Reference Manual

PMAC 2 Software Reference
PMAC I-Variable Specification 157
I1001 MACRO Ring Check Period
Range
0 .. 255
Units
servo cycles
Default
0
Remarks
I1001 determines the period for PMAC to evaluate whether there has been a MACRO ring
failure. If I1001 is greater than 0, PMAC must receive a sufficient number of “sync node”
packets (the packet is specified by I996), and not detect too many ring communications
errors, in I1001 servo cycles. If either of these conditions is not met, PMAC will consider
there to be a ring fault, and it will disable all of its slave MACRO nodes.
If I1001 is 0 at power-up/reset, PMAC does not perform these checks, even if the MACRO
ring is active. To start performing these checks, set I1001 to a value greater than 0, issue a
SAVE command, then reset the card with a $$$ command.
If I1001 is greater than 0 at power-up/reset, the check period can be changed immediately
by changing the value of I1001; there is no need to SAVE the new value and reset the card
to get the new value to take effect.
In PMAC firmware versions V1.16D and older, PMAC performs these checks during its
background “housekeeping” cycle, executed once between each scan of each background
uncompiled PLC (all compiled background PLCs execute a scan each between each
housekeeping cycle). Each cycle, it can detect at most one sync node packet and one
communications error. In these firmware versions, the number of sync node packets
required in an I1001 check period to continue operation is fixed at 2, and the number of
communications errors in an I1001 check period that will cause disabling of operations
over the ring is fixed at 2.
In PMAC firmware versions V1.16E and newer, PMAC performs these checks during its
“real-time” interrupt (RTI) tasks, every (I8 + 1) servo cycles. Each RTI, it can detect at
most one sync node packet and one communications error. In these firmware versions the
number of sync node packets required in an I1001 check period to continue operation is set
by I1005, and the number of communications errors in an I1001 check period that will
cause disabling of operations over the ring is set by I1004.
In all firmware, it is vital that I1001 be set large enough that enough checks of the ring can
be executed in the allotted I1001 check period.
With the default servo update of 2.25 kHz (440 usec), an I1001 value of 10 sets the check
period at 4.4 msec. An I1001 value of 20 sets the check period at 8.8 msec.
See Also
I-variables I996, I1004, I1005
I1002 MACRO Node Protocol Type Control
Range
0 .. $FFFF (0 .. 65,535)
Units
none
Default
0
Remarks
I1002 controls for each MACRO node (0 – 15) whether the Type 0 or Type 1 MACRO
protocol is used on that node. I1002 is a 16-bit value; each bit 0 – 15 controls the protocol
type for the MACRO node of the same number. A value of 0 in the bit selects the Type 0
protocol for the matching MACRO node; a value of 1 in the bit selects the Type 1 protocol
for the node.