20 Setting the DCM Switches

20 Setting the DCM Switches
20
Setting the DCM Switches
Setting the DCM Switches
The device(s) connected to the DCM will help you determine the appropriate switch
settings.
Host Computer or
Operator Interface
Connection
If you’re using a host computer or operator interface as the master station you must
set the DCM to match the master station parameters. Check the documentation that
came with your computer or operator interface to determine the available
communication parameters.
You’ll need to know the following things.
D
Baud rate
D
Parity settings
D
Protocol
NOTE: Some operator interfaces should be connected to the DL405 programming
port (top port) and cannot be used with the DCM. Make sure your operator interface
uses one of the following protocols.
D
DirectNET (DL430, DL440, D4–DCM)
D
Hostlink (TIt or Simaticr TI425, -430, -435, U-01DM)
D
Modbus RTU
You may still be able to use an operator interface designed for the programming port
with the DCM if:
D
Your DCM has firmware release 1.4 or higher and your CPU has
firmware releases 2.1 or higher.
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21
Setting the DCM Switches
DirectNET Interface If you’re using the DCM as a DirectNET interface, you’ll need to know whether the
DCM is being used in a master station, slave station, or peer station. Once you’ve
Connection
determined how the DCM will be used, proceed with the dipswitch settings.
22
Setting the DCM Switches
DCM
Switch Settings
There are two banks of switches located on the rear of the DCM that are used to set
the communications and protocol parameters. The following diagram shows the
locations and setting options.
OFF ON
Switch Positions
Time*
6
7
8
0 OFF OFF OFF
2 ON OFF OFF
5 OFF ON OFF
10 ON ON OFF
20 OFF OFF ON
50 ON OFF ON
100 OFF ON ON
500 ON ON ON
1
2
3
4
5
6
7
8
NO Parity
Set to OFF
Delay Time
*Delay time in milliseconds
Baud Rate
ODD Parity
Self Test
SW4
1
2
3
4
COM Timeout Enable
Hexadecimal Mode
Network
Protocol
Switch Positions
Baud
1
2
3
300 ON OFF OFF
600 OFF ON OFF
1200 ON ON OFF
2400 OFF OFF ON
4800 ON OFF ON
9600 OFF ON ON
19200 ON ON ON
38400 OFF OFF OFF
Switch Positions
Protocol
1
DirectNET Slave
OFF
DirectNET Master
OFF
DirectNET Peer
ON
Modbus RTU
ON
2
OFF
ON
OFF
ON
COM Timeout Disable
ASCII Mode
SW5
Baud Rate: Positions 1 – 3 on SW4 are used to set the baud rate for the DCM. There
are eight baud rate selections available ranging from 300bps to 38.4Kbps. All
stations must have the same baud rate before the communications will operate
correctly. Usually, you will use the highest baud rate possible unless noise problems
appear. If noise problems appear, try reducing the baud rates.
Parity: Position 4 on SW4 selects between the two parity options, odd or none. If
you’re using all DL405 equipment, you can use odd parity. Odd parity uses eleven
bits total (1 start bit, 8 data bits, 1 stop bit, and 1 parity bit).
Some devices require no parity, which uses only 10 bits (1 start bit, 8 data bits, and 1
stop bit).
Self-Test: Position 5 on SW4 selects the factory self-test and must always be
switched off. If the self-test is on, the module will not operate correctly.
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Setting the DCM Switches
Response Delay Time: Positions 6–8 on SW4 set the response delay time. This
sets how long the DCM will wait before it responds to each component of a
DirectNET or Modbus communication request. If you’re using all DL405
equipment, a response delay is not required and you will set the time to 0.
The DCM may respond too quickly for some devices, such as telephone or radio
modems. If you encounter this problem just choose a delay from 0 to 500 mS. Your
device manual should suggest the proper settings.
Protocol Selection: Positions 1 and 2 on SW5 select the DCM protocol and the
master or slave settings. The DCM can use two protocols, DirectNET and Modbus
RTU protocol.
Computer or Operator Interface: If you’re using the DCM to connect a computer or
operator interface, check your documentation to see which protocol is being used.
Since the DCM is always a slave station when it’s connected to a computer or
operator interface, you should select DirectNET slave or Modbus RTU slave.
DirectNET Master / Slave: In a DirectNET master / slave network, one DCM should
be set as a master and the rest should be set as slaves.
DirectNET Peer as Master: This is a variation of the master / slave protocol and
should be selected when you only have two stations that can each initiate requests.
Each station should have a DCM as the network interface.
Modbus Slave: The DCM can also be a Modbus slave (in the RTU or HEX mode).
The DCM cannot be a Modbus master station. If you’re going to use Modbus,
make sure your software package supports the DL405 products. The following
drivers should work correctly.
DL405 (DL430, DL440, D4–DCM)
Series 405 (TI or Simatic TI425, -430, -435, U-01DM)
Communication Timeout: Position 3 on SW5 selects the communication timeout.
Don’t disable the timeout for normal use. Communication Timeout Disable is
normally used only if you’re developing your own DirectNET programs. By disabling
the timeout, you can send one DirectNET component without any communication
timeout problems. If you have this timeout disabled and a communication error does
occur, you must restart communications by sending a retry or an End of
Transmission (EOT) command. If you want to know more, see the DirectNET
manual for details.
ASCII / HEX Mode: Position 4 on SW5 selects between ASCII and HEX modes of
data representation. If you want the fastest communication possible, use HEX
mode. The difference is in the way the data is represented. The same data is twice as
long in ASCII format, so if there’s more data, it takes longer to transfer. If you have a
device on the network that requires ASCII mode, then set the switch for ASCII mode,
otherwise, use HEX mode.
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Setting the DCM Switches
Online / Offline
Switch
In the Offline position, this switch logically
disconnects the DCM from the network (just
as if you pulled the cable from the connector).
Once this switch is moved to the Offline
position, the DCM will not communicate with
the network. If you move the switch to the
Online position, the DCM will communicate
with the network, but not until the master
sends another request for communication.
This does not operate like the reset switch on
many personal computers.
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Setting the DCM Switches
Address Selection
Switch
The DCM station address is set by the two
rotary switches located on the front of the unit.
Addresses are in hexadecimal format with
valid addresses from 0 (only used for the
master station) to hexadecimal 5A. The
addresses do not have to be sequential, but
each station must have a unique address.
The top rotary switch is used to set the most
significant digit of the HEX address. The
bottom switch is used to set the least significant
digit of the HEX address. For example, to set a
DCM address of HEX 10 (decimal 16), set the
top rotary switch to 1 and the bottom rotary
switch to 0. If you’re using the DCM as a
master, make sure you select address 0.
NOTE: The DCM address switch settings are
only read at power up. If you’ve want to change
the address and the DCM is already up and
running, you’ll have to cycle the system power
to make the change.
Even though the DCM address is set in
hexadecimal, it’s a good idea to remember the
decimal equivalent. This is because the
communications program and the DirectSOFT
package use the decimal equivalent of the HEX
address. It’s easy to convert from hex to
decimal.
HEX Format
0 1 2 3 4 5 6 7 8 9
A B C
D
E
F
10 11 12 13 14 15
HEX 3C
3 x 16 = 48
+
C = 12
= 60 decimal
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