Northants declared overnight, 54 runs in arrears, and struck immediately as Zain Ul Hassan played no shot and was bowled by Luke Procter for two.
Procter’s probing opening spell was followed by an even more threatening one from Justin Broad, as Tribe (24) suffered a rare relatively cheap dismissal, given out caught down leg side.
Broad then got prodigious bounce to force an edge from Sam Northeast on 20.
But Ingram brought his usual air of serenity to proceedings with the exception of a boundary chance on 30, when Nirvan Ramesh fell awkwardly underneath the high ball and limped off injured.
Ingram hit the next two balls for four to celebrate the let-off and moved past the 1,000 runs landmark to his half-century off 66 balls, the 10th half-century or better in as many Championship matches.
Kiran Carlson was caught behind for 39 off a sharply-turning ball from Harrison, but their stand of 88 had already taken the lead to 200 despite the pitch playing tricks for seamers and spinners.
Ingram had punched 11 fierce boundaries when he looked surprised to be given out caught at slip off Harrison, and a limping Ben Kellaway, batting with a runner because of a calf injury, was bowled round his legs for 18 by the leg-spinner.
The broad defensive bats of Chris Cooke (40 not out) and Timm van der Gugten ensured the draw, with Van der Gugten caught for 21 in the final session to give debutant seamer Ben Whitehouse the joy of his first wicket before handshakes.
Northants coach Darren Lehmann told BBC Radio Northampton:
“It would have been a brilliant game [without the lost time], both sides trying to win. The wicket wasn’t a 460 wicket, but we fought back well and Glamorgan the same, both batting sides went really well and I thought it was a great game.
“Really pleased with the effort because with Finals Day coming up, everyone’s looking ahead and we’re trying to stay in the moment and get better at championship cricket, I think we did that.
“That’s probably the best [batting intent] I’ve seen this year, Saif Zaib with six centuries has been unbelievable, good to see Ricardo Vasconcelos get some runs, and Procter’s been fantastic opening.
“Nirvan [Ramesh] bowled well in the first innings and though he didn’t come back out [through injury] I expect him to play the next couple of games.”
Glamorgan coach Richard Dawson told BBC Sport Wales:
“We knew we were going to have to bat the day out, so we did the job required. Colin Ingram, getting 1,000 runs today, just keeps on producing.
“I’ve talked about setting up the game in the first innings, going big, and Asa got that double century to set us up nicely. He loves getting runs, he loves batting, and hopefully he can continue [his form] for a couple more weeks.
“It’s not just a simple technique, he’s got a simple mindset and game plan, he learns quickly and works hard, so it’s been nice to see him get those runs, hopefully people sit up and watch. We want our best young players playing for Glamorgan so it’s good to have him with us for the foreseeable future.
“[On promotion chances] We keep on going, the same messages of doing the basics well and hopefully we’ll get the results we need.”
