Rockwell Automation GMLC Reference Manual - Manual (Page 426)

Publication GMLC-5.2 - November 1999
DH-485 Value 389
• The node address of the motion controller’s predecessor (the device
which passes the token to the motion controller) is shown as Pred.
• The node address of the succeeding device (the one to which the
motion controller passes the token) is shown as Succ.
When there is only one other device on the DH-485 network, the address
of the predecessor is the same as that of the successor. If there are no other
masters on the DH-485 network, all three node addresses are the same.
DH-485 Value
Use the DH-485 Value block to:
•
Read a value (or multiple contiguous values) from a remote DH-485
element (or elements) and wait for the transfer to be acknowledged.
(Read Type)
• Send a value (or multiple contiguous values) from a local DH-485 or
CNET variable in the motion controller to a remote DH-485 element
(or elements), and wait for the transfer to be acknowledged. (Send
Type)
The DH-485 Value block resides on the DH-485 Palette.
For Send Type transfers, the black directional arrow points from the DH-
485 or CNET Local variable list, on the left, to the DH-485 Remote
variable list (or the Remote field group), on the right. For Read type
transfers, the arrow’s direction is reversed.
See the Using the DH-485 Option chapter for information on configuring
DH-485 operation.
Read Type
When you select DH-485 in the Configure Control Options dialog box,
the DH-485 Value block, with Read type selected, reads a value (or
multiple contiguous values) from a remote DH-485 element and
optionally waits until the requested data is received. The value or values
read are stored in local DH-485 variables in the motion controller.