Fasthotrod
Member
Good afternoon everyone.
A while back I asked for input regarding the use of a PLC to act as a 'data concentrator' as an interface between a new power system and an old building monitoring system. The original thread can be found here:
http://www.plctalk.net/qanda/showthread.php?t=34611
Since then, I have purchased the following:
One AD DO-06AR PLC: 120VAC w/Relays
Two FO-08DAH-2 8 Channel Analog Output cards
ZipLink DN-15TB Communications Connector Module
ZipLink ZL-DN15TB -CBL
One DL-06 Programming Cable
One DirectSoft5 Software package
One Users Manual
I installed the software and was able to communicate with the PLC. I wrote a quick program and made some outputs switch when given an input. (Hold the applause... I'm new at this. )
So now I think I am ready to dive into this project. (Okay... I know I'm not ready, but I don't have a choice but to dive in. )
I have been looking at data in my generator controller (Kohler DEC 550) using the Monitor III software on my laptop. My laptop is connected (RS-232) to the controller right now, but I can switch it to 485 using a dongle. (I'll be testing this to make sure I have my RX/TX lines setup properly between my laptop, PLC, and hardware points.)
Anyway, I have the documentation for the power system equipment, so now I need to figure out how to grab the data I need. I'll throw out an example and maybe you guys could point me in the right direction?
Example: I want the PLC to read what the generator output voltage is (0-150 VAC) and provide me an analog output (0-5 VDC).
The Kohler documentation states that this information is located in the following location in the generator controller:
Register: Data Description: Access: Data Type: Range/Units:
40004 ..... L1-L0 Voltage ... RO ... WORD ..... Volts AC
40005 ..... L2-L0 Voltage ... RO ... WORD ..... Volts AC
40006 ..... L3-L0 Voltage ... RO ... WORD ..... Volts AC
I need to have a rung in my PLC program that requests this data, so looking in my PLC manual on page 5-204 it says to do this by using a MODBUS Read from Network (MRX) command. The question is: How?
I need to have a rung that tells the CPU to send a command on out on Port 2 (K2?) to slave device #1 (DEC 500 controller: K1? ) and have it perform a Function Code: 03 - Read Holding Registers. I went to the end of the rung and added a MRX box, but I am confused as to how to configure it.
Does anyone have any example programs that I could use to learn from?
Tips, hints and suggestions are greatly appreciated. Thanks in advance!
Mark
A while back I asked for input regarding the use of a PLC to act as a 'data concentrator' as an interface between a new power system and an old building monitoring system. The original thread can be found here:
http://www.plctalk.net/qanda/showthread.php?t=34611
Since then, I have purchased the following:
One AD DO-06AR PLC: 120VAC w/Relays
Two FO-08DAH-2 8 Channel Analog Output cards
ZipLink DN-15TB Communications Connector Module
ZipLink ZL-DN15TB -CBL
One DL-06 Programming Cable
One DirectSoft5 Software package
One Users Manual
I installed the software and was able to communicate with the PLC. I wrote a quick program and made some outputs switch when given an input. (Hold the applause... I'm new at this. )
So now I think I am ready to dive into this project. (Okay... I know I'm not ready, but I don't have a choice but to dive in. )
I have been looking at data in my generator controller (Kohler DEC 550) using the Monitor III software on my laptop. My laptop is connected (RS-232) to the controller right now, but I can switch it to 485 using a dongle. (I'll be testing this to make sure I have my RX/TX lines setup properly between my laptop, PLC, and hardware points.)
Anyway, I have the documentation for the power system equipment, so now I need to figure out how to grab the data I need. I'll throw out an example and maybe you guys could point me in the right direction?
Example: I want the PLC to read what the generator output voltage is (0-150 VAC) and provide me an analog output (0-5 VDC).
The Kohler documentation states that this information is located in the following location in the generator controller:
Register: Data Description: Access: Data Type: Range/Units:
40004 ..... L1-L0 Voltage ... RO ... WORD ..... Volts AC
40005 ..... L2-L0 Voltage ... RO ... WORD ..... Volts AC
40006 ..... L3-L0 Voltage ... RO ... WORD ..... Volts AC
I need to have a rung in my PLC program that requests this data, so looking in my PLC manual on page 5-204 it says to do this by using a MODBUS Read from Network (MRX) command. The question is: How?
I need to have a rung that tells the CPU to send a command on out on Port 2 (K2?) to slave device #1 (DEC 500 controller: K1? ) and have it perform a Function Code: 03 - Read Holding Registers. I went to the end of the rung and added a MRX box, but I am confused as to how to configure it.
Does anyone have any example programs that I could use to learn from?
Tips, hints and suggestions are greatly appreciated. Thanks in advance!
Mark