Aside from the computer-connected interfaces, the BA6010 is also capable of remote-control operation without involving a computer. This is achieved through the handler interface, which is intended to connect to an automated cell handling equipment, providing and receiving logic signals to control its operation.
Handler Interface Documentation
Of all of the BA6010’s features, the handler interface proved to be the least well documented aspect. The only information is provided within three pages of the manual, with a lot of specifications and design specifics omitted and consistency errors in the information. For example, the table refers to an /ALARM signal which doesn’t exist in the pin-out. Another is the claim that COM1 is “The reference ground for external power EXTV1” where no such signal exists – presumably they mean EXT_DCV1. Likewise, the COM2 claim that it is “The reference ground for external power EXTV2” presumably means that of EXT.DCV2 – note the period rather than underscore. The language used is also ambiguous – EXT.DCV2 is claimed to be “The DC provider pin for the optoelectronic coupling signal.” Is it a source or a sink? Further to this, there are missing details – such as the voltages or currents that each pin is able to carry.
I made contact with B&K Precision over these frustrations and they were able to inform me that they are using TLP291-4 parts for the open-collector “inputs” which have absolute-maximum (not recommended) ratings of 80V and 50mA. While this was somewhat more useful information, it still didn’t address the bulk of my concerns. The only way around this would probably be to run my own experiments.
Handler Interface Connection
One of my bigger frustrations with the BA6010’s design is the choice of the Centronics 36-pin connector for the handler interface. While this could be a standard interface for cell handler equipment (I really don’t know if it is), this connector has become very much obsolete and difficult to obtain even from most of the big-name component distributors.
The last thing to use the Centronics 36-pin in any great capacity was the humble IBM-compatible parallel port printer. As a result, I hopped down to my local thrift shop to grab one … for its connector.
It was not an easy job to open up the moulded plug assembly without damaging the connector. Once it was freed, the next step was to desolder all of the wire remnants as the pin-out of the parallel port is significantly different from that of the handler interface.
From there, in order to check all of the necessary signals, I had to break out the important signals into header pins to plug into a breadboard. Red leads were believed to be positive power, black leads for negative power (using thicker wire for both). White leads were used for bin outputs with blue leads used for inputs/status signals. Note that this was soon altered as I understood that the connector frame ground is important and I had also misplaced one blue wire (one position to the right of shot) and corrected this. This was a relatively time-consuming process - but I was willing to do it. I guess that's why I'm chosen to do RoadTests .
Handler Interface Signals
I spent some time observing the handler interface under a number of different conditions using my Rohde Schwarz RTM3004 and my Keysight multimeter I determined that EXTDCV1/2 are sources for the high-level output for the logic output pins whereas COM1/2 are the corresponding sources for the low-level output Due to not being too worried about accuracy and out of convenience I had tested the interface with EXTDCV1/2 jumpered to the 5V line and jumpered COM1/2 to the frame ground thus turning everything into a 5V logic level interface
For the most part, the manual is mostly correct, although I’ve made things a little more explicit. For example, EXT_TRIG was determined to be a falling edge trigger. The /KEYLOCK input was found to be a toggle type input, seemingly triggered on the rising edge. The /OUT line showed the opposite behaviour to my expectation – being low to indicate the result is in a bin. Likewise, it was found that the EXT_TRIG input had an internal pull-up.
Unfortunately, I haven’t pushed the limits on any of the signals – so I don’t know how short a trigger pulse could be, how “low” it has to go to be sensed, how much current the outputs can drive safely, or what the exact setup/hold times of the signals might be.
At least, with the set-up, we can replicate a check to verify that some of the signals behave as described in the manual.
In the above graphic, C1 represents EXT_TRIG, C2 represents /EOM, C3 represents /INDEX and C4 represents one of the bin output lines that change. On the whole, this is what is expected.
External Trigger BNC Port
Also worthy of mention is the BNC port marked “TRIGGER” on the rear of the device. The port is not well documented within the manual either, with only a short mention of it on the labelled device diagram within the manual.
The BNC port on the rear appears to be connected to the EXT_TRIG of the handler interface, operating in much the same way. I measured about 4V on the port and when the centre pin was shorted to the chassis earth, the BA6010 triggered a reading on the falling edge of the signal when the trigger mode is set to EXT. I suspect the earth of the BNC port is isolated from the chassis earth allowing for an external 5V signal to be used, but if the external device is also referenced to Earth, it will probably see the 4V from the internal pull-up to the BA6010’s internal power supply.
Because the handler interface is intimately connected with the binning feature, I chose to cover this feature in this chapter rather than in Chapter 3. The binning feature allows for the analyser to categorise a given object based on its readings. Binning is available for both primary measurements (COMP_A) and secondary measurements (COMP_B) in both absolute modes and relative modes. In the absolute mode, nine bins can be configured along with their upper and lower limits for both A and B measurements. In the relative mode, the nominal values are used for comparison.
While it is possible to set the bins on the screen through the BIN SETUP menu, even with the keypad and cursor keys, it can get tedious quickly. As a result, it is more convenient to calculate the bins ahead of time and use a script (such as the pyvisa script in the appendix) to remotely set the bin values on the instrument. In case several different bin values are needed, it is possible to load one set onto the instrument and then save the instrument setting either into internal memory or to an external USB flash drive for later recall, repeating for other bin sets as necessary.
By default, if COMP_A and COMP_B is on, then a tested item is only a member of a given bin if both measured A and B values fall within the ranges. As I’ve programmed ranges which are not expected to be coincident, you can set to just use COMP_A or COMP_B to bin only on resistance or only on voltage.
The binning process is of value in manufacturing quality control processes, where use with the handler interface with external trigger makes sense. A robot (or perhaps a worker) might place the battery into the holder which closes a switch that triggers the unit to test the cell and report the result. This could be used to actuate a number of diverters in a chute to sort the battery into a physical container representing the bin value (e.g. rejected cells, marginal cells, good cells, best cells).
Experiment: Fresh Alkaline Battery Binning
A selection of Varta Longlife AA Alkaline cells were put through the bin data as set above, using COMP_A only. This allowed the cells to be sorted into bins based on the measured internal resistance.
Further to this, the BA6010 also illuminates its bi-colour Pass/Fail LED indicator to reflect whether the result is within any one of the nine configurable bins (Pass, Green) or whether it is out of all bins (Fail, Red).
The internal beeper can be configured to sound if the item passes or if the item fails.
With the use of the digital channel inputs on the Rohde & Schwarz RTM3004, it is possible to understand how the handler interface bin outputs operate on my Alkaline binning example comparing just “A” readings. I have connected D0-D9 to /BIN1-/OUT signals, with D10-D16 covering /PHI–/SLO. In the above example, we can see that a trigger is input (C1 – EXT_TRIG), which causes the unit to perform a measurement (C2 – /EOM). During the measurement, the A/D converter is used a number of times (C3 – /INDEX) due to a number of range changes and the measurement of both voltage and current. Finally, once the measurement is completed, EOM goes low and the bin outputs are updated to reflect that the primary measurement value is low (D11 – /PLO).
In this second example, the binning process is successful, sorting the cell into Bin 5 (D4 - /BIN5 goes low). The /OUT (D9) line also goes low to indicate the cell is within one of the nine bins, whereas the /PHI (D10) signal goes high to indicate that the measurement is not out of range high anymore. I suspect the /PIN line did not change because this may only be used in the percentage comparison rather than absolute binning mode.
The handler interface uses the rather “obsolete” Centronics-style 36-pin connector, which is difficult to obtain from most component suppliers. The documentation provided is also lacking many key details which are necessary to safely use the port with other equipment. This is not helped by some inconsistencies in naming of signals and ambiguous language. Likewise, the external trigger BNC port is also not well documented. Despite contacting B&K Precision Technical Support, only a limited amount of information was provided and it proved easier to just discover some of the relevant information through testing.
I was able to develop my own adapter through salvaging a connector from an old parallel-port printer cable. With this, I was able to verify the pin-out which more explicitly details the behaviour of the handler pins. There were some minor inconsistencies with the description provided by the manual, however, it was possible (in the end) to work successfully with the handler interface. Unfortunately, there still remains some details with timing and absolute voltage levels which I did not determine, which would be good to see in the documentation. Given the 25-unique-signals available, it would probably have been a better choice to use a DB-25 connector which still remain somewhat more widely available.
The binning feature allows for the analyser to categorise a given battery based on its readings. Binning is available for both primary measurements (COMP_A) and secondary measurements (COMP_B) in both absolute modes and relative modes. The binning process is of value in manufacturing quality control processes, where use with the handler interface with external trigger would allow for automated testing and sorting of batteries. A trial of the binning feature and handler interface output was successfully undertaken with some fresh AA alkaline batteries, allowing us to examine the behaviour of the bin output lines.
Appendix: pyvisa Scripts
Please note, I have supplied my pyvisa code for reference, however you may not be able to run it because it uses absolute instrument references including serial numbers, hard-coded file paths, it may require the availability of other instruments, it may be written for Python 2 and you’re trying to run it on Python 3 (or vice versa), the code may rely on Windows-only libraries. No liability is taken for this code – use it at your own risk.
Setting the Bins Remotely
# Setting the Bins of the B&K Precision BA6010
# Alkaline Battery Testing Example
# Gough Lui (goughlui.com) - September 2018
resource_manager = visa.ResourceManager()
ins_ba6010 = resource_manager.open_resource('USB0::0x0471::0x6010::520L17113::INSTR')
# Roll Call
print 'Available:' + '\n' + ins_ba6010.query('*IDN?')
# Set Up BA6010 Bins
print 'Setting Up Bins - BA6010'
# Set Instrument Settings
# Set Bin Mode (Absolute)
# Turn On/Off Comparison of Measurements
# Set Bin Normal Values (for % function)
# Set Bin Limits for A (for Absolute function)
# Set Bin Limits for B (for Absolute function)
# Change to Bin Display
# Announce Completion
print 'Script Completed!'
This blog is part of a series of posts for the B&K Precision BA6010 Battery Analyser RoadTest, where you will find all the links to the other parts of the review.