Parker ACR Series, Programmer'S Manual

Page: 137 / 176

Parker Hannifin
Flags for Extended Digital I/O
Each possible node will have two blocks of flag parameters, each 16
parameters in length, to accommodate the possible 512 bits each of
extended digital inputs and outputs. Flag parameter numbers are
shown the table below.
32 bit block type Starting parameter Ending
parameter
Node 0 digital inputs 4456 4471
Node 0 digital outputs 4472 4487
Node 1 digital inputs 4488 4503
Node 1 digital outputs 4504 4519
Node 2 digital inputs 4520 4535
Node 2 digital outputs 4536 4551
Node 3 digital inputs 4552 4567
Node 3 digital outputs 4568 4583
For each node, the lowest bit number for extended digital inputs
block of that node will correspond the lowest numbered digital input
on that node on the network. Numbering will proceed upward for all
the digital inputs on that numbered node. The same process occurs
for the Digital Outputs. This continues until the actual number of
digital inputs and outputs on the network or maximum number (512)
of digital I/O is reached. For example, the first digital input on node
0 is bit 11520, and the first digital input on node 2 is bit 13568.
Each node will have an information parameter block, described
later in this text. This block will contain, among other things, the
number of bytes of digital inputs and outputs. Digital I/O are
assigned in blocks of eight, so the number of bits assigned to each
node is a multiple of eight. For example, suppose node 2 has 12
digital inputs. Node 2’s inputs would be bits 13568-13579, even
though the node status parameter indicates that it has two bytes of
inputs. The same numbering rules apply to digital outputs.
Analog Inputs and Outputs
Analog inputs and outputs are implemented by ADCs and DACs
respectively, and unlike digital I/O, the analog values represent
something with units and a range. For example, a DAC might assert
–5V to 5V, or 0-20 mA, or some range of pressure, force, or speed.
The ADCs and DACs also have variable binary resolution (10, 12, 14
or 16 bits). All CANopen values are left shifted to occupy the entire
16 bits as a two’s complement signed number, even if the actual
ADC or DAC is less than 16 bits. This does not increase the analog
resolution. In addition, the sign of the resulting 16-bit number is the
same as the sign of the physical quantity it represents instead of
being offset. A value of 32767 represents full scale positive for the
device, and -32768 represents full scale negative for the device.
Additional Features 137