[ed_denu]

The ability of a PID to drive multiple ssr's is based on the load characteristics of the PID and SSR's being used. The PID outputs driving the SSR(s) will have a maximum load rating. In the case of my PID it's 40ma. So as long as the SSR input current requirements combined do not exceed 40ma then it could handle 2 ssrs.

As for the L1 I'm not real sure what the question is. The SSR is just a relay(switch) capable of supporting much higher loads then the PID itself could manage. The T1 in this case is the supply side of the SSR output. The L1 is the load side going to the elements. Without the L1 connection the elements would never be energized.

The SSR should have come with details of it's input voltage requirements and load carrying capabilities. As for wiring the SSR there aren't many options. The (2) input terminals accept voltage from the controller or PID(usually polarity sensitive) and the (2) load side terminals get (1) connected to the source and (1) connected to the load(elements).