Vencon UBA Series User manual

UBA External Devices Manual
by Marc Venis P.Eng.
President
Vencon Technologies Inc.
updated for UBA5 Software version 1.50 December 2013
Changes:
Dec 2013, for U A Console rev 1.50
ExtVAmp: model 3 added for external amplifier that shares the U A's ground with the negative input
Dec 2012 for U A Console rev 1.30
Added:
ExtChargeDevice: similar to ExtLoadDevice
ExtChargeControl: similar to ExtChargeDevice
ExtSensor: general case of ExtThermistorRabcd and ExtTempProbe
U A External Devices Manual Page 1 of 46 Vencon Technologies Inc.

Table of Contents
Changes: ................................................................................................................................................... 1
Introduction ....................................................................................................................................................... 4
Using a Resistor as an External Load ............................................................................................................... 5
Method 1 - Manually Connect a Power Resistor .......................................................................................... 5
Example for manually calculating capacity .............................................................................................. 6
Method 2: Manually Connect a Power Resistor and Specify Its Resistance ............................................... 6
Calibration File Modifications .................................................................................................................. 6
Method 3 - The U A Controls the Load Resistor ........................................................................................ 7
Controlling the Load with Direct Digital Drive ....................................................................................... 7
Controlling The Load With Optically Coupled Drive .............................................................................. 7
Controlling The Load with A Relay ......................................................................................................... 8
Calibration File Modifications For a Switched Resistive Load .................................................................... 8
Testing With The attery Connected to The Accessory Port ....................................................................... 9
Combined Channels .................................................................................................................................... 10
Using an Active Load as an External Load .................................................................................................... 11
Controlling the Active Load ....................................................................................................................... 11
Calibration File Modifications For an Active Load .................................................................................. 11
Uncontrolled Constant Current Load with no Current Measurement .................................................... 12
Uncontrolled Load with Current Measurement ...................................................................................... 12
Controlled Constant Current Load with no Current Measurement ........................................................ 13
Controlled Load with Current Measurement .......................................................................................... 13
Resistive Load Described As an Active Load ........................................................................................ 13
Using a Non-Linear Load as an External Load .............................................................................................. 14
Running U A Console with an External Load .............................................................................................. 15
Step 1 - Verify that U A Console has read any external devices in the calibration file. ........................... 15
Step 2 - Verify that the calibration lines and set-up are correct. ................................................................ 16
Step 3 - Run a attery Analysis .................................................................................................................. 16
U A Load Monitoring ................................................................................................................................... 18
Using a Resistor as a Load Current Sensor ................................................................................................ 18
Warning .................................................................................................................................................. 19
Using a U A to Test a attery Charger ......................................................................................................... 22
Important Note ........................................................................................................................................ 22
Warning: ................................................................................................................................................. 22
Monitoring Charger Voltage and Current ................................................................................................... 22
Considerations for Monitoring Charger Performance ................................................................................ 24
Pulsing Charge Current ........................................................................................................................... 24
attery Voltage Error Due to Sense Resistor ......................................................................................... 24
Running U A Console to Monitor Charger Voltage and Current ............................................................. 25
Using an External Charger In a Charge/Discharge Cycle .......................................................................... 26
Vencon High Current Load Module ............................................................................................................... 28
Appendix A - U A External Device Reference ............................................................................................. 29
External Loads & Chargers ........................................................................................................................ 29
External Load Devices ................................................................................................................................ 29
ExtLoadDevice Syntax: .......................................................................................................................... 29
ExtLoadDevice Examples ...................................................................................................................... 31
External Charge Devices ............................................................................................................................ 32
ExtChargeDevice Examples: .................................................................................................................. 33
Analog Input "-4" - Charger Voltage Channel ....................................................................................... 33
External Load Control ................................................................................................................................ 34
ExtLoadControl Syntax: ......................................................................................................................... 34
ExtLoadControl Examples ...................................................................................................................... 35
ExtChargeControl Syntax: ...................................................................................................................... 35
External attery Voltage Amplifier/Attenuator ......................................................................................... 36
attery Voltage Amplifier/Attenuator Syntax: ....................................................................................... 36
U A External Devices Manual Page 2 of 46 Vencon Technologies Inc.

ExtVAmp Examples ............................................................................................................................... 37
External Sensor ........................................................................................................................................... 38
External Temperature Sensor – Voltage Output ......................................................................................... 38
External Thermistor Sensor ........................................................................................................................ 38
External Sensor – The General Case .......................................................................................................... 39
Accessory Analog Input ............................................................................................................................. 41
Appendix - U A Accessory Port1 & Port2 ................................................................................................ 43
Accessory Port 1 Pinout: ........................................................................................................................ 43
Accessory Port 2 Pinout: ........................................................................................................................ 44
Notes: ...................................................................................................................................................... 44
Appendix C - U A Accessory Port1 Optoisolated Output ............................................................................ 45
Accessory Port 1 Optoisolated Pinout: ................................................................................................... 45
Notes: ...................................................................................................................................................... 45
Footnotes: ....................................................................................................................................................... 46
Accessory Port 2 ..................................................................................................................................... 46
Future Upgrades ...................................................................................................................................... 46
ExtLoadDevice Syntax: .......................................................................................................................... 46
ExtLoadControl Syntax: ......................................................................................................................... 46
U A External Devices Manual Page 3 of 46 Vencon Technologies Inc.

Introduction
This manual describes the use of external devices with your U A (both U A4 and U A5).
The U A itself is a very versatile battery analyzer. ut to make it even more versatile, we’ve included two
accessory ports that can be used to connect to external instruments. This manual shows you how to use the
first accessory port and one bit from the second accessory port.
This manual describes how the U A can use external loads, chargers, voltage amplifiers, current and
temperature sensors. With these devices, you can greatly expand the functionality of the U A.
The appendixes include the format for describing the external devices in the calibration file and a
description of the accessory port.
U A External Devices Manual Page 4 of 46 Vencon Technologies Inc.

Using a Resistor as an External Load
You may want to use a resistor instead of the U A’s internal load as a load for battery testing. Here are
reasons why:
1. You require a load current greater than that which the U A can supply. For example, you want to
discharge a battery at 10A. You could buy two or three U As and combine their channels, but a
power resistor is generally less expensive.
2. You require a load current less than that which the U A can supply. For example, you want to
discharge a small “button” size battery. You can buy a U A modified with its load current
controllable down to less than a milliamp, but a resistor is less expensive.
3. You want to discharge a primary battery with a resistor to test to the ANSI specification.
4. You want to discharge the battery down to 0V, match the intended load, or monitor the charge or
discharge current of a battery in situ.
Method 1 - Manually Connect a Power Resistor
The simplest way to use a resistor as a load is to connect it to the battery and then start a battery analysis.
The U A then acts as a data logger.
UBA4
Battery
being tested
-
+
RESISTOR
O TIONAL SWITCH
X
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Adding a switch makes it easier to connect the load to the battery and start the battery analysis
simultaneously. For the battery analysis, use a battery analysis routine ( AR) with a load current of zero
and a cut off voltage of zero (or just use the data logger AR). U A Console will record the voltage while
the battery is being discharged. You can calculate the load current by dividing the battery voltage by the
load resistance and you can calculate the battery capacity by integrating the current. You can integrate the
current by importing the test results into a spread sheet and creating a column with the load current (in
milliamps) where each cell is calculated by dividing the voltage by the load resistance. Create a delta
capacity column beside the current column where each cell is the current multiplied by the time between
rows (in hours). The sum, shown in the delta capacity column, is the capacity (in mAh).
Example for manually calculating capacity
Time (hours) Voltage Current (mA) delta capacity
T0 (start time)
T1V1I1 = V1/R * 1000mA C1 = I1 * (T1 – T0)
T2V2I2 = V2/R * 1000mA C2 = I2 * (T2 – T1)
….
TNVNIN = VN/R * 1000mA CN = IN * (TN – TN-1)
Total: C1 + C2 + … + CN
The problem with using this method for rechargeable batteries is that the battery isn’t automatically
disconnected when it reaches its cut-off voltage, this may overdischarge and damage it, and U A Console
doesn’t give a current during the test nor a capacity afterwards – you have to do this manually. An
improvement on this test is to specify the resistance of the load you’re using, which brings us to the next
method.
Method 2: Manually Connect a Power Resistor and Specify Its
Resistance
If U A Console knows the value of the load resistor, it can not only calculate the load current and display
it during the battery analysis, it can also display the capacity discharged in real time and record the final
capacity. U A Console uses the resistor value to calculate the load current and capacity.
Calibration File Modifications
The U A Console receives the value of the load resistor from the U A calibration file.
The load resistor is specified as an external load device as follows:
ExtLoadDevice: name 3 resistance max_pwr
Where
name is a name you give the resistor
‘3’ is the model number for a resistor
resistance is its resistance in ohms
max_pwr is the maximum power in Watts that the resistor can dissipate (use 0 for no limit).
Example, a 5 Ohm 2W resistor.
*ExtLoadDevice: name model resistance limit <- this is a comment line
ExtLoadDevice: Resistor5R 3 5 2
For further details, consult the UBA External Device Reference in Appendix A.
For this method you have to manually connect and disconnect the load resistor, in the next section we show
how to have the U A do this for you.
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For maximum accuracy we suggest that you have the U A’s battery leads connect across the resistor load
and switch if used and then run wires from the resistor to the battery. This way U A Console will use the
voltage across the resistor to calculate the load current and, if you specify the wire resistance from the
battery to the load, will display the battery voltage with the voltage drop removed.
Method 3 - The UB Controls the Load Resistor
With this method, U A Console connects the resistor load at the beginning of the discharge cycle and
disconnects it afterwards. It requires something to connect and disconnect the load, such as the Vencon
HCLM (high current load module), the Vencon Relay Module or you can build your own load controller
using the output from the accessory port as described below.
Controlling the Load ith Direct Digital Drive
This circuit requires only one FET. You can use this circuit if you have access to the accessory port, either
on the U A PC (available if no other accessory port 1 accessories are used) or via a connector mounted
on the back of your U A (if ordered with your U A).
CONTROLLING THE LO D WITH DIRECT DIGIT L DRIVE
BATTERY
BEING TESTED
DIGIT L OUPUT FROM
UB CCESSORY PORT
3 2
RESISTOR
LOAD
TO UB - B TTERY INPUT
TO UB + B TTERY INPUT
LOAD SWITCH
The digital output directly drives a FET. A logic level FET is recommended because the maximum output
of the U A is 5V (no load). A logic 1 on the accessory port output connects the load resistor. Try to use a
digital output that has a default (reset) low value (DO1 or DO0 on U As with firmware 13 or later) so that,
after reset, the load is switched off.
Controlling The Load With Optically Coupled Drive
If you have an opto-coupled accessory output (the Vencon DODOTP use this circuit. It requires 8 to 15
Volts (or less if you use a logic level FET). You can use an external power supply, the battery being tested
(if its voltage is high enough), or a small 9V battery. Although this circuit is a bit more complicated than
the direct-drive circuit, it isolates the switch from the U A and is best when using high current loads. Try
to use a digital output that has a default (reset) low value (DO1 or DO0 on U As with firmware 13 or later)
so that, after reset, the load is switched off.
U A External Devices Manual Page 7 of 46 Vencon Technologies Inc.

TO UB - B TTERY INPUT
TO UB + B TTERY INPUT
+12V
LOAD SWITCH
RESISTOR
LOAD
BATTERY
BEING TESTED
CONTROLLING THE LO D WITH OPTIC LLY COUPLED DRIVE
1M
DIGIT L OUPUT FROM
UB CCESSORY PORT
Controlling The Load ith A Relay
This circuit uses the digital output to control a relay. Choose a relay to control a high current or because its
contacts are isolated from the U A, to control an external charger.
2N3904
TO UB - B TTERY INPUT
TO UB + B TTERY INPUT
CONTROLLING THE LO D WITH REL Y
+12V
1N4001
3 2
2k2
BATTERY
BEING TESTED
DIGIT L OUPUT FROM
UB CCESSORY PORT
RESISTOR
LOAD
RELAY
4
3
1
2
Calibration File Modifications For a Switched Resistive Load
The format for a switched resistive load is similar to an unswitched load, with the difference being an
additional ExtLoadControl field.
ExtLoadDevice: name 3 resistance max_pwr ExtLoadControl
Where,
name is a name you give the resistor
‘3’ is the model number for a resistor
resistance is its resistance in ohms
max_pwr is the maximum power in Watts that the resistor can dissipate (use 0 for no limit)
ExtLoadControl is the name of the device that connects or switches the resistor in and out.
The external load control is specified in a line right after the “ExtLoadDevice” line as follows:
ExtLoadControl: name 2 dochan_on dochan_off maxamps
Where,
name is a name that you give this control
‘2’ is the model number for an electronic switch or relay
dochan_on and dochan_off are the digital output channels that turn the load on and off
maxamps is the maximum current that this control can support.
The dochan_on or dochan_off entry is expressed in the form: “…dcba” where each letter represents a
output line, i.e.: “a ” represents accessory digital output 0, “b” represents digital output 1, “c” the digital
output 2 on the 2nd accessory port located on the 2nd accessory port and “d” controls the fan. Setting the
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digit to “x” means no change; to “1” means set the line high; and to “0” means set the line low.
dochan_off can also have a value of “!” which means the opposite of dochan_on (which is normally what
you want).
Example 1:
A 1 Ohm 100W resistor controlled by a FET driven directly by the accessory digital output line ‘1’ where
a high on this line turns the FET on would be specified as follows:
*ExtLoadDevice: name model resistance limit ExtLoadControl
ExtLoadDevice: Resistor1R.1 3 2 100 Resistor1RSW
*ExtLoadControl name model dochan maxamps
ExtLoadControl: Resistor1RSW 2 1x ! 10
Notes:
specifying the ExtLoadControl controlling the ExtLoadDevice (“Resistor1RSW” in the above
example) tells U A Console that this resistor is controlled and there’s no load current if the
ExtLoadControl is off;
the dochan of “1x !” means that setting digital output ‘1’ high turns on the load and setting it low turns
off the load;
an exclamation mark (explained later) is not used after ExtLoadControl because digital output ‘1’ is set
low after reset (but adding the exclamation mark won’t hurt).
Example 2:
Our 1 Ohm 100W resistor is now controlled by a FET driven by the accessory digital output line ‘0’ where
a high on this line turns the FET on:
*ExtLoadDevice: name model resistance max_amps ExtLoadControl
ExtLoadDevice: Resistor1R.2 3 2 10 OptoSwitch
*ExtLoadControl name model dochan maxamps
ExtLoadControl!: OptoSwitch 2 x1 ! 3
Notes:
the dochan of x1 means that setting digital output ‘0’ high turns on the load;
we’ve added an exclamation mark (!) after ExtLoadControl, to instruct U A Console to set this
control OFF (i.e. digital output ‘0’ low) after initializing the U A. This is necessary for U A5
firmware revisions prior to 13 because digital output ‘0’ is set high after reset and will remain that
way until the ExtLoadControl! line is read in the calibration file.
For further details, consult Appendix A.
Testing With The Battery Connected to The ccessory Port
The U A supports using the accessory analog input to measure the battery voltage. The external amplifier
might be a high impedance amplifier for electrochemical research or a high voltage attenuator (amplifier
with negative gain) for testing high voltage batteries.
You can use a resistor load when using an external amplifier for the battery voltage. In that case, the
external resistor load is assumed to be connected to the battery, and not the voltage going into the U A's
battery input.
For example:
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*ExtV mp: name model aichan Vin0 Vout0 … Vin_n Vout_n
ExtV mp: 10x mp 2 0 0.0 0.0 0.1 1.0
*ExtLoadDevice: name model resistance limit
ExtLoadDevice: Resistor5R 3 5 2
In this example we use an amplifier with a gain of ten and a 5 Ohm resistor. If the battery voltage is
100mV the voltage going into the external analog input will be 1V. U A Console will calculate 20mA as
the current through the 1 Ohm resistor.
Combined Channels
You can use an external resistor with combined channels. You may want to combine channels to increase
the charge current, but still use a resistor for the load. In that case, U A Console uses the voltage that is
displayed when calculating the resistor load current. It works if you are using the average of all the
combined channels (default) or you are selecting one of the battery inputs as the battery voltage.
If you prefer to use a different voltage for calculating the resistor current, you can use an external load
device model 2 to describe the resistor. That model allows you to specify the source from which to sample
the voltage used to calculate the load current.
For example, if you combine channels and specify -2 for the analog channel, it will use the battery voltage
from the first channel in the combined channel:
*ExtLoadDevice: name model in do Ro limit control Iin Vin ...
ExtLoadDevice: Model2 in-2 4 -2 x 0 0 <none> 10 1
For example, if you combine channels and specify -3 for the analog channel, it will use the battery voltage
from the displayed voltage:
*ExtLoadDevice: name model in limit control Iin Vin ...
ExtLoadDevice: Model2 in-3 2 -3 0 <none> 0 0 10 1ExtLoadDevice:
U A External Devices Manual Page 10 of 46 Vencon Technologies Inc.

Using an Active Load as an External Load
You can program your U A to control an active load instead.
Your U A can turn on the active load at the beginning of the discharge cycle, measure the load current (if
the active load has an analog output signal), and turn it off at the end of the cycle.
Controlling the ctive Load
The U A uses the digital output on the accessory port to control the active load. If the active load has a
voltage output that represents the load current, the U A can monitor it using the analog input on the
accessory port. The following is the way the active load should be set up:
Battery
Being
Tested
-
+
UBA4
ACTIVE
LOAD
Accessory ort:
Digital Output &
Analog Input
Note, the U A is connected to the Active Load and not to the battery. This is done for two reasons. First
this reduces the ground potential difference between the U A and the active load which would interfere
with the control and measurement of the active load. And second U A Console assumes that it’s
measuring the voltage across the load and, if requested by setting the external resistance, can compensate
for the voltage drop from the load to the battery.
Calibration File Modifications For an ctive Load
The ExtLoadDevice line, in the calibration file, describes if the U A controls the ExtLoadControl line.
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The ExtLoadDevice line specifies the type of load (constant current or constant resistance), the load current
or resistance, and whether it’s controlled. The ExtLoadControl line specifies how the load is controlled
(only on or off are currently supported).
These lines are specified as follows:
ExtLoadDevice: name aichan do Ro limit control Iin0 Vout0 … Iin_n Vout_n
ExtLoadControl!: name 2 dochan_on dochan_off limit
Where for the ExtLoadDevice:
name is a name you call the device
2 is the model number for a general load
aichan is the analog input channel that this device connects to on the U A
do is the state digital of the digital lines to optionally enable or select this device.
Ro is the output resistance of the device
limit is the maximum load current
control is the name of the external load control that controls this device
Iin0 Vout0… describe the I-V characteristics of the device.
and for the external load control:
name is a name you call the control
2 is the model number for an electronic switch
dochan_on and dochan_off are the digital output channel on and off settings
limit is the maximum current.
For further information see Appendix A.
Depending on the type of load you have, there are a number of possible ways to program it, as shown
below.
Uncontrolled Constant Current Load ith no Current Measurement
If your active load isn’t controlled (i.e., is always on) and does not have a measured current output, you
need only to specify the ExtLoadDevice with no analog input.
Example – 10A load.
*ExtLoadDevice: name model aichan do Ro limit control Iin0 Vout0
ExtLoadDevice: CCLoad1 4 -1 x 0 0 <none> 10 0
This specifies an ExtLoadDevice called CCLoad1 that doesn’t measure a current output signal (the “-1”),
isn’t controlled by an ExtLoadControl (the “<none>”), has no current limit (the “0”), and is always 10A.
Uncontrolled Load ith Current Measurement
If your load isn’t controlled, but does have an output voltage representing the load current you need only an
ExtLoadDevice line in the calibration file.
Example:
*ExtLoadDevice: name model aichan do Ro limit control Iin0 Vout0
ExtLoadDevice: CCLoad2 4 1 x 0 0 <none> 10 1
This specifies an ExtLoadDevice called CCLoad2 with an output voltage signal representing load current.
This signal is connected to accessory input 1 and a 10A load current gives an 1V signal (U A Console
assumes 0A gives 0V, thus an effective resistance of 0.1R).
U A External Devices Manual Page 12 of 46 Vencon Technologies Inc.

Controlled Constant Current Load ith no Current Measurement
If your active load is controlled (i.e., can be turned on and off) but has no voltage output representing
current, you need an ExtLoadDevice and ExtLoadControl line in your calibration file.
Example:
*ExtLoadDevice: name model aichan do Ro limit control Iin0 Vout0
ExtLoadDevice: CCLoad3 4 -1 x 0 0 CCSwitch3 10 0
*ExtLoadControl name model dochan maxamps
ExtLoadControl: CCSwitch3 2 x1 ! 20
This specifies an ExtLoadDevice called CCLoad3 with no current signal output, and no current limit. It
draws 10A when turned on. An external load control called CCSwitch3, which turns on the load by putting
a digital high on digital accessory output 0 and can control up to 20A, is also specified.
Controlled Load ith Current Measurement
You will need an ExtLoadDevice and ExtLoadControl line in your calibration file.
Example
*ExtLoadDevice: name model aichan do Ro limit control Iin0 Vout0
ExtLoadDevice: CCLoad4 4 0 x 0 0 CCSwitch4 100 1
*ExtLoadControl name model dochan maxamps
ExtLoadControl!: CCSwitch4 2 1x ! 20
This specifies an ExtLoadDevice called CCLoad4 with analog current signal on accessory input 0 that’s
controlled by CCSwitch4, has no current limit, and has 1V for 100A of current (effective resistance of
10mR).
An ExtLoadControl called CCSwitch4 which turns on the load by putting a digital high on digital accessory
output 0 and has a 20A current limit, is also specified.
Resistive Load Described As an Active Load
For a resistive load it’s possible to specify a model of 2 (general load instead of 3 for resistor) and specify
the I-V characteristic of a resistor. As an example:
*ExtLoadDevice: name model aichan do Ro limit control Iin0 Vout0
ExtLoadDevice: RLoad 4 -3 x 0 0 RSwitch 1 2
*ExtLoadControl name model dochan maxamps
ExtLoadControl!: RSwitch 2 x1 ! 20
This specifies an ExtLoadDevice called RLoad with analog current signal on the battery input (which is
what happens when a resistor is used) that’s controlled by RSwitch, has no current limit, and has an output
of 2V at a current of 1A (resistance of 2R).
An external load control, RSwitch, turns on the load by putting a digital high on digital accessory output 0
and has a current limit of 20A.
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Using a Non-Linear Load as an External Load
What about if you have a non-linear load, for example a light bulb or an electronic device. You can’t
describe it as a resistor which is linear. You probably thought that you can’t describe it as an active load,
because it isn’t. ut you can. Here’s how. Say for example you have a light bulb as a load. We measured
one at various voltages and got the following table and graph.
V (V) I ( )
0 0
0.2 0.35
0.5 0.55
1 0.68
2 0.87
3 1.04
4 1.18
5 1.32
6 1.44
7 1.56
8 1.66
9 1.76
10 1.86
11 1.95
12 2.04
13 2.14
From the graph you can see that the V-I curve not straight. ut you can describe the light bulb fairly
accurate by a series of linear line segments. We do that by coping the data directly from the V-I table
above ( reversing the V and I numbers) into the I-V description of the external load device. We get the
following line:
*ExtLoadDevice: name model aichan do Ro limit control Iin0 Vout0
ExtLoadDevice: Lamp 4 -2 x 0 0 <none> 0 0 0.35 0.2
0.55 0.5 0.68 1 0.87 2 1.04 3 1.18 4 1.32 5 1.44 6 1.56 7 1.66 8 1.76 9
1.86 10 1.95 11 2.04 12 2.14 13
Note, the line in the above example wraps around, but in the calibration it doesn't.
Another way to handle a non-linear load is to simply measure the load current. See the section “Using a
Resistor as a Load Current Sensor” for an explanation.
U A External Devices Manual Page 14 of 46 Vencon Technologies Inc.
V vs I for a 12V Lamp
0
0.5
1
1.5
2
2.5
0 5 10 15
Volts
Amps

Running UBA Console with an External Load
When you start a battery test you have to specify that you are using an external load device and it has to be
specified in the AR. egin by making sure you’ve added the correct lines to your calibration file and that
everything is set up correctly.
Step 1 - Verify that UB Console has read any external devices
in the calibration file.
In the channel selector, right click on your U A (Unit1 is this example) and select “Show this U A”.
(Note, this is for the version 1.10 and later of U A Console, for earlier versions view U A Network)
You will get the U A window. Click on Accessories and the following window will appear:
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Step 2 - Verify that the calibration lines and set-up are correct.
Close these windows and open a Multitester: choose the External Load tab then choose an external load
device. If you have a external load control select it and turn it on by clicking on the “On” button. If the
battery and load are connected, you should see the measured current displayed (you may have to wait a few
seconds).
Step 3 - Run a Battery nalysis
efore you can run a battery analysis, you must make a battery analysis routine ( AR) that uses the
external device and control. Open an existing or a new AR and choose or create the load action that’s to
use the external load. Choose Primary for the external load device (and for the external load control if you
have one) as shown below.
Save the AR and start a battery analysis. Click on the External Load tab and choose the external load
device to use as the primary load device and similarly for the external load control.
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Now start the battery analysis. When the discharge action with an external load specified starts, the load
will be connected (if an external load control is used) and the load current calculated and displayed.
If you have more than one external load device or external load control, call one the primary and the other
the secondary. You can control up to three devices and three controls in one battery test.
U A External Devices Manual Page 17 of 46 Vencon Technologies Inc.

UBA Load Monitoring
This describes the ways to use an external resistor to sense load current. This is an advanced application
and is meant only for esoteric battery testing applications.
Using a Resistor as a Load Current Sensor
When using an external load resistor with your U A you normally connect the resistor to the load (with or
without a control mechanism). ut you can also use a resistor to measure load current. Use the following
set up:
UBA4
Battery
being tested
-
+
External Load
CURRENT FLOW
+-
Current Sense Voltage
Accessory Analog Input
Notice that the resistor is in series with the battery and an external load. The U A can measure the voltage
across this resistor to calculate the load current.
Connect the current sense voltage to the analog input on the accessory connector and the U A will use it as
the load current. This works only when using an external load, not the U A’s internal load.
Since the U A is measuring the voltage across the battery (and not the external load) use a value of 0 for
the external wire resistance.
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Warning
The accessory port is not protected against ESD (electrostatic discharge) nor voltages outside the range
from 0 to +5V. The U A warranty does not cover damage to the accessory port.
If you’re using this set-up with a 0.5 Ohm sense resistor, you would add this to your calibration file:
*ExtLoadDevice: name model aichan do Ro limit control Iin0 Vout0
ExtLoadDevice: CurrentSense 4 1 x 0 10 <none> 1 0.5
ecause the resistor is being used to sense the current and not as the load, we have to use a general load
(model 2). Doing so enables us to specify that the accessory port monitors the current sense voltage. In
this example we’ve specified an “aichan” of 1, which is accessory port 1 analog input ‘1’.
If you want to use an current sense resistor, but don’t have any accessory connector installed specify a
combined channel U A and use the channel 1 input to measure the current sense voltage and channel 2
input to measure the battery voltage. Use the following set-up:
UBA4
Battery
being tested
-
+
External Load
CURRENT FLOW
+-
Current Sense Voltage
This set up isn’t as accurate as connecting the current sense voltage to the accessory input because the low
voltage range of the battery input is 0 to 7V, or almost one third less sensitive then the accessory input. ut
the battery voltage input is more accessible and better protected against over-voltage.
For this set up add to the calibration file:
U A External Devices Manual Page 19 of 46 Vencon Technologies Inc.

*ExtLoadDevice: name model aichan do Ro limit control Iin0 Vout0
ExtLoadDevice: CurrentSenseCh1 4 -2 x 0 10 <none> 1 0.5
Here we specify ‘-2’ as the aichan, which means that the resistor voltage is applied to the actual physical
battery input (which in a combined channel set-up is the first battery input). Set up the U A to use
combined channels 1 and 2 and specify that channel 2 is to be used for the battery input (so it doesn’t
average channel 1 and 2). Now the virtual U A will be using channel 2 for the battery voltage and channel
1 for the current.
With either of these set ups, the load current will be monitored and recorded with the battery voltage. To
use this in a battery test you need to select the current sense resistor for the load current. First make a
battery analysis routine ( AR) and specify “Primary” for the external load device, as shown below:
Then when starting a battery analysis, specify this AR and choose “CurrentSenseCh1” for the primary
load device as shown below. The battery analysis will interpret the sense resistor current as the load
current.
U A External Devices Manual Page 20 of 46 Vencon Technologies Inc.