Solenoid pen lift¶
Earlier terraPens used a solenoid to raise and lower the pen, rather than the stepper toolhead fitted to current machines.
For existing machines only
New terraPens are not supplied with a solenoid toolhead. This page is here for customers who already have one.
Everything else in this guide applies to you unchanged — setup, Wi-Fi, paper, homing, uploading, plotting, and stopping a plot. This page covers only the differences.
What is different¶
| Solenoid | Stepper | |
|---|---|---|
| Pen lift | Solenoid, driven up and down | Stepper motor |
| On power-up | The solenoid actuates and sits upright | No visible movement |
| Pen delays | Needed — see below | Ignored |
| terraForge pen type | Solenoid (Hardware) | Stepper |
Homing¶
No difference. Your machine has limit switches, so home it at the start of every session exactly as described in Your first plot.
Pen up and pen down¶
A solenoid has two positions, not a range:
| Z0 | Pen down, on the paper |
| Z1 | Pen up, clear of the paper |
There is roughly 14 mm of travel on the rail between them.
Different from the stepper
Do not use the stepper procedure of setting zero and jogging up by a set amount. Your pen has only two positions, and how far it lifts is decided by where you set the pen, not by a jog command.
Setting pen height¶
Set the pen so that when it lifts it clears the paper by between 5 mm and 14 mm.
Less than about 5 mm risks the nib catching as the paper warps during a long plot. Fourteen millimetres is the limit of the rail.
As with any pen plotter the down position takes practice — you want the nib firmly on the paper rather than just touching, so it keeps contact across any dips in the bed.
Gravity does the work
A solenoid machine has no spring pressing the pen down. When the solenoid releases, the pen drops onto the page under its own weight.
So set the pen slightly low rather than exactly level with the paper. Neither the bed nor the paper is perfectly flat, and gravity will keep the nib in contact across the dips — but only if there is somewhere for the pen to fall to.
Check the solenoid actuated
When the machine powers on, the solenoid should move to its upright position. If it does not, the pen will not lift during a plot.
terraForge settings¶
In your machine profile, set:
| Setting | Value |
|---|---|
| Pen type | Solenoid (Hardware) |
| Pen up command | M3S0 |
| Pen down command | M3S1 |
| Pen-down delay | 250 ms |
| Pen-up delay | 250 ms |
The delays give the solenoid time to physically move before the machine starts the next move — the pen-down delay runs before XY motion begins, and the pen-up delay before rapid travel. Without them the pen drags as it lifts, or starts drawing before it has landed.
Delays only matter for solenoids
terraForge ignores both delays on stepper profiles, which is why they are not mentioned in the main terraForge page.
Everything else in the machine profile is the same, including the bed size of 594 × 420 mm.
Lightburn¶
If you use Lightburn, the solenoid Z offsets are covered in Lightburn profiles and settings — a Z offset of 1 mm and −1 mm for Z step per pass, with profiles for machines with and without the pivot arm.
Configuration files¶
Your terraPen came with the correct YAML configuration already installed and set up for your toolhead, so there should be nothing to do.
If your machine needs its configuration reinstalling, get in touch on Discord rather than picking a file yourself — there are several solenoid variants and they are not interchangeable.