Parker PAC, Руководство по установке, Страница: 121 / 197

Function
The PACIO Counter/Enc Module has two identical channels. Each channel has terminals for one encoder,
four digital inputs, one digital output, and one analog output.
The documentation organizes the variables into structured groups:

Module Control/Module Status for controlling and monitoring the entire module.

Options/Control/Status/Errors for controlling and monitoring the Counter 1 & 2 resp. 2.

Set Values/Current Values for determining the Counter values of Counter 1 & 2 resp. 2.

Digital Outputs/Digital Inputs/Input Change Time Stamp/Output Delay for monitoring the state
of the digital IOs of Counter 1 & 2 resp. 2.
Principle of Control and Status
If a control bit is set (=TRUE), the module will operate the corresponding function due to the rising edge of
the bit. The Module indicates the execution of the function by setting the corresponding status bit (=TRUE).
When the control bit is reset (=FALSE), the Module will also reset the status bit (=FALSE).
NOTE: In the following example, the functions of the counter Module are described for Counter 1.
Counter 2 has corresponding functions.
Frame- or DC-Synchronous Mode
Dependent on whether Distributed Clocks (DC) are used or not, the Module adjusts itself independently on
the suitable mode of operation. The Module is pre-set to Frame synchronous mode. With the receipt of the
first DC telegram, the Module is changed over to DC-synchronous mode and maintains this mode of
operation until the module is powered down.
Frame-Synchronous Mode
The EtherCAT master sends EtherCAT frames with the output data for the Module. With the arrival of such
frame the output data are taken over and processed by the Module. The Module places its input data into
the EtherCAT frame, so that the master can receive it.
DC-Synchronous Mode
If the Module is adjusted to DC-synchronous mode, it produces interrupts according to the rules of the DC.
The EtherCAT master also sends EtherCAT frames with the output data for the Module. With the arrival of
these frames, the output data of the Module are taken over and processed only if a DC interrupt has
occurred. With the DC interrupt, the Module places its input data into a buffer, from which they are
transported with the next EtherCAT Frame to the master.
With this method, time-synchronous functions for digital inputs and digital outputs for several Modules in
one EtherCAT network are possible.