# RACO Catalyst Modbus Addressing questions **URL:** \ **Category:** Ignition\ **Tags:** modbus\ **Created:** [May 7, 2025, 9:29pm UTC](https://forum.inductiveautomation.com/t/raco-catalyst-modbus-addressing-questions/106009 "2025-05-07T21:29:47Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![jordan.richardson](https://avatars.discourse-cdn.com/v4/letter/j/94ad74/32.png) [@jordan.richardson](https://forum.inductiveautomation.com/u/jordan.richardson)\ **Post date:** [May 7, 2025, 9:29pm UTC](https://forum.inductiveautomation.com/t/raco-catalyst-modbus-addressing-questions/106009/1 "2025-05-07T21:29:47Z")
Before I get too far down a rabbit hole I'd like to see if it's even possible to communicate to a RACO C10-020-1450E. The support page for the connection guide can be found [here](https://www.racoman.com/support/catalyst-ethernet-option-setup-version-5-vo3?srsltid=AfmBOoqPY3CJPBCepc9-SWgJ71GqmUHz6EZU9T--_9eKlJ9kQkAiLevI). The main point of concern from that document is: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/e/1e574514acf3696ca97f95c0a780733448de62cc.png) To start, I am able to successfully connect to it using the Modbus Driver on my local Ignition instance. However when I try and write to a coil either using C1 or trying to map some addresses in with a node ID of 2 (I did this because of the SNA style from the guide?) I get the following error: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/2/7/2790cb52d66d6bfdf92bdf121e0a7795617c3d34.png) I'm just curious if the somewhat odd addressing style might be my issue, or if I'm missing something even more obvious? ---
**Author:** ![David\_Stone](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/david_stone/32/79749_2.png) [@David\_Stone](https://forum.inductiveautomation.com/u/David_Stone)\ **Post date:** [May 7, 2025, 9:35pm UTC](https://forum.inductiveautomation.com/t/raco-catalyst-modbus-addressing-questions/106009/2 "2025-05-07T21:35:05Z")
That "Modbus" is terrible. Definitely don't use that. The unit supports Ethernet/IP, use the Automation Professionals Ethernet/IP driver and connect as if you were a PLC, at least thats a standard method. If you must insist on trying Modbus, Automation Professionals also have a Modbus driver that has a lot more features for oddball stuff than the IA one. ---
**Author:** ![jordan.richardson](https://avatars.discourse-cdn.com/v4/letter/j/94ad74/32.png) [@jordan.richardson](https://forum.inductiveautomation.com/u/jordan.richardson)\ **Post date:** [May 8, 2025, 12:56pm UTC](https://forum.inductiveautomation.com/t/raco-catalyst-modbus-addressing-questions/106009/3 "2025-05-08T12:56:23Z")
I definitely agree that this flavor of modbus is not the best. However, I the facility will not go for purchasing a $1000/$500 module for this one off application. I might have to write it off and try to pull to a local PLC and configure it over EIP. I was just hoping I'd be able to do it directly through Ignition without additional modules. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [May 8, 2025, 1:04pm UTC](https://forum.inductiveautomation.com/t/raco-catalyst-modbus-addressing-questions/106009/4 "2025-05-08T13:04:57Z")
Try C2 instead of C1? That seems like the first address given you have to multiply every address by 2 (`1 * 2 * offset`). ---
**Author:** ![David\_Stone](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/david_stone/32/79749_2.png) [@David\_Stone](https://forum.inductiveautomation.com/u/David_Stone)\ **Post date:** [May 8, 2025, 1:08pm UTC](https://forum.inductiveautomation.com/t/raco-catalyst-modbus-addressing-questions/106009/5 "2025-05-08T13:08:41Z")
TBH looking at the "Catalyst" unit, you would be better off deleting it entirely and replacing it with Ignition. From it's advertising on the website, it is a glorified alarm notification system with a lot of non standard interfaces. For the price that someone paid for it (current pricing I could find is $7500 USD) , you probably bought 3 standards compliant units that integrate just fine with lots of other systems. ---
**Author:** ![jordan.richardson](https://avatars.discourse-cdn.com/v4/letter/j/94ad74/32.png) [@jordan.richardson](https://forum.inductiveautomation.com/u/jordan.richardson)\ **Post date:** [May 8, 2025, 2:12pm UTC](https://forum.inductiveautomation.com/t/raco-catalyst-modbus-addressing-questions/106009/6 "2025-05-08T14:12:29Z")
That was also kind of where I was going with the purchase of the EIP module. We already have a 'newer generation' of TTS at other facility's that's monumentally cheaper, but this CATALYST was 'free' from a decommissioned line.