Can we use the spot prices to trigger a buy/sell in the futures contract?

I generally do my analysis on the cash segment but trade in the futures. Now since, the difference between cash and futures keeps varying during the day its difficult to place a limit order on futures when you are benchmarking against the cash price.

Is there any way of triggering a buy/sell on futures as soon as the cash price is reached.

For ex: I wish to buy M&M futures (at whatever price its trading) when the cash (spot) price hits 1,400.

Currently, I have to keep looking at the screen and then place a market order when it happens. Please advise

One can automate it by using any programming language using brokers API. If you are not a coder then only way is to place it manually. In India no broker supports conditional order type that is if set condition is triggered then only order should be placed directly into system. Conditional order type should have solved your issue.