Per weapon_data.csv, Paladin PD ("guardian") does its damage in a single burst: 1000 DPS, 0.2s burst size, 0.1s burst delay, 1 ammo used, 20 ammo max. This is consistent with the data format for the other weapons and with the in-game weapon card; thus, as far as I can tell the "5 beams" is simply cosmetic. Hit strength for beams is calculated as 50% of the actual beam DPS value from the game's data.
In the case of Paladin PD, the game does split them up into 5 individual beams which can hit or miss independently (such as if some beams happened to graze a target while the others didn't), and they thus end up with only 1/5 of the hit strength. This is not directly coded in weapon_data.csv. Rather, in guardian.wpn, the fact that there are 5 turrets defined (the turretOffsets, turretAngleOffsets, hardpointOffsets, and hardpointangleOffsets parameters) automatically tells the game to split the beam into 5 components with each getting 1/5 of the beam's damage and hit strength. So in this case, each beam's hit strength is only 100. This makes it so that the Paladin PD can have high DPS, yet low armor penetration. This can be verified via testing*.
This is used to great effect in the Sylphon mod, where the large energy weapon Radiant Dawn Emitter has 600 DPS for 600 flux with 1000 range and only costs 19 OP. Normally that would be too strong; however, it's split into 8 beams, so it only has 37.5 hit strength when it would normally have 300 hit strength. Thus the fact that it's a beam (soft flux) limits its utility against shields, while its low hit strength limits its utility against armor and hull, limiting its power, allowing it to have massive "on-paper" stats. It's basically 8 tactical lasers tied together.
Part of the issue here is that not only is how armor works rather opaque, but the hit strength of a weapon is not given anywhere directly in the game. For projectiles it's fairly easy to figure out (the hit strength is the same as the damage per shot), but for beams (and especially burst beams) there's no alternative except to go digging into the game files. Then there's the whole "multiple beam" thing to consider as well. It should be easy enough to add a "hit strength" field onto the weapon stat card, especially when this is a very important stat for weapons.
*Testing notes:
Spoiler
This can be verified in-game by removing most of the turret data so that there is only 1 turret. The Paladin PD's damage against armor will noticeably increase. For example, setting the weapon to a 1-second burst (a 0.2-second burst is too short, leading to differences in how many damage ticks each burst get), it will normally do around 142 damage to the low-tech practice target (1750 armor), and around 212 damage with HEF on. This is basically the 15% minimum damage (which would theoretically be 150 and 225, respectively). But if Paladin PD were reduced down to 1 turret by changing the four above parameters, it will do around 218 damage, around 440 with HEF on, against the same target, when the theoretical amounts would be 222 and 450 damage, respectively. (Beams always do slightly less than the theoretical amounts due to various game engine properties.)
Edit: As a side note, HSA makes the Plasma Drivers in the Legacy of Arkgneisis mod
very attractive next update. Depending on how much the Doom is nerfed (and how much the cryoblaster is nerfed), the Cabal Aurora or possibly the SWP Gorgon may become a very powerful HSA flagship.