Connecting the shield of signal cable

I depends on what is connected to it. The equipment manufacturere will avise the method with the equipment

Both can be done , this depends on instrument configuration.

the cable has 2 cores or three wires or only one core.

one core, you have to connect shield layer to ground and the ground connects directly to po9wer supply ov and earth. unbalance structure

2 core, you can let the shield layer suspending.(empty, link to nothing) at another terminal, the shield layer links to ground. balance structure

3 cores, pin1 link to ground, a nd pin2,3 link to signals. sometimes, these two wires have 12v or 48v voltage to supply device like phone power. now the shield can connect ground or suspending. at another terminal link to ground.

Do read manual to prevent from faulty.

If the power supply 0V is earth grounded, the two methods are functionally identical.

However, if the power supply is floating (all outputs ungrounded), or connected to earth ground through a resistor or other limiting component, you must connect the shield directly to earth ground.