tie the shield to the ground at the meter to shunt noise away from the
PCL-2.
When changing system settings is complete make sure to click on <Save
Parameters>. All parameters will be saved in non-volatile EEPROM memory.
EEPROM memory uses no battery for backup so all parameters will never be lost.
Data retention is typically 10 years in absence of power.
Test Mode: Select On or Off: Selecting On sets the PCL-2 in test mode and
begins a sweep from 4mA to 20mA in 10 seconds. It will remain at 20mA for 5
seconds, then reset to 4mA for 5 seconds. It will start again and repeat this
sequence continuously until either Off
Calibration Mode: To Calbrate the PCL-2’s output with your regulated
24VDC power supply, turn off Test Mode, and set the Calibration mode to On.
Turn on your 24VDC loop power supply.
– Set 4mA Low setpoint: Select the DAC0 radio button. This sets the output at
4mA. Use your volt meter to read the voltage across R14. Adjust Pot R16 until
the volt meter reads .040VDC.
– Set 20mA Full scale: Select the DAC4095 radio button. This sets the output
at 20mA. User your volt meter to read the voltage across R14. Adjust Pot R15
until the volt meter reads .200VDC.
– Check mid-scale: Select the DAC2047 radio button. This will set the output
at 12mA. The volt meter should read a voltage of approxiately .120VDC. Use
calibration “goop” on the pots R15 and R16 to prevent them from moving.
– Any character being sent over the USB interface will exit the Test Mode.
Set Factory Defaults: In the event that you want to reset all PCL-2
settings to the factory defaults, select Reset Parameters and Click on <Save
Parameters>.
Read Firmware Version: To read the firmware version is listed on the page
when the SSI Universal Software connects to to the PCL-2.
Read Parameters: Click on
Technical Support
Contact Brayden Automation Corp. Tech Support at
970-461-9600 if you need assistance on
the application of the PCL- 2 4-20mA Pulse to Current Loop Converter Module.
Installing the SSI Universal Programmer software
Installation Procedure
-
Download the software at www.http://solidstateinstruments.com/sitepages/downloads.php
If your computer is a Windows 7 32-bit machine select that file. If your computer is Windows 7 64-bit or Windows 10, select the regular download file. -
Make a file folder called “SSI Universal Programmer” and copy the SSIUniversalProgrammer.msi file into this folder.
-
Doubleclick on the SSIUniversalProgrammer.msi file to begin the installation of the program.
-
Follow the directions on each box that will install drivers and get the program ready to use.
-
When done click “Finish” and close the Installation window(s).
-
Connect the PCL-2 to your PC with the Type A-B USB cable and power up the PCL-2.
-
Double click on the SSI logo ICON on your desktop to start the program.
-
The SSI Universal Program window should open with the correct boxes for the PCL-2 settings. Follow the directions on Page 5.
SSI UP Screen shot
Programming using ASCII Text Commands
The PCL-2 may be also be programmed using a Terminal program like TeraTerm,
Hyperterminal, ProComm or almost any Ascii terminal program. Parameters are
57600
baud, 8 data bits, 1 stop bit, no parity, no flow control. Upper or lower case
does not matter.
Commands are as follows:
‘H’,’h’ or ‘?’ for a list of all commands.
‘MX
‘DX
‘PXXXXX
‘FXXXXX
‘IX
‘CX'
‘iXX
‘TX'
‘T
‘rm
‘Z
‘V
‘DACXXXX
Set to ‘DAC0 for 4mA (Enabled 5 min.)
Set to ‘DAC4095
Set to ‘DAC2047
Full Scale Value Setting Range for General Purpose Mode
For Electric, Water and Gas, the Full Scale Value is 1-99999. However, in
General Purpose
Mode, the Full Scale Value varies with the Output Time Integral:
If Time Integral(m) is set to Seconds, the range of Full Scale Value is 1-100;
If Time Integral(m) is set to Minutes, the range of FullScale Value is
100-1,0000;
If Time Integral(m) is set to Hours, the range of FullScale Value is
1,0000-1,000,000.
Brayden Automation Corp.
6230 Aviation Circle
Loveland, CO 80538
(970)461-9600
support@brayden.com
www.solidstateinstruments.com