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Thread: Jace and Modbus

  1. #14
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    Quote Originally Posted by davem View Post
    An oversight of the ignorant kind - I've never used MODbus through the RS-232 port (but I'm glad I know that now - I know some switchgear spits out MODbus points via 232...now if I can just get my JACE within 50' of the switchgear...)
    I'm just throwing that out.

    Sure, it may not fit every app, but on a new install, like with an Aerco BMS, you could get the BMS set close to a JACE and run the RS-485 the longer distance to the individual boilers.

  2. #15
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    Of course! I don't why I didn't think of that...a rs-485 converter!! Geez, do I look silly...
    But it's all about getting the most functionality out of a given JACE model, so knowing I've got that port available is a nice little thing to remember.

    (Now if I could just figure out why the 232 port on a JACE-4 is an RJ-45 jack...rhetorical question - don't answer that...)

  3. #16
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    I just did a large data center job, integrating all kinds of Mod Bus stuff; among a few other protocols into a Jace 6.

    The only issues were that some of the devices had fixed parameters such as the baud rate and the parity were different then the others

    I ended up having to using (2) 485 expansion cards to bring in the 3 Mod Bus RTU'S, N2 and Bachnet MSTP into the Jace 6, running out of places to plug stuff into the last modbus connection ended up being ModBus TCP/IP that was tied in with the SNMP stuff.

    The long and short of it......

    Make SURE you have as much information as possible on the field devices This job information was hard to come by and once we discovered that these devices had fixed parameters, we ended up having to re-run the bus(s) to accommodate

    Other then that, its a cake walk

  4. #17
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    Jan 2002
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    Fort Worth\Dallas, Texas
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    Well I played with this today. I got the Jace talking to the Carel gateway no problem, but the gateway does not seem to be talking to the APC units very well. Not much info on this stuff.

    I will bang my head on it some more tomorrow.
    Go Rangers!

  5. #18
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    You do have the little configuration program on a disk, right? It offers a command line for reading and writing certain configuration parameters.

    Also, be sure to crack the box open, and confirm that the jumpers are set on the correct pins for 422 vs. 485 communication.

  6. #19
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    Quote Originally Posted by davem View Post
    You do have the little configuration program on a disk, right? It offers a command line for reading and writing certain configuration parameters.

    Also, be sure to crack the box open, and confirm that the jumpers are set on the correct pins for 422 vs. 485 communication.
    Thanks for the Info Dave. Yes the jumpers are set correctly and I did configure the gateway with the floppy. I set the gateway addy to 1, devices -2, baud -9600, bit -1 parity none. The alarm 2 led is rapid flashing which means it cannot see one or more of the units. The tx and rx leds will flutter every 3 or 4 sec. The two units are adrressed to 1 and 2 and 9600 baud.
    Go Rangers!

  7. #20
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    Quote Originally Posted by lwarren View Post
    Thanks for the Info Dave. Yes the jumpers are set correctly and I did configure the gateway with the floppy. I set the gateway addy to 1, devices -2, baud -9600, bit -1 parity none. The alarm 2 led is rapid flashing which means it cannot see one or more of the units. The tx and rx leds will flutter every 3 or 4 sec. The two units are adrressed to 1 and 2 and 9600 baud.
    From memory the gateway address should not be 1 as you have devices 1 and 2. Try setting gateway address to 3 and keep field device addresses as 1 and 2

    Barry

    **EDIT - I have checked my installation and I have 3 devices at 1,2, and 3 and my gateway device is 4. Try that. Also note that you may get warning LED on the gateway if once field device gets disconnected.

    Barry
    Last edited by gnomethang; 10-24-2008 at 09:30 AM.
    gnomethang
    _______________________________________________
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  8. #21
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    Quote Originally Posted by gnomethang View Post
    From memory the gateway address should not be 1 as you have devices 1 and 2. Try setting gateway address to 3 and keep field device addresses as 1 and 2

    Barry

    **EDIT - I have checked my installation and I have 3 devices at 1,2, and 3 and my gateway device is 4. Try that. Also note that you may get warning LED on the gateway if once field device gets disconnected.

    Barry
    Well I tried that and it still is doing the same thing. I talked to Carel and they said that the gateway address does not interfere with the device addresses because they are two separate networks. After talking with tech support at Carel and APC they don't know what the problem is. The units have to be talking to the gateway because the TX and RX lights are a constant rapid flash.

    As a test I reconfigured the gateway for one device and connected only on unit with a device address of 1. The TX and RX lights stayed constant flash and the Alarm2 led stayed flashing. I could disconnect the wires to the unit and the TX and RX would stop flashing. Connect them back and boom they are off and running again. Tried the same with the other unit and it did the same thing. I even went through all of the different baud rates.

    I am sending the gateway and both cards back for testing.

    By the way, what should my ping address start at? I have it set currently at
    40001.

    Thanks for the help.
    Go Rangers!

  9. #22
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    I've got my ping address set as hex:0.

  10. #23
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    Quote Originally Posted by davem View Post
    I don't think it's that complicated - I simply divided the incoming values by 10 before displaying them, and multiplied the outgoing setpoint values by 10 before writing them...
    Do you need the "Server" feature to write setpoints back to the ModBus device?

    Or is like a LON nvi and nvo?

  11. #24
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    The "server" license is used if you need the JACE to appear as a MODbus device on a MODbus network, "serving" up JACE data as MODbus data.

    In this particular case with the gateway, you can write to whatever MODbus registers support read/write functions. In my case, some of the higher 40xxx registers supported writing, for temperature and humidity setpoints.

  12. #25
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    This is my first modbus job, but so far I would have to say I am not a fan.
    Go Rangers!

  13. #26
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    My sentiments exactly - our MODbus experience was definitely not by choice, but simply a contractual requirement to integrate certain equipment. I think the ability to do this integration is nothing I'd go out of my way to capitalize on..."yeah, we can integrate that, but..."

    MODbus is actually a fairly simplistic protocol, which probably explains why manufacturers of everything from electrical meters to gateways to CO2 sensors support MODbus first, but also explains why it lacks all the "modern" features like auto-discovery. Fortunately, it also explains why it's quite robust. Once you get everything addressed correctly, there's not much to go wrong - messages are 'simple', timing is 'simple', etc.

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