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Page 11
Revised 7/95 DFS-1 Manual
POWERTEC Ind. Corp.©
The programmable inputs (TB2-A4 through
TB2-A10) may be programmed for jog, thread, or
other preset speeds. The inputs may also be used to
change torque levels, trim values, or ramp rates. Any
value which can be affected by a parameter can be
changed by a digital input.
DIGITAL OUTPUTS:
Digital outputs are located on TB2:B. The four
outputs are normally open relay contacts. The
contacts are rated at 120VAC at 1 amp, resistive.
The default setup assigns the outputs as follows:
Digital Out #1 Run
Digital Out #2 No Fault
Digital Out #3 At Speed
Digital Out #4 Reverse
These assignments may be changed by parameters.
All of the digital outputs are programmable and
may be configured as Normally Open or Normally
Closed. If more than one contact is required for a
certain function, an external relay may be used, or
more than one output may be programmed for the
same function.
COMMUNICATIONS:
The standard communications for the DFS-1 is
the EIA standard RS-485 communications format
over a single twisted pair cable into TB3:A terminals
1 and 2. Terminal 3 is for the shield. DO NOT
CONNECT TERMINAL 3 TO GROUND! Maxi-
mum allowable distance for twisted pair operation is
4000 meters (about 12,000 feet). Maximum nodes
without repeaters is 32. Maximum communications
rate is 38.4 kilobaud. The last unit on the comm line
should have a jumper at JP2 on the rightmost 2 pins.
All other units should have the jumper on the
leftmost two pins.
There is an RS-485 local programming input at
TB3:B for an optional keypad display unit.
RS485 Communications Connections:
Most host or converter devices (including the
RS232/485 converter made by POWERTEC) include
1.2 Kohm pull up resistors which insure rx-tx- is
pulled down to ground and rx/tx+ is pulled up to +5V
when the line is inactive (tristated). This ensures the
high impedance (floating) line does not change state
due to noise when the line is not being driven. No
matter how many units are connected in the network,
only one such set of pull ups should be installed.
NOTE: The Allen Bradley RS485 connections
on their coprocessor module for the Series 5 PLCs do
not provide these pull ups and must be installed or
noise will prevent proper communications.
tx/rx+
1.2K ohm
tx/rx-
TB1A-8
TB3A-1
1.2K ohm
TB3A-2
TB3A-4