default gateway

If it really does not need to route, the you don't need to code one unless it requires you to.

If you have to code one and you really, really don't want/need it to route then code it as a IP address that does not exist  and document that IP address should NEVER be used.

However, just remember the alarm system does not have a valid default route, you have NO network access to it unless you are using a host that is on the same IP subnet.

... or if you use SOURCE NAT when connecting remotely to that network.

A DG needs to be configured for the alarm system. I have the alarm systems and its devices in its own vlan 200 (10.10.200.0/24). So I setup the DG as 10.10.200.1 which is the HSRP IP address for my 2 cores switches (10.10.200.2 and 10.10.200.3). I think that sounds correct. Any thoughts?

Yes. That is what I got. I configured hsrp on my core switches with 10.10.10.1 like I mentioned in my previous thread. Thx

Please re-read your  previous posts.  You seem to be interchanging VLAN's and subnets.

In your original post you stated the alarm system was on VLAN 10, 10.10.10.0/24 and you had VLAN 200, 10.10.200.0/24.

In your prior  post you stated you were going to configure the alarm system to point 10.10.200.1, which is NOT the subnet you originally stated the alarm system is on.

I pointed this out and then you stated, yes, that is what I said 10.10.10.0/24?

So which is it, is the alarm system on 10.10.10.0/24 or on 10.10.200.0/24?  

If it is on 10.10.10.0/24, what default router did you code for it?

Yes sorry. They keep changing the subnets on me. Let say that the alarm system is 10.10.10.0/24. I have the DG as 10.10.10.1. My cores have hsrp as 10.10.10.1 and each of the core has 10.10.10.9 and 10.10.10.10 as the SVI IP address.