Parker PDHX-E Series User Manual page 52

Attach device identifiers to the front of the command. The Go (G) command instructs all units
on the daisy chain to go, while 1G tells only unit #1 to go.
When you use a single communications port to control more than one Controller, all units in
the daisy chain receive and echo the same commands. Each device executes these
commands, unless this command is preceded with an address that differs from the units on
the daisy chain. This becomes critical if you instruct any indexer to transmit information. To
prevent all of the units on the line from responding to a command, you must precede the
command with the device address of the designated unit.
No Controller executes a device-specific command unless the unit number specified with the
command matches the Controller unit number. Device-specific commands include both
buffered and immediate commands.
You must use status-request commands in an orderly fashion. Commands should only be
issued when the host is ready to read the response. You should not send new commands
until you receive a response from the previous status-request command. In particular, you
should not issue an immediate-status command until the host receives a buffered command
status response. If this is not followed, the command responses will be intertwined,
rendering the data useless.
If you enable the Interactive mode (EX1), the Controller that is currently echoing will respond
with a prompt (>). This prevents all the Controllers from sending out > in a daisy chain.
Typically, you should disable the Interactive mode when you use a host computer with the
Controller. The default for the EX command is enabled (EX1).
Figure 6-2 shows a multiple-drive configuration (daisy-chain) of RS-232C ports from one
controlling terminal or computer.
Terminal
Gnd
Figure 6-2. RS-232C Daisy Chain Configuration
Example
Three Controllers are connected to an RS-232C daisy chain. Send the following commands:
Command Description
MN Sets unit to Preset mode for all three controllers
A5 Sets acceleration to 5 rps
V10 Sets velocity to 10 rps for all three controllers
LD3 Disables limits (if they are not connected)
1D25000 Sets axis 1 distance to 25,000 steps
2D50000 Sets axis 2 distance to 50,000 steps
3D100000 Sets axis 3 distance to 100,000 steps
G Moves all axes
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Device 1
1
Gnd
Tx
Rx
Tx
5
Rx
Device 2 Device 3
1
Gnd
Rx
Rx
Tx
5
2
for all three controllers
1
Tx
5