AutomationDirect D2-DCM User manual

Errata Sheet
Page 1 of 3
Product Family:DL205 / DL305
Manual Number D2-DCM
Revision and Date 2nd Edition; February 2003
Date: September 2018
This Errata Sheet contains corrections or changes
made after the publication of this manual.
Errata Sheet
Change to Table of Contents
There is a typo on the first page of the Table of Contents. “Install” is spelled “Insall” for the section named “Install the D2-DCM”.
Change to Page 2. Introduction
Add the following note to this page:
NOTE: The D3-DCM module is only supported by the D3-350 processor only.
Change to Page 7. Specifications
In the Operating Specifications table, revise the “CPU Required” entry. It should say:
D2-240 (firmware V1.8 or later), D2-250-1 and D2-260
Change to Page 11. Building the Cable
The NOTE at the bottom of the page is incorrect. Only the D2-230 and D2-240 CPUs support RS232 only. D2-250(-1) and
D2-260 CPUs support RS232/422/485 without extra hardware.
Change to Page 12. Building the Cable (continued)
Change the refererence in the first paragraph to “Belden 9855” cable to “AutomationDirect L19772-1 (Belden 8102)
or equivalent”.
Change to Page 13. Building the Cable (continued)
In the first paragraph, change the last sentence to “For example, AutomationDirect L19772-1 (Belden 8102) or equivalent has a
nominal characteristic impedance of 100 ohms”.
In the top wiring drawing (“Line-to-Line Termination for the D2-DCM”), change both “120 Ohm Resistor” callouts to “100 Ohm
Resistor”.
In the bottom wiring drawing, change the “65 Ohm Resistors” callouts to “51 Ohm Resistors”.
In the top drawing, move the termination resistor on the left connector (Master) from the 24-25 pins to the 16-17 pins.

Errata Sheet
This Errata Sheet contains corrections or changes
made after the publication of this manual.
Errata Sheet
Changes to Appendix A. Cable Diagrams
Page A-4. Point-to-Point RS422 D2–DCM as Master
In the lower left drawing there are some pin number errors for the DL405 port 1 25-pin connector. The correct pin numbers are:
19 +RTS (not 10 as shown)
18 -RTS (not 11 as shown)
11 +CTS (not 12 as shown)
23 -CTS (not 13 as shown)
In the top set of drawings, change the callout that says “DL405 CPU Bottom Port” to DL405 Port 1”
Page 2 of 3
The Change to Page 17. D2–DCM Switch Settings
Add the following note near the first bullet point, “DirectNET Slave”:
NOTE: Although it is not listed in the switch settings, K-sequence is also available whenever the D2–DCM is set for DirectNET
Slave operation.
Change to Page 18. D2–DCM Switch Settings (continued)
There is an error in the last paragraph, “Response Delay Time”. The first sentence refers to switch “SW4”. It should say “SW5”.
(SW4 is used for firmware updates.)
Change to Page 21. Install the D2–DCM and Starting the Network
Add the following note to this page:
D3-DCM cannot be mounted in the farthest slot from the CPU in a base. It requires 300 mA of +9 V base power. Make sure you
will not exceed the available base power budget by installing the D3-DCM.
See the DL305 User Manual for complete details on power budget calculations.

Errata Sheet
This Errata Sheet contains corrections or changes
made after the publication of this manual.
Errata Sheet
Change to Appendix A. Cable Diagrams (continued)
Page A-7. Revisions were made to both drawings:
Page 3 of 3
RS422
22
23
24
25
+OUT
–OUT
–IN
+IN
7 GND
10
11
12
13
14
15
16
17
22
23
24
25
+RTS
–RTS
+CTS
–CTS
+OUT
–OUT
–IN
+IN
+OUT
–OUT
–IN
+IN
7 GND
10
11
12
13
14
15
16
17
+RTS
–RTS
+CTS
–CTS
+OUT
–OUT
–IN
+IN
7 GND
10
11
12
13
14
15
16
17
+RTS
–RTS
+CTS
–CTS
+OUT
–OUT
–IN
+IN
D2–DCM Master D4–DCM D2–DCM
Termination Resistor
Master
Slaves
DL405 or
DL205 DCM
D3-422-DCU
22
23
24
25
+OUT
–OUT
–IN
+IN
7 GND
10
11
12
13
14
15
16
17
+RTS
–RTS
+CTS
–CTS
+OUT
–OUT
–IN
+IN
Termination Resistor
224SR224SR
DL205
22
23
24
25
+OUT
–OUT
–IN
+IN
DL205
D3-422-DCU
7 GND
10
11
12
13
14
15
16
17
22
23
24
25
+RTS
–RTS
+CTS
–CTS
+OUT
–OUT
–IN
+IN
+OUT
–OUT
–IN
+IN
7 GND
19
18
11
23
14
16
10
9
+RTS
–RTS
+CTS
–CTS
+OUT
–OUT
–IN
+IN
7 GND
19
18
11
23
14
16
10
9
+RTS
–RTS
+CTS
–CTS
+OUT
–OUT
–IN
+IN
7 GND
19
18
11
23
14
16
10
9
+RTS
–RTS
+CTS
–CTS
+OUT
–OUT
–IN
+IN
Termination Resistor
Termination Resistor
DL405 CPU
Port 1
RS422 224SR224SR
Master
Slaves
D2–DCM Master
DL405 CPU
DL205
Port #1
DL405 CPU
Port #1
DL405 CPU
Port #1
DL405 CPU
Port 1
DL405 CPU
Port 1
Change to Appendix A. Cable Diagrams (continued)
Page A-8. Change the call-out that says “DL240 CPU Bottom Port or DL450 Phone Jack” to:“DL450 Port 2 (RJ12)”

D2–DCM
Data Communications
Module
Manual Number D2–DCM–M

WARNING
Thank you for purchasing automation equipment from Automationdirect.com. We want your new DirectLOGIC
automation equipment to operate safely. Anyone who installs or uses this equipment should read this publication (and
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To minimize the risk of potential safety problems, you should follow all applicable local and national codes that regulate
the installation and operation of your equipment. These codes vary from area to area and usually change with time. It is
your responsibility to determine which codes should be followed, and to verify that the equipment, installation, and
operation are in compliance with the latest revision of these codes.
At a minimum, you should follow all applicable sections of the National Fire Code, National Electrical Code, and the
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Afin de réduire au minimum le risque d’éventuels problèmes de sécurité, vous devez respecter tous les codes locaux et
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1
Manual Revisions
If you contact us in reference to this manual, please remember to include the revision number.
Title: DL205 Data Communications Module
Manual Number: D2–DCM–M
Issue Date Description of Changes
Original 5/96 Original Issue
Rev. A 5/98 Downsize to spiral
Rev. A
Minor changes
2nd Edition 2/03 Upgrade with DL06 and DirectSOFT32;
added MDM–TEL information

1
Table of Contents
Introduction
Overview 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Purpose of this Manual 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supplemental Manuals 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Who Should Read this Manual 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technical Support 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conventions Used 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Key Topics for Each Chapter 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D2–DCM Hardware 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Applications 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
As a DirectNET Interface 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
As an Extra Communication Port 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
As a MODBUS) Network Interface 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Environmental Specifications 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Specifications 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Using your D2–DCM– Five Steps 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Building the Cable
Building the Communication Cable 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consideration 1: Physical Configuration 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consideration 2: Electrical Specification RS232C or RS422 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consideration 3: Cable Schematics 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consideration 4: Cable Specifications 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consideration 5: Installation Guidelines 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A Quick Test Cable 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting the Switches
Setting the D2–DCM switches 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Host Computer or Operator Interface Connection 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DirectNET Interface Connection 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D2–DCM Switch Settings 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Address Selection Switch 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Online / Offline Switch 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Insall the D2–DCM
Install the D2–DCM and Starting the Network 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Install the D2–DCM 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connect the Cables 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If you’re using DirectNET... 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If you’re using an Operator Interface or Host Computer... 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If you’re using MODBUS)... 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Verification & Troubleshooting
Verification and Troubleshooting 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Quick Steps 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Chart 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ii Table of Contents
Appendix A: Cable Diagrams
Point-to-Point RS232C D2–DCM as Master A–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Point-to-Point RS232C PC as Master A–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Point-to-Point RS422 D2–DCM as Master A–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Point-to-Point RS422 PC as Master A–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multidrop RS422 D2–DCM as Master A–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multidrop RS422 PC as Master A–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DV–1000 Cable A–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix B: RLL Communications Programs
Why do you need networking instructions in your RLL? B–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Master Initiates Requests B–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Why Ladder Logic? B–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Identifying the master and slave locations & addresses B–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifying the amount of data to transfer B–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Designating the master station memory area B–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Identifying the slave station memory area to read or write B–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Controlling the communications B–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communications Special Relays B–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multiple Read and Write Interlocks B–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix C: Using the D2–DCM with MODBUS
Introduction C–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How Does the D2–DCM work with MODBUS? C–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODBUS Function Codes Supported C–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODBUS Data Types Supported C–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Determining the MODBUS Address C–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If the Host Software Requires the Data Type and Address... C–4. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 1: V2100 C–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 2: Y20 C–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 3: T10 Current Value C–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 4: C54 C–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If the Host Software Requires an Address ONLY C–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 1: V2100 584/984 Mode C–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 2: Y20 584/984 Mode C–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 3: T10 Current Value 484 Mode C–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example 4: C54 584/984 Mode C–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix D: Using the D2–DCM with Modems
Introduction D–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Components D–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Configurations D–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Choosing a Modem D–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Set the D2–DCM Switches D–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Baud Rate & Parity D–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Delay Time D–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Delay Time Considerations for Networks with DL240 Slaves D–5. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Choose the Proper Cables D–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting a Modem to your Personal Computer D–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting a Modem to the D2–DCM D–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting a Modem to the DL240 D–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

iii
Table of Contents
Using the MDM–TEL D–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RS232 Connections D–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The MDM–TEL Setup Wizard D–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D2–DCM as Master D–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If You are Using a D2–DCM as Master D–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Using DirectSOFT32 D–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Creating a Modem Link D–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modem Setup D–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuring the Link D–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Data Communications Module, 2nd Edition, 2/03
D2–DCM
Data Communication
Module
In This Manual. . . .
— Introduction
— Building the Communication Cable
— Setting the D2–DCM Switches
— Installing the D2–DCM and Starting the Network
— Verification and Troubleshooting

Introduction
2
Data Communications Module, 2nd Edition, 2/03
Overview
This manual is designed to allow you to setup
and install your DL205 Data Communications
Module (D2–DCM). This is the only manual
you will need if you are using the D2–DCM as
an extra general purpose communication port
for your DL205 PLC system. If you plan on
using the D2–DCM as a network master or
slave for a DirectNET network, this manual
covers the basic steps for setting up the
D2–DCM and the RX/WX instructions needed
in your RLL program.
If you plan on using a personal computer as the network master, it may be helpful to
read the DirectNET manual first. In either case, the DirectNET manual can be
useful because it provides detailed descriptions of network configurations, various
cable connections, etc.
Depending on which products you have purchased, there may be other manuals that
are necessary or helpful for your application. These are some suggested manuals:
User Manuals
DDirectNET Network Guide part number DA–DNET–M
DDirectSoft32 Programming Software part number PC–DSOFT32–M
If you plan to use your D2–DCM to communicate with another PLC, you will need the
appropriate user manual for the other PLC.
If you plan to use your D2–DCM module as an interface to HMI or PC Control
software or to an Operator Interface panel, you will need to refer to the
documentation for that product.
If you need an additional communications port for your DL205 PLC and you
understand the basics of installing and programming PLCs, this is the right manual
for you. This manual gives you the information you need to set up an active port on
the D2–DCM module.
We strive to make our manuals the best in the industry and rely on your feedback in
reaching our goal. If you cannot find the solution to your particular application, or, if
for any reason you need additional technical assistance, please call us at
770–844–4200.
Our technical support team is glad to work with you in answering your questions.
They are available weekdays from 9:00 a.m. to 6:00 p.m. Eastern Time. We also
encourage you to visit our website where you can find technical and nontechnical
information about our products and our company.
www.automationdirect.com
The Purpose of
this Manual
Supplemental
Manuals
Who Should Read
this Manual
Technical Support

Introduction 33
Data Communications Module, 2nd Edition, 2/03
The “light bulb” icon in the left-hand margin indicates a tip or shortcut.
The “note pad” icon in the left–hand margin indicates a special note.
The “exclamation mark” icon in the left-hand margin indicates a warning or caution.
These are very important because the information may help you prevent serious
personal injury or equipment damage.
The beginning of each chapter will list the
key topics that can be found in that
chapter. 1
Conventions Used
Key Topics for
Each Chapter

Introduction
4
Data Communications Module, 2nd Edition, 2/03
D2–DCM Hardware
The following diagram shows the major D2–DCM components. The address
selection switches and the communication dipswitches are of special importance.
Status Indicators
(shown below)
Online/Offline Switch
Address Selection
Switches
RS232C/RS422
Communication Port
Base Connector
DIP Switches for
communications
and protocol parameters
TO: ON if a timeout has
occurred in the D2–DCM
Master Mode:
ON if master
OFF if slave
Send/Receive Data
Packet: FLASHING*
Module Power: ON Self Test Indicator: ON
Send/Receive Enquiry:
FLASHING*
Send/Receive Header:
FLASHING*
NK: ON if a NAK is
either sent or received
Status Indicators * During communications only
The DL205 Data Communications Module (D2–DCM) is a general purpose
communications interface that can be used in a DL205 system that has a
D2–240/250–1/260 Central Processing Unit (CPU). The D2–DCM cannot be used
with a DL230 CPU. The module can go in any base slot, except for Slot 0, which is
next to the CPU. This module is primarily used for three reasons.
DAs a network master or slave interface to a DirectNET network
DAs an extra general purpose communications port to connect a personal
computer or operator interface
DAs a network interface to a MODBUSRnetwork using the RTU protocol

Introduction 55
Data Communications Module, 2nd Edition, 2/03
Applications
The D2–DCM can be used as a network interface for applications that require data to
be shared between PLCs, or between PLCs and an intelligent device (such as a host
computer). The D2–DCM can be configured as either a master or slave station and
allows you to upload or download virtually any type of system data including
Timer/Counter data, I/O information, and V-memory information.
Request
DirectNET Slaves
Slaves respond to the master’s request
Response
PC or D2–DCM
master can
communicate with
DirectNET Slaves
DirectNET Masters
Issue requests to slave stations
Using a D2–DCM as a Network Master
The DL205 D2–DCM can be used with a
D2–240/250–1/260 CPU to serve as a
network master. Your CPU must have
firmware V1.8 or later. It cannot be used
with a DL230 CPU. (A master is the
network station that initiates requests for
data from other stations on the network).
You simply use special RLL instructions (RX
and WX) inside of your RLL program to
initiate the data exchange. The D2–DCM
takes communication requests issued by
the PLC program instructions and
automatically converts these requests into
network commands that read data from or
write data to another network station.
Possible Slaves
DD2–240/250–1/260 CPU (bottom
port)
DD2–240/250–1/260 w/ D2–DCM
DD3–330 or D3–330P w/ DCU
DD3–340 (either port)
DD4–430 (bottom port)
DD4–440 (bottom port)
DD4–450 (phone jack or bottom port)
DAny DL405 CPU w/ D4–DCM
The PLC program is really very simple and only requires a few instructions. Appendix
A provides an overview of the instructions. Or, see the DirectNET Manual for network
details.
Using a D2–DCM as a Network Slave
The D2–DCM can also be used with a
D2–240/250–1/260 CPU to serve as a
network slave station. It cannot be used
with a DL230 CPU. In this case, the
D2–DCM “listens” to the network for any
messages that contain the D2–DCM’s
address. The D2–DCM deciphers the
network commands, carries out the
request to read or write data, and sends
confirmation and/or information to the
master station.
Possible Masters
DD2–240/250–1/260
w/ D2–DCM
DD3–340 CPU (bottom port)
DAny DL405 CPU w/ D4–DCM
DD4–450 CPU (bottom port)
DHost computer w/DirectSOFT
DSData Server
As a DirectNET
Interface

Introduction
6
Data Communications Module, 2nd Edition, 2/03
As an extra communication port, the D2–DCM supports the DirectNET protocol just
like the bottom port on the D2–240/250–1/260 CPU, but at higher baud rates. In
general, if you can connect a device to the bottom port on the D2–240/250–1/260
CPU, then you can also connect the same device to the D2–DCM. These devices
can be a variety of things, such as operator interfaces or personal computers.
Since the D2–DCM does not require any programming, you can simply set the D2–DCM
communication parameters, connect the appropriate RS232C or RS422 cables, and start
transferring data.
Quickly add extra
communication ports*
* Number of D2-DCMs is limĆ
ited by the available power
budget
The D2–DCM can be used as a slave interface to connect your DL205 system to a
MODBUSnetwork using the MODBUSRTU protocol. The host system must be
capable of issuing the MODBUScommands to read or write the appropriate data.
Appendix C provides additional information on using the D2–DCM as a
MODBUS slave interface. This manual does not describe the MODBUSprotocol.
We recommend that you reference the Gould MODBUSProtocol Reference Guide
(P1-MBUS-300 Rev. B) for details on the protocol. There may be more recent editions
of this manual, so check with your MODBUSsupplier before ordering the
documentation.
MODBU  Network using RTU Protocol
Network
lave
As a slave station....
responding to network reĆ
quests
DL205 Slave
with D2–DCM
Network
lave
MODBUS Master
As an Extra
Communication
Port
As a MODBUS
Network Interface

Introduction 77
Data Communications Module, 2nd Edition, 2/03
Specifications
Operating Temperature 32°F to 131°F (0°to 55°C)
Storage Temperature –4°F to 158°F (–20°to 80°C)
Operating Humidity 5 to 95% (non-condensing)
Air Composition No corrosive gases permitted
Vibration JIS C0040
Shock JIS C0041
Voltage Isolation 1500 VAC, 1 minute duration
Insulation Resistance 10M ohms at 500 VDC
Noise NEMA ICS3–304
Power Budget Requirement 300ma @ 5 VDC
Maximum number of modules limited only by power budget
CPU Required D2–240/250–1/260 minimum
firmware V1.8 or later
Location of module CPU base only
any slot except Slot 0 or CPU slot
Interface Serial RS232C / RS422
half-duplex, DTE, Asynchronous,
8 bits/character, odd or no parity
Baud Rates 300 to 38.4K baud, switch selectable
Maximum Distance RS232C – 49ft (15 meters)
RS422 – 3300 feet (1000 meters)
Protocol DirectNET1
K-sequence (proprietary)
MODBUSRTU
Diagnostics Automatic check of ROM/RAM,
communications, switch settings,
and LEDs
Note 1: Also compatible with Hostlink and/or CCM2 protocols. These names were used by previous vendors of
compatible Koyo designed products.
Environmental
Specifications
Operating
Specifications

Introduction
8
Data Communications Module, 2nd Edition, 2/03
Using your D2–DCM– Five Steps
STEP 1. Familiarize yourself with the
communications options of
D2–DCM in the Introduction.
STEP 2. Build the communication cable
that fits your needs.
STEP 3. Set the D2–DCM switches.
(Baud rate, parity, etc).
STEP 4. Install the D2–DCM in any slot
except for Slot 0, which is next to
the CPU.
STEP 5. Verify correct network operation
by using the indicators and the
troubleshooting chart.
witches
Install
Verify (Troubleshooting)
Cable

Building the Cable 99
Data Communications Module, 2nd Edition, 2/03
Building the Communication Cable
There are several considerations that help determine the type of cable needed for
your D2–DCM application.
1. Will the D2–DCM be physically connected in a point-to-point configuration
or multi-drop configuration?
2. What electrical specification is best for your application? RS232C or
RS422?
3. What is the cable schematic?
4. What are the relevant cable specifications?
5. What installation guidelines are necessary?
The next few pages discuss these considerations in detail.
Tip: If you need a quick test cable you may want to try our FA–CABKIT which allows
you to quickly build several different types of cables. (See page 15 for more
information). If you’re fairly comfortable with network or communications cabling
requirements, see Appendix A for detailed diagrams.

Building the Cable
10
Data Communications Module, 2nd Edition, 2/03
The D2–DCM can be used in either a point-to-point or multi-drop configuration. A
point-to-point connection only has two stations, a master and a slave. Use the
point-to-point configuration to connect a personal computer, an operator interface,
or an intelligent device to a single D2–DCM. You must also use this configuration
when you want to connect a DirectNET master station to a single DirectNET slave
station.
Use the multi-drop configuration to connect one master to two or more slaves (90
slave maximum).
or
Point to Point
DCM
DL205 Master DirectNET PLC Slave
D2–DCM
DirectNET SlavesDirectNET
Masters
D2–DCM
Multi-drop
or
Consideration 1:
Physical
Configuration