26 Installing the DCM and Starting the Network

26 Installing the DCM and Starting the Network
26
Installing the DCM and Starting the Network
Installing the DCM and Starting the Network
Install the DCM
If you’re using a DCM as the network interface in a PLC master station, make a note
of the slot location. (This will be used in the RLL communications program. See
Appendix A for details). If you’re connecting the DCM to a host computer or operator
interface master you can install the DCM in any slot of the slave station.
NOTE: The DCM can not be mounted in a base that does not contain a DL405 CPU.
Also, the DCM requires 500 mA of +5V base power. Make sure you will not exceed
the available base power budget by installing the DCM. See the DL405 User Manual
for complete details on power budget calculations.
WARNING: To minimize the risk of electrical shock, personal injury, or
equipment damage, always disconnect the system power before installing or
removing any system component.
1. Notice the I/O module has a plastic tab
at the bottom and a screw at the top.
2. With the module tilted slightly forward,
hook the plastic tab on the module into
the notch on the base.
3. Then gently push the top of the module
back toward the base until it is firmly
installed into the base.
4. Now tighten the screw at the top of the
module to secure the module to the
base.
Connect the
Cables
Make sure you have all the cables connected and that all the network devices have
the same communication parameters (baud rate, parity, etc).
If you’re using
DirectNET...
The PLC master station must contain an RLL communications program . (See
Appendix A for details on the RX and WX instructions). The master station CPU must
be in Run mode in order to execute the communications program. The slave station
CPUs do not absolutely have to be in Run mode because the DCM will still transfer
the data. Whether you put the slave stations in Run mode depends on your
application requirements.
RUN
PWR
BATT
TERM
RUN
I/O
STOP
CPU
COM
27
27
Installing the DCM and Starting the Network
If you’re using an
Connect the cables and follow the procedures outlined in the documentation that
Operator Interface came with your host computer software or operator interface. You’ll have to execute
or Host Computer... your host or operator interface program before the communications can begin. For
example, if you’re using DirectSOFT, you can just specify the station address and
start working!
If you’re using
Modbus...
Follow the procedures outlined in your Modbus Host software package to start the
communications. The following table provides the types of operations allowed and a
cross reference for the DL405 memory types.
DL405
Memory Type
Range
(Octal)
Operations
Allowed
Modbus
Starting
Reference (Hex)
Modbus
Function
V memory
0000–7777
Read
Write
0000h
0000h
03 and 04
06
X (input)
000–477
Read
0800h
02
Y (output)
000–477
Read
Write
Write Multiple
0800h
01
05
15
C (control relay)
000–737
Read
Write
Write Multiple
0C00h
01
05
15
Timer (contact)
000–177
Read
Write
Write Multiple
1800h
01
05
15
Counter (contact)
000–177
Read
Write
Write Multiple
1900h
01
05
15
Stage (status bit)
000–577
Read
Write
Write Multiple
1400h
01
05
15
SP (special relay)
000–137
320–617
Read
Read
0D00h
0DD0h
02
02
NOTE:
1. You cannot access V-memory addresses above V7777 (octal).
2. With Function 15, Write Multiple coils, you must write in 8 bit increments.
This function is not supported with the number of coils less than 8.
3. Timer and counter current values are stored in V-memory areas
V000–V177 and V1000–V1177 respectively. These values are stored in
BCD format unlike the remainder of V memory which is stored in binary.
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