Section 6. Communicating With The Positioner - Parker PDHX-E Series User Manual

Section 6. COMMUNICATING WITH THE POSITIONER

Chapter Objectives
The information contained in this chapter will enable you to set up communications with the
positioner using an RS232C serial link. If more than one positioner is present in the system,
details are provided on the connection of multiple positioners using the RS-232 Daisy Chain.
Command Interface
The interface is a three wire implementation (Tx, Rx, Ground) of RS232C. The Tx and Rx
lines requires a minimum voltage swing of ±3 volts.
Hardware handshaking is not supported in any form. The computer or terminal sending
characters to the positioner should have its handshaking disabled by either hardware or
software.
Communication Parameters
The positioner communications protocol is fixed and as follows:-
9600 baud, 8 data bits, no parity, 1 start bit, 1 stop bit
Device address: 1-32
Echo function: all characters received are immediately re-transmitted. This function can be
enabled using the SSA0 command or disabled using the SSA1 command.
Once entered, a parameter will be remembered until power down. It is not necessary to keep
re-stating the same parameter value.
When you power up the positioner, all parameters are assigned default values which the 1DR
command will show you. You can change any of these and then make them the new default
value by typing the SV (Save command).
(see also commands RFS, RIFS).
XON, XOFF software handshaking is supported.
Installing the RS232C
RS232C connections from the controller to the positioner are as shown in Figure 6-2. Note
that the Tx and Rx lines are cross-connected so that transmit output is connected to receive
input.
Address Selection
A unique address must be assigned to each positioner in the chain. Normally positioner 1
will be the first in the serial communications link. The positioner's address is assigned by
configuring the DIL switch on top of the drive in a binary pattern as shown in Table 6-1.
The DIL switch can be accessed through the ventilation slots in the top of the drive using a
small screwdriver or similar tool. Make sure that the AC power is disconnected before
attempting to change the switch settings. SW1 is nearest to the front of the drive.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com