Parker Compumotor ZETA6104, Руководство по установке

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8
z
ZETA6104 Installation Guide
Serial Communication
Rx
Tx
GND
SHLD
COM 1
COM 2 +5V
GND
Rx
Tx
SHLD Rx+
RxÐ
Tx+
TxÐ
GND
Rx
Tx
GND
SHLD
RS-232C Connections
25-Pin COM Port: 9-Pin COM Port:
Serial Port Connection
Tx
Rx
GND
RS-232C Daisy-Chain Connections*
Unit 0
Rx
Tx
GND
SHLD
Unit 1
Rx
Tx
GND
SHLD
Unit 2
Tx
Rx
GND
Daisy Chain to a Computer or Terminal
Rx
Tx
GND
SHLD
Unit 0
Rx
Tx
GND
SHLD
Unit 1
Rx
Tx
GND
SHLD
Unit 2
Stand-Alone Daisy Chain
Be sure to set unique devices addresses for each unit.
To set the address, use the DIP switch (see page 4),
or use the
ADDR
command (see 6000 Series ProgrammerÕs Guide ).
*
NOTE : Maximum RS-232C cable length is 50 feet (15.25 meters)
Rx
Tx
GND
Pin 2 (Rx)
Pin 3 (Tx)
Pin 5 (GND)
Rx
Tx
GND
Pin 2 (Tx)
Pin 3 (Rx)
Pin 7 (GND)
Rx+
RxÐ
Tx+
TxÐ
GND
COM 2 +5V
GND
Rx
Tx
SHLD
Rx+
RxÐ
Tx+
TxÐ
GND
COM 2 +5V
GND
Rx
Tx
SHLD
Rx+
RxÐ
Tx+
TxÐ
GND
COM 2 +5V
GND
Rx
Tx
SHLD
Rx+
RxÐ
Tx+
TxÐ
GND
COM 2 +5V
GND
Rx
Tx
SHLD
Rc
Vcc
Rd
Vb Rb
Balanced Cable.
Ra
Step 1 Calculate the equivalent resistance (Req)* of Rc / / Rb:
Rc / / Rb = 120
W
/ / 120
W
= 60
W
Step 2 Calculate the pull-up and pull-down resistor values knowing that
the FAILSAFE bias is 200mV and Vcc = 5V:
Vb = Vcc (Req / (Ra + Req + Rd))
solving for R' (defined as Ra + Rd)
R' = ((Req) Vcc / Vb) - Req
R' = ((60
W
) 5V / 0.2V) - 60
W
= 1440
W
Since Ra and Rd are equal, Ra = Rd = 1440
W
/ 2 = 720
W
Step 3 Recalculate the equivalent resistance of RC / / (Ra + Rd):
Rc / / (Ra + Rd) = 120
W
/ / (720
W
+ 720
W
) = 110.77
W
Since the equivalent resistance is close (within 10%) to the characteristic
impedance of the cable (Zo), no further adjustment of resistor values is
required.
Example
Assumptions: The cable's characteristic impedance (Zo) = 120
W
.
Rc and Rb are equal and are selected to match Zo
(Rc = Rb = Zo = 120
W
).
For further information,
consult a communications
interface reference.
*
Actual calculation
for equivalent resistance
(e.g., R1 / / R2):
R1 R2
(R1 + R2)
RS-485 Connections (4-wire interface, plus ground)
Master
Unit
Tx+
RS-485 Configuration
Before you can use RS-485
communication, you must re-
configure the COM 2 port by
setting internal jumpers JU1-JU6
to position 1. 4-wire is default
(to use 2-wire, set JU7 to
position 1).
Refer to page 5 for instructions.
TxÐ
Rx+
RxÐ
120
W
120
W
Shield
Unit #1
Unit #2
Unit #3
Unit #31
DIP switch selects internal resistor values (ON selects the resistor).
Use these resistors only for the last unit (or for a single unit).
If your application requires terminating resistors other than 120
W
,
and/or bias resistors other than 681
W
, then make sure the internal
DIP switches are set to OFF and connect your own external resistors.
To calculate resistor values:
5VDC
120
W
681
W
Calculating Resistor Values
681
W
12
34
O N
120
W
+5VDC
NOTE : Maximum RS-485 cable length is 4000 feet (1220 meters)
Ground
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