Radio Serial Communications and AD DL06

waggs

Member
Join Date
Mar 2004
Location
Yucaipa, CA
Posts
108
Hey Group...
After using the DL06 and getting rf modems to handshake properly between Master and Slave I'm wondering if anyone has used rf modems (any brand, but we are using MaxStream) to directly remote program from PC to PLC? I tried a time or two without success and I haven't found anything while searching threads here...maybe I missed something. Tried AD FAQ also...no luck. Sorry if the question is fuzzy. Hope you all enjoyed the holidays.
Bob (WD8BDN)
 
Bob,

We have the Maxtream units for this purpose, but not me personally. The one who did it was a summer time student. I remember him spending some consirable time at it also. I think the issue was with matching up the baud rate & timeouts between the PC, Radios, & PLC. The key word I recall was "Latency issues".. (Sorry about the fuzzy answer..). If you cannot resolve it, let me know and I'll give him a call & pick his brain.
 
Thanks Mike...that gives me a place to start. If I'm successful I'll post some data for others. Thanks again, Mike
 
I have used Phoenix Contact’s 900MHz radio modems in a Master/Slave network where I could also program (and go online) the remote PLC through the radio modem. Although it’s possible, even at 9600 baud the download takes a long time due to the delays that have to be set in the comm port. Here are the port parameters that I use –

Protocol: DirectNet
RTS On: 50mS
RTS Off: 20mS
Baud: 9600
Stop Bits: 1
Parity: Odd
 
Latency is the keyword. You will most likely need to up the timeouts and retries in DirectSoft as well as setting up the PLC port similar to what Tark posted. You might need to up these values as well. It will be slower than a cable connection most likely.

You also might need to switch the Radio Parameters to an "acknowledged mode" as well. This resends the RF packets only if an ACK is not received back from the receiving radio.
 
Tark and icky812 (btw, who'd I talk to at AD?)...thanks for the info guys. I haven't had a chance to try this stuff out as the programming is in debug but it is something that will come down the road in a week or so. Our use may not be unique but it will make the job (my) easier. Using a DL06 in our windmills here as a master and slave and being able to rf remote to the master at the top of the mill will save me from hauling my laptop and associated stuff, not to mention my butt, up to the top. Thanks again guys.

Bob (WD8BDN)
 
waggs said:
Using a DL06 in our windmills here as a master and slave and being able to rf remote to the master at the top of the mill will save me from hauling my laptop and associated stuff, not to mention my butt, up to the top. Thanks again guys.

Bob (WD8BDN)

There can be only one master in a network. So you cannot make an rf connection to the PLC which is set-up as the master. You can make rf connection with only the PLCs which are set-up as slaves.
 
Tark said:
There can be only one master in a network. So you cannot make an rf connection to the PLC which is set-up as the master. You can make rf connection with only the PLCs which are set-up as slaves.

Tark, Please clarify that for me.
 
Well Bob didn’t say what type of communication he is using, I assumed he was using RS-232. If he is using Ethernet he should have no problem communicating with either the Master or Slaves in the network. If he is using RS-232 then he would have to be at the Master site in order to program the Slaves. On an RS-232 network there can be only one Master, therefore you would have to be at the Master location and disconnect the Master PLC and use it’s modem and then you could use this modem to program the Slaves.
 

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