Here are some of the more commonly asked questions pertaining to our DL205 family of PLCs. For a more complete list, go to the Technical Support page of our Web site.

Question: Is the DL205 system expandable?

 PLC systems with a D2-250-1 or D2-260 CPU can be expanded using the D2-EM Expansion module and D2-CM Expansion Controller modules. Reference the DL205 User’s Manual Chapter 4, Local Expansion I/O section, for complete details.

DL205 PLCAnother method of expansion is by using remote I/O with a D2-240, D2-250-1 or D2-260 CPU. The D2-240 requires the D2-RMSM Remote Master module. A total of 896 I/O points are configurable when using two Remote Master Modules with 7 slave units per module. The D2-250-1 and D2-260 CPUs can use either the D2-RMSM module or the bottom port of the CPU. A total of 2048 I/O points are available when using up to 7 Remote Master Modules plus the CPU port, with 7 slaves per master. The D2-230 can not be expanded beyond the local rack.

Question: Can I override the inputs and outputs in a DL205 PLC? 

 Yes, when using DirectSOFT programming software connected to the CPU. The D2-240, D2-250-1 and D2-260 CPUs all support bit override. To enable bit override go to VIEW>OPTIONS from the DirectSOFT menu bar. Select the Data View tab and check Override Bits. Next, from the DirectSOFT menu bar, select DEBUG>DATA VIEW>NEW/OPEN. Select the bit to be overridden and use the on/off button to change the state of the bit. NOTE: Be sure to disable all override bits before returning the PLC to service.

The D2-230 does not support override. You can turn bits on or off using Data View. Inputs bits will only be overridden for a single scan since the PLC will update the image register on the next scan and change them back to their actual state. NOTE: Only inputs can be overridden using this method. The outputs will be the result of the rung that controls them. As another method, you can directly control outputs by loading a program that consists of an END statement only. Using Data View you can select the bit and use the on/off button to change the state. You cannot control inputs using this method.

Question: How can I reset my processor back to factory defaults?

Answer: Resetting the processor to factory defaults is a two step process. First, clear the processor memory by selecting PLC>CLEAR PLC MEMORY from the DirectSOFT menu. Next, initialize the scratchpad by selecting PLC>SETUP>INITIALIZE SCRATCHPAD. NOTE: Initializing the scratchpad will reset the system V-memory to default and will clear parameters such as retentive ranges, DV-1000 setup parameters, etc.

Question: When using PID control with a D2-250 CPU, the process variable values are incorrect. What am I doing wrong?

Answer: It’s probably caused by a data format mismatch. The Setpoint Value (SP), the Process Variable (PV), the Bias (Integrator) and the Control Output Value (CO) all use a binary format. If using the pointer method in your ladder program for configuring the analog signals, you can specify either BCD or Binary format. If configured using BCD, you must do a BIN conversion before OUTing the value to Word+3 (PV). Also, make sure that Word+5 (CO) is in the proper format. For more information reference the loop table specifications located in the PID chapter of the User Manual.

Question: What causes the Control Output on a PID control loop to not function?

Answer: Most likely you haven’t entered a high limit for your Control Output when configuring the PID setup. The default value is 0 with a maximum of 4095 binary. You must enter a value other than 0 in this field (Word+31) using the PID setup or in your ladder program. Check your Control Output word (Word+5) to see if you are getting an output value. If this value is changing and you still have no control output then verify that you are writing this value to the analog output card or the Time-Proportioning ladder for discrete output control.

Question: What causes the Setpoint Value in a PID loop to change when switching from Manual to Auto mode using PID View or ladder? 

Answer: You are probably in Bumpless Transfer Mode 1. In this mode, the Setpoint Value is forced to the Process Value on a manual to auto transition. You should use Bumpless Transfer Mode 2 if you do not want this to occur. This is covered in the Bumpless Transfer section of the PID chapter in your User Manual.

Question: Can the DL205 be used in a Modbus network?

Answer: Yes, if Modbus RTU (hex) is the supported protocol, the D2-240, D2-250-1 and D2-260 CPUs can all be used in a Modbus network. The bottom ports of the D2-250-1 and D2-260 can be configured as a Modbus master or slave. The D2-240 bottom port supports slave mode only. Also, our Data Communications Module (DCM) can respond as a Modbus slave when used with the D2-240, D2-250-1 or D2-260 CPU. The D2-230 cannot be used on a Modbus network.

Question: Does the DL205 support Profibus protocol?

Answer: Yes, using the H2-PBC Profibus Slave Base Controller. This unit operates as a slave only and replaces the CPU in the DL205 rack. For more detail, view the H2-PBC-M manual in the documentation section of our Web site.

Question: Does the DL205 base power supply have an internal fuse?

 Yes, it contains a 2A 250V slow-blow fuse. However, the fuse is non-replaceable so an external fuse is recommended.

Question: My DL205 PLC won’t recognize my I/O module(s). What could be the problem?

 It’s very possible that your firmware is too old. When a new module is introduced, the PLC firmware must be updated to recognize the new module.

Question: Where can I obtain the most current firmware for my CPU? 

 All CPUs ship with the most current firmware. If you have an existing CPU that needs to be updated to accept a new module or feature or improvement, go to the following Firmware Page on our website to check for availability of downloadable firmware: or go to Technical Support -> Software/Firmware Downloads -> Firmware. You must download the Koyo Support Tool and the appropriate firmware binary for your CPU. Unzip these files to extract the firmware binary, and the Koyo Support Tool installation file. Install the Koyo Support Tool as you would any other software program. It will be listed as Firmware Update Tool under Start -> Programs. Run the Firmware Update Tool. It has a Wizard mode and a single page mode. Most users will find the Wizard mode easier to use. It will take you step-by-step through the process of updating the firmware in your CPU. For CPUs that have their firmware on a PROM chip (D2-230 and D2-240), you must call AutomationDirect Tech Support for a new firmware chip. These will be sent to you free of charge.

Question: Does the DL205 support an encoder input and drive a stepper motor simultaneously?

 There are two high-speed counter modules available for the DL205. The D2-CTRINT, which can only perform one of the functions, either high speed pulse in or high speed pulse out, and must occupy the slot next to the CPU (slot 0), therefore only allowing one module per CPU system. The D2-CTRIO, which can handle both functions simultaneously, allows for multiple modules used per CPU system (dependent on power budget), which can reside in any slot with the exception of slot 0.

Originally Published: June 1, 2007