[ts-7000] DIO output pin short-circuit protected?

["Mike Dodd" <>]

The TS-7250 manual says, about the DIO port, "When these DIO pins are 
configured as outputs, they can source 4 mA...."

Are these pins protected against a direct connection to ground when configured 
as outputs? I.e., is there an internal resistor or current-limiter on each pin?

I have an application that interfaces the 7250 to an HVAC system, using its 
24VAC signals to control dry-contact relays wired to the DIO port.

Since the HVAC can actuate these relays at any time, I'm concerned that one or 
more might be connecting the DIO pin to ground when the 7250 is powered-on, 
before my program launches and configures the pins as inputs. This will be only 
a brief period, but I don't want to take a chance of zapping the DIO port.

Am I safe, or should I include a series resistor to the relay contact?

Thanks.

--- Mike




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