Control Techniques Epsilon EP-P Reference Manual Download Page 36

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Epsilon EP-P Drive Reference Manual

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www.controltechniques.com

Revision: A4

NOTE

No motion should be commanded while the brake is engaged.

Brake Release

The Brake.Release destination function will release the brake under all conditions. When this function is active, the Brake output will be on
(that is, release brake). This function overrides all other brake control, thus allowing the brake to be released while a fault is active or the power
stage is disabled.

Brake Activate

The Brake.Activate destination function, when active, will engage the brake unless overridden by the Brake Release function. This function lets
you externally engage the brake while allowing the drive to also control the brake during fault and disabled conditions.

Brake Disengaged

The Brake.Disengaged source function is used to control the motor holding brake. If the Brake function is off, the brake is mechanically
engaged. When the brake is engaged, the diagnostic display on the front of the drive will display a “b”.
The drive outputs are limited to 150 mA capacity, therefore, a suppressed relay is required to control motor coil. Control Techniques offers a
relay, model # BRM-1.

2.9

How Data Capture Works

Data Capture is a mechanism to capture data and display that data graphically. The capture mechanism is part of the drive and captures drive
data as fast as 100 usec. Data is captured in a circular 8 K byte buffer. The format is fixed at 4 channels of 32 bit words for a total of 512 time
samples. The circular buffer is continuously loaded until the trigger condition (or command abort) stops loading data. The capture mechanism
follows three buffer states - Filling Buffer, Waiting for trigger, and Triggered.
At the start of the Run command, the buffer starts to fill (filling the whole buffer). The buffer must be completely filled before the trigger is
armed. Once the buffer is filled, the buffer state will display - Waiting for Trigger. When the trigger is detected, the data capture is stopped
(triggered). The sampling rate is based on the trajectory update rate. The sample rate can be adjusted in multiples of the trajectory update rate.
PowerTools displays this in the form of seconds. At the update sampling, a new set of data is overwritten into the circular buffer and the trigger
is checked.
The Data Capture update rate for the Epsilon EP-P drive is 100 usec. The drive captures data at the user selectable trajectory update rate of
800, 1200 or 1600 usec for Drive Inputs, Drive Outputs and Custom Variables. This means if the Data Capture rate is faster then the Epsilon
EP-P drive trajectory update rate the user will be sampling data faster than it is changing. All other parameters in the Select list box are
captured at 100 usec except Bus Voltage and Following Error which are 400 usec.
The trigger detection checks the data level. It does not specially look for an edge. Once the buffer is filled the trigger is armed and the check for
trigger level is started. Since the drive is looking back in the buffer at data captured during the fill, the trigger condition may already exist. If that
is so, the drive immediately transitions to the trigger state. If not, the drive continues the data capture cycle of sample and trigger check until
the trigger is detected at the edge of the data transition. When the Trigger Falling Edge check box is selected the trigger is detected when the
data transitions below the trigger level.
When sampling digital inputs and outputs, the data captured is binary bit mapped. The state of all the digital signals in the group selected are
encoded into one 32 bit word. When this is graphed it is displayed as an analog signal. To trigger on this bit map data, the trigger mechanism
is changed to a mask. The user can select one of the bits to trigger on.
The captured data is uploaded when the

UploadPlot

button is pressed. Once uploaded, PowerTools plots the data in graph window. Data is

also saved in a data file named, PtProGraphData.csv. This data file can be exported to a spread sheet for data manipulation and graphing.

2.9.1

Navigating the Graph Window

The Graph window display can be altered, double-click anywhere in the Graph Window except on the graph area itself. The Customization
dialog box opens and contains tabbed graph options. Many of the graphs attributes, such as colors, line format, etc. can be changed in this
box. The graph can also be exported to a file.
Holding the shift key down while moving the mouse allows the user to zoom in on the graph area. Double-click on the graph area and the
Graph Coordinate window opens and gives the x/y coordinate of where the mouse point was when double-clicked.
The Graph window overlaps the data into a Y axis if the next channel has the same units. If the units change for the next channel, a new graph
on the Y axis is added to the plot. If None is selected for a channel the drive data capture samples zero for that channel an PowerTools ignores
plotting that channel. The Reserved channel selection is for internal use only and also captures zero. The title of the graph matches the
application’s name defined on the Setup view.
Graph settings are downloaded to the drive when the

Run

button is pressed. Only changed values are sent. The graph settings are the same

as any application variable. When a variable is changed in a PowerTools view the

Update to RAM

button is available, indicating the

application and drive are out of sync, (

Update to RAM

remains unavailable if the user changes a variable that requires a reboot. The user then

requires a full download). When the

Run

button is pressed, it does a limited Update to RAM by downloading the changed graph settings to

RAM.