Robinson admitted his the charge which stated that “on two separate occasions” in or around the changing rooms, he acted in “an improper manner, and used abusive and insulting words and behaviour towards a match official”.
Seven Salford players were also booked during the game, which was their third successive defeat.
Robinson told Radio Manchester after the game: “I can’t wait to see him [referee Atkinson]. I’m going to question him an awful lot of who he is because some things got said before the game, which I can’t say as I don’t want to get myself in trouble, but things were said before the game that referees should not say.
“I will be reporting it. I will be asking why it was allowed to happen.”
Robinson was also sent off in his first match in charge of Salford, in January.